Annual Report 2003
RAP
Federal Research Station for Animal Production
Agroscope Liebefeld-Posieux (ALP) Tioleyre 4 CH-1725 Posieux Phone +41 (0)26 407 71 11 FAX +41 (0)26 407 30 00 info@alp.admin.ch www.alp.admin.ch
FAM
Federal Station for Dairy Research
Agroscope Liebefeld-Posieux (ALP) Schwarzenburgstrasse 161 CH-3003 Bern Phone +41 (0)31 323 84 18 FAX +41 (0)31 323 82 26 info@alp.admin.ch www.alp.admin.ch
FAT
Federal Research Station for Agricultural Economics and Engineering
Agroscope FAT Tänikon Tel. +41 (0)52 368 31 31 Fax +41 (0)52 365 11 90 info@fat.admin.ch
www.fat.ch
Foreword: The competence centre four years on ... 3
Retirement of FAM Director Christian Steffen ... 4
RAP... 5
Research into milk and meat production ... 5
Effects of grass and linseed with hay on the rumen fermentation and composition of milk in cows ... 5
Economic aspects of steer fattening with six different breeds ... 5
Effects of an outdoor pen on the health and performance of calves... 6
Production system with seasonal outdoor rearing of pigs... 7
Influence of apple pomace in piglet feed on the effects of the mycotoxin deoxynivalenol ... 8
The influence of conservation measures on the nutritional value of herbage... 9
Ensilability of different grass/clover mixtures ... 11
Official feed control... 11
The Federal BSE Unit ... 11
Survey on the dioxin content in feedstuffs... 12
Survey on contents of mycotoxin in cereals ... 12
Feedstuff analysis for third parties... 12
Analysis ... 12
FAM... 13
Milk, cheese... 13
Alternative procedure for drying cows' udders ... 14
Risk analysis implemented... 14
Development of resistance against macrolide antibiotics in enterococcus found in the faeces of calves fed on antibiotic milk... 15
Stronger proteolysis based on higher peptidase activity of Streptococcus thermophilus... 16
Transmission of Staphylococcus aureus between humans and cows... 17
Cheese and cheese forms meet marketing requirements ... 18
Dairy products (milk products and bee research) ... 19
The small hive beetle – a new threat for beekeepers? ... 19
Extent and cause of bee mortality in Winter 2002/03 ... 20
Meat processing – an expanding new research area ... 20
New findings on the fermentation behaviour of lactobacilli with nutritional value ... 21
Detection of whey cream in milk cream... 21
Services... 22
Evaluation of food safety in milk processing operations ... 22
All FAM lactic acid starter cultures are "bud"-label quality ... 23
Effects of geographical origins of samples on the measurement uncertainty of infrared milk analyses ... 24
Chemical-microbiological method for the quantitative determination of Clostridium tyrobutyricum spores in milk... 24
FAT... 25
Sustainable milk production... 25
Economic aspects... 25
Labour aspects ... 25
Evaluation with sustainability index ... 26
Model-based calculation of labour time requirements... 26
Sectoral effects of milk market reforms ... 27
Dust and ammonia emissions from housing systems in pig fattening ... 27
Emission reduction in slurry storage ... 28
Practical survey concerning total mixed rations in dairy farming ... 29
Minimal housing systems for dairy cattle... 29
Behaviour of unconfined sows in FAT 2 farrowing pens ... 30
How realistic is a robot for controlling dock?... 31
Spreading accuracy of trailing hose systems on slopes ... 31
Publications... 32
Foreword: The competence centre four years on
This report by the Competence Centre for Animal Production and Foods from Animal Origin provides key indicators of our activities in the 2003 reporting year and a review of the four-year service mandate period (FSMP). Supplementary to this report, we refer you to the report by the Agricultural Research Unit of the Federal Office for Agriculture and to our Internet sites, where you will find additional information and publications.
Animal production is still undergoing a process of sweeping change. Within the past four years, for example, the number of commercial milk producers dropped by 13.1 % to 34,600, while the number of commercial dairies producing Emmental cheese fell by more than half from 570 to 270. In many locations, long-established cooperative structures are gradually being disbanded. Milk prices are dropping around Europe as well as world-wide, posing problems for the export of Swiss speciality cheeses (Emmental in particular). Economic considerations are the current priority, and high product quality is a key criterion.
With the first four-year period of agricultural research stations with a service mandate drawing to a close at the end of 2003, it is now possible to draw up a review of the services provided and objectives achieved. Some 90% of the defined objectives under the mandate were achieved.
Applied research and the associated transfer of knowledge produced the following results Cost reduction through the development of alternative production and feeding systems for cattle and pig farming
Feed recommendations for ruminants and pigs, based on new findings on feed quality and conservation methods as well as their influence on milk and meat quality and on animal health.
A significant reduction in animal meal contamination in feed due to more frequent checks by the official feed control office, supported by the Swiss government's BSE unit
Targeted analysis of undesirable substances in feed and recommendations on corrective measures
High level of quality for milk and dairy produce
Assurance of the exportability of Swiss dairy products through, for example, the implementation of quality assurance and risk assessment systems.
Expansion of the ecological approach to alimentary production chains as a result of new advances and the implementation of minimal processing, e.g. through the development and use of FAM cultures with the "bud" label.
Innovations and new processes for the dairy industry
New findings on the economic importance of different production systems in fattened pigs and veal farming
Improvements in the animal-friendly breeding of domestic animals
Transparency in costs for working agricultural buildings in Switzerland and abroad.
Efficient problem-solving support for producers.
Over the past few years, FAM and RAP have built up process-based management systems. These systems received official approval in the year under review when the laboratories were reaccredited for ISO 17025 and both research stations received ISO 9001:2000 certification.
During the past 18 months, the service mandate and the associated product and project proposals for 2004 to 2007 were drawn up in conjunction with the management of Posieux and Liebefeld. Key strategic targets were also defined based on a foresight study and the research concept of the Federal Office for Agriculture. Customer requirements were largely addressed by members of the expert groups. For the first time, the research institutes are required to define their tasks in terms of the expected impact on customers, using an integrated performance/impact (IPI) model.
Work in the competence centre was based on close collaboration between the research institutes. As a logical consequence, it was decided to merge FAM and RAP into a single research unit under the management of Danielle Gagnaux. The Liebefeld and Posieux sites will continue in operation. This fusion allows the entire food chain for animal-origin products to
be covered and reduces overhead costs. On 1 January 2004, the federal research station for milk and meat production (ALP – Agroscope Liebefeld-Posieux) started operations and began working on its responsible and interesting tasks.
The Directors Danielle Gagnaux Christian Steffen Walter Meier
Retirement of FAM Director Christian Steffen
After 36 years in the service of FAM and 20 years as Director, Christian Steffen retired at the end of 2003. He began his professional career as an apprentice cheese maker and, following studies in agronomy (majoring in dairy technology) at the Swiss Federal Institute of Technology, became a research scientist, consultant and teacher specialising in cheese. In 1977, following several successful years in research and consulting, he took over the position of Vice Director of the Cheese Research Unit of FAM, where he was responsible for fundamental research into lactic fermentation and various aspects of cheese making technology. One of his main interests was the development of technical equipment for dairies and, in particular, for new cultures. Thanks to this scientific work, a number of deficiencies in cheese making were successfully corrected, leading to an impressive increase in the quality of Swiss cheese made from raw milk. His research findings were published in more than 130 publications. In 1989 he was awarded the Professor Hermann Weigmann Medal
"in recognition of his contributions to research in microbial processes in the manufacture of hard cheese and the introduction of controlled bacterial cultures in dairies producing Emmental cheese". In 2001, on behalf of FAM, Christian Steffen received the Swiss Cheese Award for the
"best research into Swiss cheese".
In his office as Director he began to review the management of FAM and reorganise it with a view to the future. Thanks to ongoing organisational refinement, rigid structures were dismantled to create a flexible enterprise. He emphasised the importance of involving all employees in a project as early as possible, so as to incorporate their ideas and recommendations from the outset.
In addition to managing the research station, he took over the presidency of the Swiss Dairy Industry Association in November 1987. During his ten-year term of office as President, the educational system for the Swiss dairy industry was substantially restructured. He was a sought- after expert in many other national and international committees.
Much more than a "fair-weather pilot", Christian Steffen also displayed outstanding management skills during times of crisis, addressing problems calmly and systematically. Examples include the various split defect problems in cheese, the listeria crisis in 1987 and, ten years later, the resistance of micro-organisms to antibiotics: thanks to his initiative, these problems were either solved or contained within controllable boundaries.
His expertise was also effectively applied to the process of merging the two research stations for animal production (RAP) and dairy production (FAM). At all times the change process was driven by a clear vision and well-defined objectives. The main aim of the new research unit was to expand research activities to cover entire production lines and to reduce overheads. Christian Steffen is convinced that the new Agroscope research unit for meat and dairy production (ALP) more comprehensively addresses the research and consultation needs of producers and, in so doing, will strengthen the impact of agricultural research.
On behalf of all members of staff I wish Christian Steffen a pleasant start to his new phase of life, and an enjoyable, happy and healthy retirement.
Max Rüegg, Vice Director
RAP
Research into milk and meat production
Walter Stoll
Walter.stoll@alp.admin.ch
Alongside ongoing research activities, one of the main tasks in 2003 was to prepare a new research program for 2004 - 07. A new integrated performance/impact (IPI) model was developed for products, to serve as a basis for new research projects. Using this model, five main areas in the field of integrated and biological agriculture were defined for the forthcoming research program. Three of these research areas focus on milk, meat and pork production systems. In addition, major importance will be accorded to dairy cow feedstuffs and the quality of cow, sheep and goat's milk.
In addition to the following research work, collaboration with the L’Abbaye de Sorens experimental farm was stepped up, paving the way for research into milk production systems, scheduled to start next year (2004). Work on the new “Yellow Book” (Swiss guidelines for swine nutrition) was also completed. and scheduled for publication in the course of next year. A sabbatical taken by one of our scientist at the lowa State University Meat Science Laboratory allowed to develop an international partnership.
Effects of grass and linseed with hay on the rumen fermentation and composition of milk in cows
Frigga Dohme
Frigga.dohme@alp.admin.ch
In terms of volume, linolenic acid is the most important fatty acid found in grass and linseeds.
In grass, it is found mainly in the form of glycolipids, while in linseeds it is found in the form of triglycerides. Although the majority of unsaturated fatty acids in the rumen stemming from feed are hydrogenated (saturated) by micro-organisms, it appears that the fatty acids in triglycerids are more sensitive to hydrogenation than those in glycolipids.
An experiment was conducted on six ruminally cannulated cows, to determine the extent to which the feeding of grass or linseeds affected rumen fermentation and the transfer of linolenic acid to milk.
While no difference was determined in the ingestion of dry matter, the intake of animals fed on linseeds showed significantly higher volumes of oleic acid, linoleic acid and linolenic acid. The average pH value in the rumen, the concentration of ammonia and number of bacteria were lower in the linseed variant than in the grass variant. The concentration of linolenic acid in milk fat was higher in cows fed on linseed than in those fed on grass, presumably due to the apparently more effective transfer from feed to milk. Compared with the linseed variant, significantly higher concentrations of conjugated linoleic acid and trans oleic acid were found in the milk fat of cows fed on grass.
Due to the varying intakes of linolenic acid, no clear conclusions can be drawn about the differences in rumen hydrogenation of these fatty acids. Nevertheless, the experiment demonstrated that more linolenic acid was transferred to milk from cows fed on linseeds than from those fed on grass.
Economic aspects of steer fattening with six different breeds
André Chassot, Pierre-Alain Dufey and Christophe Hermenjat (SRVA) Andre.chassot@alp.admin.ch
The results of a fattening trial with steers were used for an economic analysis comparing the breeds Angus (AN), Simmental (SI), Charolais (CH), Limousin (LI), Blonde d'Aquitaine (BL) and Piemontese (PI). The fattening period ranged from 300 kg live weight to the optimum fattening score for slaughter (CHTAX: Note 3 for the fat tissue). More than 95% of margin variations are attributed to differences between purchasing costs and produce of sales. Factors
of success are: dressing percentage, carcass conformation, and matching the degree of precocity with the feeding intensity such that growth is optimised within the limits set by the market. The highest comparable margins per large animal pen were scored by the Ll and CH breeds (Fig.1). Better returns can be achieved for late-maturing breeds BL and Pl by increasing the intensity of feeding and/or opting for an insufficient fatness score. Better returns can be achieved for early-maturing breeds AN and Sl by increasing the slaughter weight as shown in figure 1. In the case of AN, the feed intensity must be reduced. In the case of Sl this is not necessary since the fatness score remains unchanged for a larger weight range.
Figure 1: Comparison of margins per large animal pen (LAP) and breed.
Dotted areas: results of AN and SI breeds following simulation
Effects of an outdoor pen on the health and performance of calves
Isabelle Morel, Gilles Aeschlimann, Anita Philipp and Marc Boessinger (LBL) Isabelle.morel@alp.admin.ch
An experiment using 195 calves – conducted in three series each based on three treatments – studied the effects of outdoor access on the health and performance of calves during the weaning stage. The control group was reared exclusively in an unpenned shed, while animals in the two specimen groups were given outdoor access. One specimen group was fed hay indoors, the other was fed hay outdoors.
Hay feeding in an outdoor pen encourages
The rations were the same for all three variants and consisted of milk, concentrate feed and hay. The results over all three series showed no significant differences between the three variants. However, evaluation of the individual series revealed significant differences for specific parameters.
The conclusion is that the influence of outdoor access on health and performance can vary depending on farm conditions. The positive effects of outdoor access may prove useful, particularly in cases of higher susceptibility to infection and in farms with regular outbreaks of respiratory disease.
In such cases it is recommended that animals be fed hay outdoors, assuming a sufficiently good quality of hay and good weather conditions.
Production system with seasonal outdoor rearing of pigs
Peter Stoll and Giuseppe Bee Peter.stoll@alp.admin.ch
Low-cost production systems for pig rearing are of interest to Swiss farms, particularly those with free arable land. Increased flexibility is achieved through a reduction in production costs or a change to this type of activity without excessively high levels of investment. In conjunction with the Schüpfheim Agricultural Training and Consulting Centre, part of such a production system was developed at Burgrain and optimised for Swiss conditions.
The factors to be examined were: crop rotation, impact of production system on fattening performance, meat and fat quality and on the soil structure and profitability.
The pigs were provided with four different grazing cultures: a natural meadow, a wheat-rye mixture, a grass-clover mixture, and turnips. These cultures varied in suitability. In contrast to the other cultures, the rye proved unpopular. The grass-clover mixture was eaten well, although suppressed growth was observed each time this plot was grazed. The intake of concentrated feed rose to 2.15.kg per kilogram of growth (weight range 18 to 115 kg live weight).
This supports the conclusion that a substantial portion of the required energy came from the pastureland during the fattening period.
In our experience, the activity portion in outdoor rearing accounts for 10 to 15% of total energy requirements. The estimated energy intake on the pastureland is therefore 27 to 30%.
The fattening animals were slaughtered at 106.4 kg live weight. The fattening performance and slaughter yield of the animals were good (732 g daily growth and 56 % of valuable cuts). The fat quality was very good: the average fat score was 57.6, and the maximum was 61.5.
In other words, none of the animals exhibited a fat score above 62 (deduction threshold).
During wet weather, the soil of grazing plots – and particularly frequently used areas such as the eating area and wallowing areas – is trampled and compacted.
For the purpose of assessing the economic aspects of the production system, the study covered free-range sows, free-range fattening pigs and free-range sows selected for further breeding. The associated margins (incl. RAUS and BIS margins) per hourly unit of labour (HLU) were CHF 40.30, CHF 36.30 or minus CHF 86.80. Due to the relatively low number of suckling pigs (37) the mean margin per hourly labour unit (HLU) was modest at CHF 9.96 CHF/HLU. Since the labour expended on rearing fattening pigs with a higher number of piglets is only marginally higher, a margin of CHF 20 to CHF 24/HLU would be realised for the standard birth rate of 10 piglets per litter.
Grazing on rye-wheat culture
Project findings to date can be summarised as follows:
• During wet weather, the soil rapidly turns into a mudbath. However, this is harder on the human eye than it is problematic for pigs. Nevertheless, the animals must be provided with a dry resting area strewn according to the ambient temperature. Grazing by pigs does not affect soil structure to an excessive degree, since no visible traces can be found in subsequent cultures.
• Rye is not a suitable grazing crop
• If turnips are used, they must be sowed at the end of April at staggered intervals wherever possible.
• Good fattening performances can be achieved when fattening pigs are reared outdoors. The energy intake on the pasture amounts to between 25 and 30 % for the cultures used.
• Consistent observation of PUFA-MUFA recommendations results in good fat tissue quality.
Shade and a wallowing area have proved beneficial.
• It pays to devote more time to the animals during the farrowing phase and the subsequent suckling period.
Grass-clover grazing
Influence of apple pomace in piglet feed on the effects of the mycotoxin deoxynivalenol
Andreas Gutzwiller, Levente Czeglédi, Peter Stoll and Lukas Bruckner (IVI) Andreas.gutzwiller@alp.admin.ch
The mycotoxin deoxynivalenol (DON) produced by fungi of the genus Fusarium depresses feed intake in pigs and is thought to weaken their immune system. The aim of this experiment was to determine whether the addition of apple pomace in piglet feed reduces the suppressive effect of DON on feed intake.
116 piglets were fed the following diets for a period of five weeks: 1. no DON and no pomace (D-P-); 2. no DON and 8 % pomace (D-P+); 3. 3
mg/kg DON, no pomace (D+P-); 4. 3 mg/kg DON and 8 % pomace (D+P+). Animals fed on D-P-, D-P+, D+P- and D+P+ grew 376, 369, 334 and 369 g per day.
Injection of the plant extract phytohaemagglutinin in the skin produces localised swelling, comparable with skin reaction to a tuberculin sample
The tendential interaction between DON and pomace (P= 0.12) indicates that pomace could modify the growth-depressing effect of DON. Animals receiving the dietwithout pomace which was contaminated with DON gained significantly less weight (P = 0,03) than those fed the diet D-P-. Animals fed on feed contaminated with DON with added pomace tended to grow faster (P = 0,07) than those fed on diet D+P-. Feed conversion, antibody formation following vaccination against porcine parvovirus, the albumin content in blood plasma, and the number of red and white blood cells were not affected by DON. The intake of DON stimulated the cell mediated response to the intradermal injection of
phytohaemagglutinin.
The experiment shows that apple pomace may alleviate the growth depression caused by DON. The possible positive effect of apple pomace in the presence of DON will be further examined in a future trial.
To determine the possible effects of DON on internal organs, some piglets were slaughtered on completion of the trial. The local skin reaction in the knee area following the injection of phytohaemaglutinin is clearly visible.
The influence of conservation measures on the nutritional value of herbage
Yves Arrigo
Yves.arrigo@alp.admin.ch
The digestibility of fodder – the main parameter for evaluating the nutritional value of a feedstuff – is determined from experiments conducted on animals. An in vivo analysis using sheep lasts 30 days. This means that the green fodder must be conserved since its chemical composition changes rapidly over time. However, in order to ensure representative results for the initial fodder, the applicable conservation method must guarantee minimal change in the content.
The point of departure for this project was the introduction of a test drying installation at the Posieux research station, which enables the controlled conservation of herbage as a replacement method for labour- and energy-intensive conservation by freezing. The two conservation methods designed for experimental use were compared with other commonly practised conservation methods with a view to supplementing our data and verifying our predictions on nutritional value.
For three consecutive years, an early and late vegetation stage was harvested from the same plot. The fodder was conserved by means of six different methods:
Freezing at -20 °C; portions of 5 kg each in a plastic sack
Drying in the experimental installation (drying temperature 30 °C, humidity < 50 %)
•
Drying in the field followed by barn-drying
•
•
•
•
Field drying
Silage with 30 % of dry substance after light wilting on the field Silage with 50 % of dry substance after wilting on the field
The 36 samples were analysed for their botanical composition and more than 60 parameters such as amino and fatty acids. For each conservation method, the digestibility of the fodder was obtained by means of in vivo tests.
Freezing – this method is highly labour- and energy-intensive
The results of the digestibility tests show no significant differences between the various methods (Fig.
2). As with previous tests, the stage of development as well as the botanical composition significantly affect digestibility. However, no significant difference was observed in organic matter or raw protein. This means that the conserved fodder obtained from the test drying installation is ideal for in vivo tests. In addition, the many analytical findings obtained in the course of the project have allowed us to add to our herbage database and update the nutritional table in Fodder recommendations and nutritional value tables for ruminants ("Green Book").
Figure 2: Digestiblity of organic matter (dOM) as %
60 65 70 75 80 85 90
1st cut early 2000
1st cut late 2000
3rd cut early 2001
3rd cut late 2001
1st cut early 2002
1st cut late 2002
dOM, %
freezing experim. inst.
barn drying field drying silage 30% DM silage 50% DM
Ensilability of different grass/clover mixtures
Ueli Wyss
Ueli.wyss@alp.admin.ch
In Switzerland, grass/clover mixtures are sown for leys, whereby the clover plays a key role. The mixtures are regularly revised for quality, yield and durability as part of variety testing programmes.
No systematic tests are carried out to determine the ensiability of the various mixtures. Due to their high protein content and low dry matter content (DM), however, the different types of clover are regarded as being unsuitable for ensiling.
Between 2000 and 2002 various tests were conducted on grass/clover mixtures and pure stands (species of grasses and clover). For the experiment, we used the first and third cut. The fodder was pre-wilted (25 to 30 % DM), short chopped and ensiled in laboratory silos.
In the various mixtures, the proportion of clover was always higher in the third cut than the first. The sugar content in the green fodder differed, being higher in the first than the third cut and hence affecting fermentation. Lactic fermentation was more intensive and first-cut silage exhibited better fermentation quality and higher DLG scores, respectively. But the botanical composition of the mixtures also influenced the fermentation quality. For instance, raygrass had a positive effect on fermentation quality (correlation 0.47) and cocksfoot had a negative effect (-0.35). Cocksfoot exhibited a much lower sugar content and higher crude fibre content than raygrass harvested at the same date. The proportion of white and red clover in the mixtures had a slightly negative effect on fermentation quality. The fermentation quality in the mixtures was primarily determined by means of nutrient contents rather than botanical composition. The correlation between fermentation quality and sugar content in green fodder was 0.66 and between fermentation quality and crude fibre content -0.61.
Official feed control
Daniel Guidon
Daniel.guidon@alp.admin.ch
34% of the samples were subject to minor complaints, while the number of complaints liable for costs was 8.5 %. This corresponds to a drop of 18 % and 32 % respectively. In two cases (2002: 9) charges had to be brought due to the anticipated negative effect on the quality of food produced (milk, meat, eggs). In both cases the fodder was contaminated with pharmaceuticals from the manufacture of fodder pharmaceuticals. Too little care had been taken in the cleaning of production installations.
In 134 samples of end products or individual feedstuffs, the presence of GM products was detected.
The samples were either tested by RAP inspectors (53) as part of the official fodder control procedure or by customs authorities (81) on import into Switzerland. None of the samples exceeded the declaration limit of 3% defined in the food ordinance.
In 2003, 853 inspections were conducted on the premises of 480 producers of additives, premixes and mixed fodder. Each producer was inspected at least once, and larger-scale operations several times.
The most common reason for non-compliance with requirements was hygiene (75 complaints).
Other reasons for complaints were incomplete declarations, non-compliant storage of additives and incomplete documentation on the manufacturing process.
The Federal BSE Unit
Various tasks were performed as part of the Federal BSE Unit's performance contract. The number of microscopically inspected feedstuff samples increased by 20 % to 1502. In four cases, traces of contamination by animal material (which has been banned in all feedstuffs since 1 January 2001) were found. The affected products had to be recalled and destroyed by the manufacturer. The percentage of positive samples was 0.3%, compared to 1.5%, 2.9% and 14% for 2002, 2001 and 2000 respectively.
Between 1991 and 1999 animal material was detected in 38% of the samples inspected during official feedstuff controls. At that time, meat meal and similar products were still commonly used in the production of fodder for pigs and poultry.
The main reason for the above-mentioned complaints was inadequately cleaned equipment in which animal material had been stored or processed in previous years. Due to their low incidence, the importance of such findings has declined sharply. However, the feedstuff sector is making every effort to eliminate all final traces of animal meal from the food chain.
The feedstuff control unit collaborated with the BSE Unit to draw up certification documentation. The ISO 9001:2000 certification audit conducted in December 2003 was successful, resulting in certification not only of the entire Posieux research station but also the BSE Unit and, by extension, the RAP feedstuff team.
Survey on the dioxin content in feedstuffs
A survey was conducted on the drying method and applicable fuel material in 70 grass-drying installations throughout Switzerland. 21 feedstuff samples were taken and examined for dioxin content. The results were reassuring: none of the samples exceeded the maximum content of 0.75 ng WHO-PCDD/F-TEQ per kilogram defined in Annex 10 of the Feedstuff Ordinance. This is attributable to the fact that all operators use extra-light heating oil. Direct dehydration using heavy oil or charcoal generally results in a higher dioxin content in dried fodder.
Survey on contents of mycotoxin in cereals
In contrast to 2002, virtually no increases in mycotoxin content were detected in 117 analysed cereal samples. The dry summer of 2003 inhibited the growth of mould (fusaria) and hence also the production of mycotoxins in fodder cereals. The quality of Swiss cereals harvested in 2003 can therefore be considered flawless.
Feedstuff analysis for third parties
The number of samples examined on behalf of third parties increased in 2003 by 20% to 5909, primarily due to the larger number of raw fodder analyses (+565 samples) and the large number of fat and fatty acid analyses (+789 samples). The number of samples for GMO detection rose by 83 to 1612. Demand for this type of analysis remained high. The number of mycotoxin analyses performed for third parties declined slightly, although mycotoxin reportedly remains a major problem, particularly in pig farms.
Analysis
Jean-Yves DeruJean-yves.deru@alp.admin.ch
Despite the downward trend in the number of incoming samples (- 9 %) compared to 2002, the general scope of work has increased. The average number of parameters requested per sample rose from 9 to 12, leading to a 12% increase in analyses to 164,000. 43.5% of the samples were from research activities, and the remaining 13% from official feedstuff controls.
2003 also saw the introduction of measurement uncertainty in accordance with the requirements of the ISO 17025 accreditation norm. This costly and complex process of determining measurement uncertainty will enable better interpretation of results for our internal and external customers.
During the course of this year, apprentice and laboratory assistant training will be adapted in line with the new procedure. The entire training concept has been completely revised in order to
guarantee better practical training, improved deployment of staff, and to adapt courses to more accurately meet the needs of our employees.
In the field of analytical work, antibiotic screening remains much in demand for customers in Switzerland and abroad despite the fact that detection of positive samples has become rarer.
A more sensitive method for detecting the concentration of probiotic yeasts was introduced following collaborative testing (chain analysis). An improved method for detecting the concentration of Enterococcus faecium was also applied. While these new methods, which take better account of interference (for example by copper or due to the composition type), have proved more effective than previous methods, the differences are not exhibited systematically. For this reason, the old method is used alongside the new one for detecting germ concentrations.
As a result of active collaboration between the Posieux research station and various international organisations in the field of GM organisms, the associated knowledge was transferred to Mexico and South Africa during two workshops on the topic.
A system for optical emission spectrometry (ICP-OES) was installed and put into operation for our chemical unit. The system allows the following macroelements to be simultaneously detected: Na, K, Ca, Mg, Fe, Cu, Zn and R. The new system has replaced the older photometric method for detecting calcium and phosphorus. The older absorption spectrometer with graphite oven, no longer in use, has also been replaced by a new system for the detection of trace mineral elements. The occasion was used to achieve a rarely-seen combination of the three FIAS-GF-AAS methods for analysis of selenium traces. Moreover, the Posieux research station also sponsored a University of Fribourg dissertation on minerals, which resulted in an analytical method for selenium macroelements using ICP-OES.
Since June 2003, amino acids have been analysed using the HPLC method with AccQ Tag precolumn derivatisation and fluorometric detection in a water alliance system. Other new methods include the analysis of alcohols in silage samples as well as the examination of condensed tannins and a method for estimating the degradability of nitrogenous agents by means of NIR spectrum analysis of feedstuffs.
FAM
Milk, cheese
Hans-Peter Bachmann
Hans-peter.bachmann@alp.admin.ch
The quality of Swiss commercial milk and cheese is high. Research and consulting services provided by the FAM help to retain this high quality. Given the difficult situation in which the Swiss dairy industry finds itself, quality problems would have dramatic consequences. Collaboration on the
"Profi-Lait" project is being further stepped up at ALP. Detailed results have been made available on the composition and attributes of goat milk. A risk analysis system has been developed to provide an important basis for determining the exportability of Swiss cheese made from raw milk. The aim now is to familiarise dairy operators with the new system.
Capillary electrophoresis is used to determine the percentage of whey protein in cheese.
FAM has become a recognised partner for innovation within the Swiss cheese sector. New cheese manufacturing processes have been developed and are already being implemented or are scheduled for implementation in the near future. he conference held at the Posieux research station on 27 August 2003 by the Swiss Association of Agricultural Engineers and Food Technology Engineers on "The future outlook for Swiss cheese" demonstrated that cheese research is well positioned to address current issues and
achieve marketable results. Important progress has been made in the field of authenticity and aroma creation, with the potential to reinforce the status of Swiss cheese as a premium product. More and more practical trials are being conducted in dairies with the aim of acquiring new knowledge for discussion groups, with the main focus on economically relevant topics.
In the year under review Bio-Suisse authorised an anti-foam agent which will allow our entire range of lactic acid bacteria cultures to be marketed under the "bud" seal of quality, thereby differentiating Swiss cheese from foreign competitors.
Alternative procedure for drying cows' udders
Jürg Maurer and Walter Schaeren Juerg.maurer@alp.admin.ch
Since January 2003, FAM has been collaborating with the Dairy Inspection and Consulting Service as well as interested milk producers to conduct practical trials on the use of Orbeseal® for drying cows' udders. This antibiotic-free udder protection agent is injected into each quarter using a syringe, to mechanically seal the teat and protect the udder from infection during the dry period.
More than 30 farms participated in trials to determine the advantages and disadvantages of Orbeseal® compared with other drying processes (using antibiotics, no udder protection).
According to initial findings, the use of Orbeseal® is comparable with treatments based on antibiotic drying agents. According to statements by milk producers, application of Orbeseal® results in immediate, tight sealing of the teats. Even cows with a high milk yield and hence high udder pressure generally express no more milk following this dry cow therapy. Most of the Orbeseal® is expelled in the form of a viscous mass during the first post-calving milking.
X-ray of teats shortly after applying Orbeseal® (Photo:Pfizer AG)
However, in individual cases, some remnants of the Orbeseal® were found in milking utensils several days after calving. Since this udder protection agent adheres strongly to surfaces, milk producers are advised to use a bucket to milk cows for the first few days after calving, in order to prevent contamination of the milking system. To date, 274 of the cows participating in the trial have calved. In general, Orbeseal® offers a good preventive alternative to antibiotic dry cow therapy.
Risk analysis implemented
Marc Mühlemann, Georges Bühlmann and Melchior Schällibaum Marc.muehlemann@alp.admin.ch
Protecting consumers against health risks is becoming increasingly important as the food industry becomes globalised. Risk assessment is used to determine food-related health risks and to identify ways of preventing or reducing such risks. Since a number of countries classify raw milk products are risk products from a microbiological standpoint, FAM has designed a system to assess the development and propagation of risks along the food chain (Fig. 3). This interdisciplinary method of risk assessment provides operators, institutions and authorities with an informative overview that throws light on cause and effect and allows them to evaluate risk-minimising measures. The concrete task of reducing risks along the food chain is performed by food producers and food processing companies within the context of their HACCP (Hazard Analysis and Critical Control Point) programmes. In the case of listeria contamination of Swiss hard cheeses, the link with listeriosis was dismissed. The contribution to listeriosis was confirmed to be at most minimal, and it was possible to evaluate the minor cost implications and design a model for predicting cases of listeriosis caused by different food groups. On the operational side, models were designed to demonstrate the importance of the heating temperature, existing hygiene measures and quality standards pursued, and efforts stepped up to localise and quantify risks.
Figure 3: Risk diagram for the production of Emmental cheese
Communication, the link between research and practice, is gaining importance in our internal and external collaborative ventures, and will help to ensure the efficient application of risk assessment in the interests of consumer safety.
Development of resistance against macrolide antibiotics in enterococcus found in the
faeces of calves fed on antibiotic milkIsabelle Würgler-Aebi, Melchio Schällibaum, Michael Casey and Walter Schaeren Melchior.schaellibaum@alp.admin.ch
A large number of antibiotics are used in animal production for therapeutic purposes. Milk containing antibiotics, produced during the cow's treatment and the following quarantine period, is normally fed to calves and pigs. Calves are usually kept with cows in the same stall. No information is available on the effects of milk containing antibiotics on the selection and spread of resistant bacteria. In such a scenario, the entry of resistant enterococci into the food chain due to contamination of raw milk during milking cannot be excluded. As a component of natural microflora in milk, enterococci as also known for their multiple resistance to antibiotics and their ability to pass on resistance to other bacteria.
Figure 4: Relative numbers of resistant enterococci in Group B calves' faeces duringthe trial from Day 7 to Day 28. The lines above the bars show the standard deviation in each case.
15 160
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Five cows were administered two intramammary injections of the macrolide antibiotic Spiramycin at an interval of 24 hours. The milk was collected in a separate pool over a 14-day period. 30 calves were divided into three groups: Group B (fed from Day 0 on milk containing Spiramycin) and Group K+ (fed on normal milk) were kept in the same stall and had direct contact with each other. Control group K- (fed on normal milk) was housed in a separate stall without any contact with the other calves. During the trial, faeces samples were taken every three days and milk samples were taken twice a day, stored at -20° C and analysed to determine the number of macrolid-resistant and macrolid-sensitive enterococci. The relative number of Spiramycin-resistant enterococci in the faeces of Group B rose from just on 18 % at the start of the trial to almost 100 % on Day 3, dropping on Day 28 to 72% (Fig. 4).
No important quantitative transmission of Spiramycin-resistant enterococci was observed from Group B to Group K+ .
Stronger proteolysis based on higher peptidase activity of Streptococcus
thermophilusMarie-Therese Fröhlich-Wyder, Dino Isolini and Michael Casey Marie-therese.froehlich@alp.admin.ch
The aminopeptidase PepN, which is widespread among lactic acid bacteria, plays an important role in proteolysis since it releases various amino acids when degrading different peptides, thus playing a role in peptidolysis. The 235 Streptococcus thermophilus strains in the FAM collection can be divided into two groups. One group consists of strains with one to ten times stronger PepN activity (up to 65 nM/min/OD) than the other group (from 6 nM/ min/OD). On the assumption that this phenomenon is not coincidental, dairy trials were conducted on pasteurised model hard cheeses to observe whether this different peptidase activity affects the cheese and releases more, smaller peptides or amino acids. In all, four strains – two with stronger and two with weaker PepN activity – were used in combination with the CM 170 lactobacilli.
Figure 5: Free amino acids in six-month-old pasteurised model hard cheeses (n=6). The lines above the bars show the standard deviation in each case.
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he strains with a stronger PepN activity produced a significantly higher content of free amino acids in the six-month-old hard cheese (Fig. 5) and exhibited weaker dispersion. Since acidification was slightly slower in cheese with "strong" PepN activity, the water content in this group was also higher. This had a positive effect on proteolytic and peptidolytic enzyme activity. However, the ratio of smaller (NPN) peptides to larger (WLN) showed that peptidolytic activity in the
"strong" PepN activity group was actually stronger. Since the proportion of WLN content accounted for by NPN was, on average, some 4.5% higher for this group, peptidolysis was in fact stronger due to a higher level of PepN activity. Sensory assessment was unable to identify any significant influences, but the "strong" PepN activity group was slightly more popular and had a more intensive aroma as wel as scoring slightly higher on quality. No. 127 produced particularly interesting results and achieved the highest overall quality rating.
Transmission of Staphylococcus aureus between humans and cows
Michael Casey, Walter Schaeren, Richard Eigner (Univ. Bern) and Ivo Heinzer (Kantonsspital Aarau)
Walter.schaeren@alp.admin.ch
Staphylococci, and Staphylococcus aureus in particular, is an important infectious agent in humans (e.g. purulent abscesses, inflammation of the lung and heart muscles) and animals (mastitis in particular). S. aureus is also a cause of food poisoning. Frequently, humans and animals are also symptom-free carriers of S. aureus (among other things in the pharynx area). As part of a dissertation for the Faculty of Veterinary Medicine at the University of Berne, and in conjunction with the Cantonal Hospital of Aarau, a study was conducted into the possibility and frequency of transmission of S.
aureus between farmers and their livestock. 116 isolates of S. aureus were analysed at FAM from nose swabs taken from farmers (21) from two geographical regions of Switzerland and from milk samples of infected udder quarters (95) of their animals. A method for amplifying the spacer regions between the 16S and 23S rRNA genes described by Jensen et al. (Applied and Environmental Microbiology, 1993) was used to characterise the different variants. Sixteen different variants were found in the 95 isolates taken from cows and 16 variants in the isolates taken from nose swabs.
R H C C H C C H C C H C C
1 2 3 4 5 6 7 8 9 10 11 12 13
R = Reference, H = Human, C = Cow
Fig. 6.: Analysis of ribosomal RNA in S. aureus isolates of different origins. R = Reference, H = Human, C = Cow
However, the same variants in isolates from a human and a cow belonging to the same farm were found in only three cases. In other words, in the majority of the S. aureus isolates from cows and from farmers, the variants differed. Consequently, transmission between humans and cows appears to be the exception. Figure 6 shows an example of results from the PCR analysis of 12 isolates. Variant 5 (farmer) and Variant 7 (cow) exhibit the same gene.
Cheese and cheese forms meet marketing requirements
Cédric Frangnière, Andreas Thomet and Karl Schafroth Cedric.fragniere@alp.admin.ch
A milk concentrate produced by micro-filtration offers a simple method of manufacturing soft, fresh or semi-hard cheeses. The process is also highly interesting from an economic standpoint, since lower investments in equipment and infrastructure are required, the process is less labour-intensive and can be performed continually, and it produces a by-product in the form of low-germ milk serum (permeate) with valuable whey protein.
This new process is simple and offers a number of possibilities. The milk is first concentrated using a 0.1 µm pore size filter. Only the fat and casein components of the milk are concentrated. The process
reduces the energy costs involved in concentration, and produces a concentrate whose chemical composition is comparable to that of soft cheeses.
Examples of forms produced by this process
The MF concentrate is then coagulated and acidified in the same way as in traditional cheese making processes. The major advantage of this process is that it permits the addition of other ingredients such as salt, herbs, rennet and ripening cultures or fruit during this production phase. The mass is then poured in liquid form with no whey runoff, allowing manufacturers to produce a wide range of forms, from simple to intricate . More money is invested nowadays in packaging. A product of this type requires no expensive packaging since it is differentiated through its form alone. Experts attending various practical demonstrations were impressed by the creative forms and high quality of the different cheeses.
Dairy products
(milk products and bee research)
Peter Gallmann
Peter.gallmann@alp.admin.ch
We expanded our research field to include other food of animal origin beyond milk products and honey bees. The preliminary project on meat processing provided the basis for a new area of research. Thus we can complete the whole food chain covering research from feedstuff to the end product or from the stable to the table for all animal products.. Additionally, by setting up our own food research unit, the last link in this chain, the effects of such food on human health was incorporated. These concepts were very well appreciated by food and nutrition related sectors and food industries. The meat producing sector also responded positively due to the fact that its interests will now be supported by state-funded applied research.
Last spring 2003, the apiary sector suffered extraordinarily high colony losses following over- wintering. According to our data and findings, there was no cause for panic if only our recommendations were consistently followed, the chances of damage limitation were good.
Nevertheless, the small hive beetle poses a new and very serious threat to bee-keeping.
The Swiss dairy sector has been restructured following last year's turbulent economical developments. Our partnerships were adapted to the new conditions. As in previous years, we succeeded in offering to the sector key assistance such as statements, advice, expert findings and recommendations. Additionally, specific project work was set up with external partners, and members of staff were sent on short-term assignments to provide on-site assistance with problems.
The small hive beetle – a new threat for beekeepers?
Anton Imdorf
Anton.imdorf@alp.admin.ch
The small hive beetle, Aethina tumida, native of sub-Saharan Africa, is threatening to become a new global bee parasite (photo). Since its discovery in South Carolina (USA) in 1996, it has spread out to 29 US states and neighbouring regions of Canada. In 2000 it was also found in the Nile valley in northern Egypt, and in 2002 in Australia. Last spring 2003, 1500 artificial swarms were imported into Germany from the USA; as a result, the possibility of the hive beetle's propagation in Europe can no longer be excluded. The Federal Office for Veterinary Medicine has therefore conducted a situation analysis and banned bee imports from affected countries. The same measures have also been taken within the EU.
The small hive beetle and its larvae on a honeycomb (Photo USDA).
This new bee parasite has caused major colony losses in the south of the USA. The beetle primarily seeks bee colonies for propagation purposes and has a flight range of up to 16 kilometres. In the USA, adults and larvae are chemically treated, therefore the parasites became resistant to such agents soon. There is an urgent need to develop alternative ways of pest control, similar to the measures taken against Varroa destructor. A number of biological options must be tested such as pheromone traps, sterilisation of males and disorientation, as well as strategies that use substances such as organic acids and volatile oils which do not affect the quality of bee products.
At the same time there are major knowledge gaps in the field of biology, behaviour and epidemiology. Following discussions with the Federal Veterinary Office and apiary associations, the Centre for Bee Research provided bee-keeping consultants with the requisite information on these new parasites so that they can advise bee-keeping groups accordingly.
Extent and cause of bee mortality in Winter 2002/03
Jean-Daniel Charrière, Anton Imdorf and Franz-Xaver Dillier Jean-daniel.charriere@alp.admin.ch
Between fall 2002 and spring 2003, bee-keepers suffered unusually high colony losses (photo).
Among the possible causes put forward were insufficient varroa control, late honeydew flow, certain cultivated crops (sunflowers, canola seed, maize) or bee viruses. To obtain a more detailed picture of the losses in Switzerland and identify possible causes, we conducted a survey by publishing a questionnaire in various Swiss apiculture publications. 612 completed questionnaires were returned to us. At 18%, the average percentage of over wintering losses in Switzerland was significantly higher than the standard 10% but clearly below the 30%
reported in the press in the spring of 2003. The survey was unable to provide evidence of any specific cause for the higher losses suffered last winter. Either there are multiple factors at work, or there are other causes which have not been taken into account (e.g. bee viruses). A diagnosis is not possible at this point in time.
The cause of bee colony mortality must be sought in multiple interacting factors.
Canola, maize or sunflower crops in the vicinity of beehives do not appear to play a role, since losses in such areas were only slightly above average. Major losses were suffered by some beehives with late honeydew flow. Slightly lower losses were recorded by beehives where varroa control was correctly performed. Generally speaking, varroa does not appear to be the main cause of bee colony losses. Similar losses were recorded on several occasions in the 20th century, at a time when neither varroa nor sunflower crops existed in Switzerland.
Meat processing – an expanding new research area
Ruedi Hadorn
Ruedi.hadorn@alp.admin.ch
About one sixth of added value in the Swiss agricultural sector is generated from the sale of meat products (sausage, cold cuts, meat for cooking and cooked meat). To date, no state-funded research has been conducted in this area. As part of the new strategic direction in agricultural research, the Federal Office for Agriculture commissioned the two research stations for animal and dairy products to formulate a concept for research into meat processing. The initial phase involved contacting meat processors and industry organisations as well as meat producers, authorities, research and educational institutions, and presenting the project to them in order to identify current problems in
the meat sector. More than forty research requirements were identified and summarised. Based on the aim of establishing an applied research programme to support the industry, the following priorities were defined for the 2004 – 2007 research period: Examination of the importance of the fat score in pigs based on selected meat products; formation of new competences in the field of microbial meat fermentation; development of methods and procedures for regional, natural meat products;
formulation of solutions for technological problems experienced in practice; formulation and dissemination of new data on nutrition and physiology, with a view to verifying the importance of meat in human nutrition; geographical origin of poultry and dried meat in order to ensure authenticity. The aim is to concentrate on meat processing and meat technology, since other institutions are responsible for research into food safety.
New findings on the fermentation behaviour of lactobacilli with nutritional value
Ulrich Zehntner and Philipp Ritter Philipp.ritter@alp.admin.ch
From a chemical point of view, calculating bacterial lactic acid fermentation is a simple procedure: A defined quantity of lactose produces four times the quantity of lactate and sufficient energy for bacterial cell sustenance and growth. This formula is too simplistic, however, since lactose is also the main source of the organically important element, carbon. Somewhere in the fermentation process, metabolites are diverted for cell formation and, as a consequence, are no longer available for the production of lactate. The biologically correct benchmark is the carbon or C balance: an essential factor in the technical and economical usability of fermented substrates.
A C-balance of this type was applied to two lactic bacteria, Lactobacillus acidophilus and gasseri. The following results were obtained:
• Lactose or glucose are the principal sources of carbon for both varieties, but the proportion is heavily dependent on strain and media and varies between 75 to 95%.
• Up to 25% of the carbon is provided by sources other than lactose.
• Up to 50% of the available lactose or glucose remains unfermented.
• Only 1 to 5% of the substrate carbon is used for biomass. Hence the diversion of carbon for internal cell processes does not affect commercial value.
• The quantity of CO2 produced is negligible.
• Curiously, fermentation behaviour is strongly influenced by the composition of the surrounding air and the gas released in the medium. The total displacement of oxygen by nitrogen acts as an inhibitor. Small quantities of oxygen in a gas milieu dominated by CO2
can have a positive effect, depending on the strain.
The results provide an indication of technical ways of influencing the complex fermentation behaviour of new strains in rich media which are difficult to define chemically.
Detection of whey cream in milk cream
Daniel Wechsler and Ueli Bütikofer Daniel.wechsler@alp.admin.ch
The quality and shelf life of butter and dehydrated butter – both important ingredients in the food industry – largely depends on the selection of raw ingredients (milk cream, whey cream). When cheese is manufactured in a copper kettle, whey cream is produced with a copper content roughly thirty times higher than in milk cream. The copper content can therefore be used as a meaningful criterion in detecting whey cream. The oxidising effect of copper limits the shelf life of whey cream butter. It is therefore important for the milk fat used in the manufacture of biscuits, chocolate and ice cream to be stable, since fat defects such as oxidation or rancidity should not occur before the expiry date. This requires the separate collection and processing of milk cream and whey cream.
In cooperation with the butter industry and the Swiss College of Agriculture in Zollikofen, copper balances were defined for the processing method practised by an industrial buttery. Based on production samples, the influence of whey cream and milk cream processing on the copper
content of end products was studied in detail. The copper balances obtained show that copper is present only during the watery product phase and, by separating water through centrifugation, is virtually completely eliminated in the industrial manufacture of dehydrated butter. New analytical methods for milk cream controls were developed in parallel with this study.
In future, glycomacropeptide (GMP) can be used to ensure and reliably verify minimal mixing of milk cream with whey cream (Fig. 7). The GMP method has already been successfully applied in practice.
100 c
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Figure 7: GMP detection in cream samples using an HPLC. Chromatographs of whey cream (a) and milk cream (b) and of a milk cream sample containing 5% whey cream.
Services
Peter Thürlemann
Daniel.gerber@alp.admin.ch
Milk and milk products must be faultless in terms of quality and safety. To meet this criteria, high standards must be satisfied at every stage of the entire milk production and milk processing chain.
Working closely with external and internal customers, we succeeded in making major contributions and providing key impetuses in the year under review.
Analytical examination methods must provide meaningful and accurate results to enable effective evaluation of milk and milk products. Measuring accuracy is continually being improved, and new methods are being developed, for example to identify natamycine and lysozyme in cheese and to determine clostridii in milk. For the first time, Switzerland conducted a national sampling campaign for the systematic microbiological control of milk products. We contributed to this programme by providing our expertise in the elaboration and evaluation of the findings, and in transferring the knowledge acquired. In the last year we built and introduced a system to evaluate food safety in milk processing operations. This has proved an effective aid for official quality assurance inspections. We provided important impetuses for revising quality controls of commercial milk and formulated key principles in conjunction with all the involved parties.
Many milk products are obtained as a result of controlled fermentation processes. FAM offers the dairy sector a broad range of fermentation organisms which are regularly examined and adapted to customers' needs. In the year under review, the range of "bud"-label biocultures was expanded and a special culture for the production of Gruyere AOC was added to our range.
Evaluation of food safety in milk processing operations
Daniel Gerber
Daniel.gerber@alp.admin.ch
During its quality assurance (QA) inspections, the Dairy Inspection and Advisory Service (DIAS) assesses the general risks to product safety in milk processing operations. The new system introduced by FAM in the summer of 2003 improves transparency in terms of risks and traceability in the dairy sector.
Following every inspection of milk processing operations, compliance with all the criteria defined by QA directives is recorded and rated under four categories. The arithmetic mean of all four ratings gives the overall risk. The result and evaluation provide an effective indication of the risk category to which each milk processing establishment must be assigned. Regular calculation of the overall risk offers major benefits:
The results provide a guideline for determining the frequency of inspection for each establishment.
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The risk rating provides inspectors with a simple tool that can be used in all categories of establishment and is easy to communicate. Acceptance is high among all parties involved.
The overall risk rating for milk processing establishments is a national standard that enables informative statistical statements on the safety of Swiss milk and milk producers. This nation- wide overview is a useful benchmark not only for consumers as well as cantonal and national authorities, but also to the milk processing sector, since it substantially contributes to milk and milk product safety and promotes consumer protection.
All FAM lactic acid starter cultures are "bud"-label quality
Fritz Schaller
Deborah.rollier@alp.admin.ch
The research station for milk production offered customers lactic bacterial cultures with the
"bud" label for the first time in 2001. The range covers five biocultures for cheese manufacture, two for bio-yoghurt, and one for bio sour milk products. The other lactic acid starter cultures were produced using an anti-foam agent that was not accepted by BIO SUISSE, the accrediting authority for the "bud" label. After a lengthy search for alternatives, we finally found a suitable anti- foam agent. The agent had no negative effect on the manufacture and activity of the cultures, and in a cheese trial based on cultures manufactured with old or new anti-foam agents, no difference was identified either in the lactic acid fermentation or in the cheese quality.
In the autumn of 2003 BIO SUISSE awarded us the "bud" licence for 19 additional lactic acid starter cultures, production and delivery of which began on 1.1.2004 Now we are able to offer customers all 27 lactic acid starter cultures in "bud" quality, with a view to covering the full range of requirements for bio cheese, bio sour milk and bio yoghurt.
The research station for milk production offered customers lactic bacterial cultures with the "bud" label for the first time in 2001.
The future aim is to extend the "bud" quality label to remaining culture groups such as hole- forming propionic acid bacteria, lactic acid bacteria that inhibit secondary fermentation, and surface cultures. After all, the principle on which biological food production and processing is founded is closely linked with the principles adopted by Swiss cheese makers and marketers: to distribute natural, carefully processed milk products and, in so doing, avoid the use of genetic engineering and unnecessary additives.
Effects of geographical origins of samples on the measurement uncertainty of infrared milk analyses
Werner Luginbühl and Agathe Liniger Werner.luginbuehl@alp.admin.ch
The accuracy of infrared (IR) spectrometry of the principal components of raw milk (fat, protein and lactose) is largely dependent on the calibration quality. In addition to recombined calibration samples, good calibration must also incorporate native raw milk samples. Whether the incorporation of raw milk samples from the laboratory's catchment area ("regional" samples) in equipment calibration positively affects the accuracy of IR analyses is currently unknown. French studies point in this direction, while German experts dispute the necessity of "regional" calibrations.
To determine whether this is the case for Switzerland, raw milk samples were obtained simultaneously from three regions in Switzerland (Moudon/VD; Uettligen/BE; Zihlschlacht/TG) and analysed for fat, protein and lactose content using reference methods as well as IR spectrometry. The differences between the reference and IR results were statistically examined for significant effects of the
"regional" factor. In keeping with the French findings, the geographical origin of samples was found to have a significant effect on the accuracy of IR spectrometric results for fat and lactose but not for protein. This is probably due to differences in the mean molecular mass of fatty acids in milk fat, different levels of non-protein nitrogen and differences in the citrate content. Hence a minimum (systematic) measurement uncertainty can be achieved in the IR analysis of raw milk only if a sufficient number of "regional" calibration samples taken from the laboratory's catchment area are included in IR spectrometer calibration.
Chemical-microbiological method for the quantitative determination of
Clostridium tyrobutyricum spores in milkDeborah Shar, Marc dalla Torre, René Badertscher, Marie-Louise Geisinger and Priska Noth Marc.dalla-torre@alp.admin.ch
The bacteria Clostridium (C.) tyrobutyricum occasionally causes severe problems during the manufacture of hard and semi-hard cheese. Even minute quantities of spores are capable of triggering a defect. Problems arise mainly during winter production, as a result of increased silage feeding. Contaminated fodder and poor silage conditions (insufficient level of density) result in high levels of spores in silage. Poor milking and stall hygiene also cause high levels of clostridii in milk.
Figure 8: Typical chromatograph of a sample of skimmed milk with C. tyrobutyricum spores (C4 = butter acid)
There is therefore keen interest in methods of detecting the bacteria even in minute quantities.
Modified Agar RCM (Reinforced Clostridial Medium) filtration has been the method of choice to date. However, since it has
a detection limit of 25 spores/liter, an alternative quantitative method for detecting C. tyrobutyricum
