Abstract
During the last years farm marketing has significantly increased. The present study deals with the bacteriological-hygienic quality, particularly with pathogenic microorganisms of raw milk and raw milk products from farm marketing. 709 samples of raw milk and raw milk products were collected nationwide. Certified milk (a kind of raw certified grade A milk), ex-farm milk, raw milk cheeses (soft cheese, semihard and hard cheese) and other products made of raw milk underwent quality checks for Listeria monocytogenes (L. mono-cyto-genes), Bacillus cereus (B. cereus), Verotoxin-producing Escherichia coli (VTEC), Salmonella spp. and Campylobacter jejuni (C. jejuni). Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and coliforms, which were valuated as hygienic pa-rameters according to the milk regulations 1995 (Milk Ordinance ?95), were checked. The total bacterial count (TBC) and somatic cells of certified milk and raw milk were deter-mined. Pursuant to the Milk Ordinance ?95 raw milk cheese was investigated for staphylo-coccal enterotoxins. 35 strains of B. cereus isolated from raw milk and raw milk products were examined for cytotoxicity. 21 raw milk products were examined for heat-stable (ST) and heat-labile enterotoxin (LT).
12 of 74 bulk milk samples from farms producing certified milk contained L. mono-cytogenes. However, all the 12 L. monocytogenes positive samples came from one and the same farm of the 35 farms producing certified milk. The fact that the certified milk of this farm was sold over a longer period gives cause for concern. 54 % of the samples contained S. aureus, 59,5 % E. coli and 87,8 % coliforms. In 17 % or 22 % of the cases, the counts of S. aureus or coliforms exceeded the threshold value "M" stipulated in the Milk Ordinance.
10 % of 149 bulk milk samples from farms selling raw milk were contaminated with L. mo-no-cytogenes, 8 % with B. cereus, 0,7 % each with VTEC and C. jejuni as well as 47 % with S. aureus. More than 80 % of the samples contained E. coli and coliforms.
In 22,8 % and in more than 80 % of 35 raw milk fresh cheese samples respectively S. aureus or E. coli as well as coliforms could be detected.
In 2,2 % of the samples from 89 raw milk soft cheeses L. monocytogenes was isolated. 5,6 % contained B. cereus and 2,4 % VTEC. In 28,1 % or in over 90 % of these products respectively S. aureus or E. coli as well as coliforms were detected.
2,0 % of the 245 semihard and hard cheese samples were contaminated with L. monocytogenes, 15,1 % with B. cereus and 1,4 % with VTEC. 31,4 % or more than 90 % of the samples respectively contained S. aureus or E. coli and coliforms.
All the VTEC serotypes in the present study have already been isolated in connection with human diseases.
Neither LT-, ST-enterotoxins nor S. aureus toxins could be detected in the subsequently analyzed products.
71,4 % of the 35 analyzed B. cereus strains showed cytotoxic activity.
The results of the present study show that part of the raw milk and raw milk products from farm marketing offered to the consumers do not fulfil the requirements of the food hygienic standards. Basically, the occurrence of pathogenic microorganisms in raw milk and raw milk products has even to be expected, to a smaller or larger extent. Thus there exists a health risk for the consumer.
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