Occurrence of L. monocytogenes in ready-to-eat poultry products available on the German market

Abstract

Listeria monocytogenes, an important foodborne pathogen, is of great concern especially for the ready-to-eat (RTE) food industry. The purpose of the study was to determine the number of L. monocytogenes in 300 RTE poultry products at their shelf-life expiry date. The samples were examined following the ISO 11290-2:2005 protocol. Overall, 6% and 3% of the analyzed products were positive for Listeria spp. and L. monocytogenes, respectively. The occurrence of L. monocytogenes was significantly (p<0.05) higher in raw RTE poultry products than in heat treated RTE poultry products. The contamination level of L. monocytogenes was <10cfu/g in 94%, between 10 and 100cfu/g in 3% and >100cfu/g in 1% of the samples. L. monocytogenes were isolated from products of various lots from 3 out of 7 manufacturers. All 18 L. monocytogenes belonged to serotype 1/2a and among the isolates only two PFGE patterns were obtained, indicating a common contamination source. This is the first study that surveyed the number of L. monocytogenes in RTE poultry products at the end of their shelf-life. The high frequency of L. monocytogenes found in frankfurters and raw spreadable sausages underlines the need for food manufacturers to regularly control L. monocytogenes in the food processing environment. Consumers should nevertheless be cautious when handling these products. Since poultry products are becoming more and more popular for consumers, regular monitoring is necessary to track the occurrence of the pathogen in RTE poultry products.