[The microbiological status of dry sausage in East Netherlands]. / De microbiologische gesteldheid van droge worst in Oost-Nederland.

Dry fermented sausage (dfs) was the food most suspected in a number of outbreaks of salmonellosis and staphylococcal enterotoxaemia. Data on formulation and processing showed that over 75 per cent of 76 producers still manufactured dfs in a traditional manner: fermentation and drying at ambient temperature for ten days on an average, green room facilities not present. 'Modern' processes were characterised by fermentation in green rooms at elevated temperatures, thus limiting production time to six days on an average. However, precautions to prevent luxurious growth of S. aureus under these conditions were not adopted to any appreciable extent. Consequently, high S. aureus levels (greater than 10(4) cfu/g) were detected precisely in dfs from five manufacturers using rapid processes. Colony counts of Enterobacteriaceae were low in dfs (81 per cent of 151 samples less than 10(3) cfu/g), associated with relatively low pH and aw levels and a high concentration of salt. However, Salmonella was detected in 16 (11%) of the samples, both from 'traditional' and 'modern' producers. Improvement of manufacturing practices in the manufacture of dfs should be stimulated to guarantee wholesome and safe products.

[Developments in veterinary medicine and possible impact on veterinary practice and education]. / De ontwikkelingen in de diergeneeskunde en de mogelijke gevolgen voor de beroepsuitoefening en de opleiding.

What are the recent developments in the various fields of the veterinary profession and which adjustments in veterinary medicine are required for successful anticipation to these new conditions? Efforts are made to answer these questions from the point of view of each of the authors' professional disciplines. The authors all specialised in different fields of veterinary medicine. The present paper is a summary of each of the authors' editorial contributions on this subject as published in Fakulteitsnieuws (magazine of the Utrecht Faculty of Veterinary Medicine) in 1984 and 1985. Veterinary practice is found to be developing into two main directions: (i) veterinary medicine of pet animals which concentrates on the individual diseased animal and (ii) veterinary medicine of farm animals in which herd health control and preventive medicine are increasingly emphasized. In addition, industry has an increasing need for veterinarians having a specific veterinary pathobiological background. Optimum veterinary care requires veterinarians increasingly to concentrate on one of these (sub)disciplines. This implies that, in veterinary training, students should be afforded ample opportunity to achieve depth in the areas of personal interest. This is made possible by ensuring further differentiation in the veterinary curriculum and by setting up an intensive system of post-graduate education.

Prevalence of Campylobacter jejuni and Salmonella during pig slaughtering.

It was found that 79% of healthy pigs, slaughtered in three different slaughterhouses in the Netherlands, were intestinal carriers of Campylobacter jejuni (mean number 4000 cfu per g), and 21% of the same pigs had Salmonella in the intestinal tract (mean number 10 cfu per g). Immediately after slaughter, Campylobacter was swabbed from 9% of the carcasses and Salmonella from 13%. It is concluded from these data that most of the contamination on carcasses does not originate directly from the intestinal tracts of the animals but rather from surfaces, equipment, and utensils in the slaughter hall. It was demonstrated that Salmonella could survive in the slaughter hall, whereas Campylobacter died off, probably due to its vulnerability to drying conditions and its inability to grow at temperatures below 30 degrees C. Campylobacter was not isolated from the carcasses after cooling. It had been shown earlier that this again was caused by dry conditions, brought about by the use of forced ventilation in the cooling rooms. In an additional investigation, Campylobacter was not isolated from 248 samples of minced pork (10 g each), whereas Salmonella was found in 13% of these samples.

Survival of Campylobacter jejuni during Poultry Processing and Pig Slaughtering.

Experiments were done to assess the survival of Campylobacter jejuni during different stages of poultry processing and pig slaughtering. Natural sources of Campylobacter contamination, i.e., spinchiller water, chicken intestinal contents and pig feces, were used for this purpose. C. jejuni in chicken intestinal contents had D-values ranging from 0.18 to 0.39 min at 60°C to 1.96 to 10.82 min at 52°C. Experiments with surfaces of pig carcasses contaminated with pig feces and held in the cooling room of a pig slaughterhouse showed an overnight reduction of Campylobacter until below the detection level. Further experiments in the laboratory showed that this reduction was due to drying of the skin surface. C. jejuni was very sensitive to drying. When contaminated spinchiller water was spread on tiles of different materials (aluminium, stainless steel, Formica and ceramic), the organism survived as long as a moistened surface could be observed. They could not be isolated once surfaces were visually dry. Freezing affected C. jejuni only during the first few hours; after an initial drop of number, Campylobacter could survive on chicken carcasses and chicken livers at -20°C for more than 64 and 84 d, respectively.