Varianzanalytische Untersuchungen zur mikrobiologischen Beschaffenheit von gewolftem Rinderhackfleisch

Between March 1993 and December 2000 a total of 12,542 samples of industrially produced minced beef have been examined microbiologically. The analysis of variance included year (1993 to 2000), season (winter, spring, summer or autumn), meat parts and meat temperatures (lean beef fresh or frozen or fat beef fresh or frozen), duration of storage (0, 1, 2 or 3 days), meat supplier (36 suppliers), operation category (integrated slaughtering and deboning plant or deboning plant with purchased goods) and country of origin as factors of influence. The means were 4.68 lg cfu/g for total viable counts, 1. 91 lg cfu/g for coagulase-positive staphylococci and 2.48 lg cfu/g for enterobacteriaceae. Coagulase-positive staphylococci were found in 9.9%, salmonellae only in 0.36% of the samples. The investigations were carried out over a period of 8 years, during which a steady decrease for total viable counts (-0.59 lg) and for enterobacteriaceae (-0.89 lg) took place. In contrary, staphylococci counts and salmonellae detection rates remained rather constant over the whole period. Analysis of variance revealed significant effects for the factors "year", "season", "meat parts", "meat temperatures", "meat supplier" and "operation category" on the total viable counts and on the counts of enterobacteriaceae. "Meat suppliers" caused also significant differences in the content of staphylococci. During the 8 years of the study, the microbiological quality of minced meat (total viable counts and enterobacteriaceae) was steadily improved which was mostly based on the quality of the raw material and therefore on the in-plant hygiene management of the supplier.