Microbiological quality of curd cheeses and curd cheese preparations from the German market.

In the year 2007, curd (cream) cheeses and curd cheese preparations (n=125), all made from pasteurized milk, were purchased from German retail shops. These samples were analysed for several parameter describing their microbiological quality (Enterobacteriaceae, coliforms, E. coli, coagulase-positive staphylococci, Listeria monocytogenes). The qualitative detection of Enterobacteriaceae gave positive results for 44 % of the samples. Coliform bacteria were found in 33 % of the samples. However, the number of coliforms was usually low (< 10 2 cfu/g) in most samples, the maximum number was 3.4 x 10 4 cfu/g. Enterobacteriaceae and coliform bacteria were more frequent in cheeses and cheese preparations obtained as open slices compared with prepacked products. Furthermore, curd cheese preparations containing other ingredients (paprika, tomato, spices) were more frequently contaminated with Enterobacteriaceae or coliform bacteria than plain curd cheese. The most abundant Enterobacteriaceae species were Enterobacter cloacae (found in 30 % of the samples), Klebsiella pneumoniae ssp. pneumoniae (19 %), Escherichia coli (14 %), Serratia liquefaciens, Pantoea agglomerans (both 13 %), and Klebsiella oxytoca (10 %). E. coli was identified in 17 samples, the maximum value was 9.5 x 10 1 cfu/g. Listeria monocytogenes was not detected in any sample. Coagulase-positive staphylococci were detected in one sample only (4.0 x 10 1 cfu/g). In general, the microbiological quality of the examined curd cheeses and curd cheese preparations was satisfactory. The detection of coliform bacteria, as well as the detection of Enterobacteriaceae are both suitable parameters to estimate the microbiological quality of curd cheese (preparations), although none of these parameters is currently regulated within the European Union.