EN
The aim of this study was to evaluate the frequency of the occurrence of Listeria monocytogenes in food of animal origin in the Opole region in 2008-2010. Three types of food of animal origin were examined during the study: raw meat ready for direct consumption, heat-treated meat, and dairy products. All products came from production plants. In total, 1945 samples of meat and 634 samples of dairy products were examined. Studies were conducted in accordance with official standards [PN_EN ISO 11290-1:1999]. Listeria monocytogenes was isolated with different frequency from food of animal origin throughout the research period. The highest contamination (70-80%) was found in 2008-2009 in raw meat products ready for direct consumption. Listeria was isolated from samples taken in June and November (80%) 2008 and in May (100%) 2009. Significantly lower levels of contamination (4%) were found in heat-treated meat products. Listeria was mostly isolated from samples taken in August (20%) and December (15.40%) 2008, in February (12.50%) 2009 and in August (20%) and November (25%) 2010. It was never detected in heat-treated meat products in March, April and May, regardless of the year. In dairy products, L. monocytogenes was found only in 2009, in 2.32% of the samples tested in April and in 25% of the samples tested in December. The hygiene of raw meat production improved considerably in 2010, since Listeria was found only in 13% of products. In 2010, dairy products were free of L. monocytogenes.