Listeria monocytogenes in ready-made food consumption: An analysis of the official tests in Switzerland the years 2006-2008 [Listeria monocytogenes in genussfertigen Lebensmitteln: Eine Auswertung der amtlichen Untersuchungen in der Schweiz der Jahre 2006-2008]

In the years 2006-2008, 13. 978 ready-to-eat foodstuffs were tested by official laboratories of food control in Switzerland for compliance with legal limits for Listeria monocytogenes. Totally, the pathogen could be detected in 67 foods (0,5 % of all samples). Most frequently, raw meat cured sausages (proportion of positive samples 3,9 %) were contaminated followed by smoked fishes (1,4 %) and semi-hard cheeses (1,1 %). For soft cheese, a rather low contamination frequency of 0,3 % was shown. Quantification of L. monocytogenes was possible in 18 ready-to-eat foods from the market and six out of them showed high counts of >1. 000 CFU per gram. Concerned were a sandwich with smoked salmon and other components (250. 000 CFU/g), smoked salmon (180. 000 CFU/g), smoked trout (13. 000 CFU/g), semi-hard cheese (9. 200 CFU/g) and salami (5. 500 and 1. 850 CFU/g). In connection with cases of listeriosis, the highest measured count (5 × 107 CFU/ml) was found in liquid cream of a private household where it was probably contaminated and not adequately stored. Surprisingly, in 931 desserts and confectioneries, in 384 ice-creams, in 3. 567 pre-cooked foods and in 806 samples of raw fruits or vegetables, L. monocytogenes was never isolated and in 720 delicatessen salads only once (Celery salad with <100 CFU/g). The evaluation of a high number of laboratory data allowed identifying the current focal points of risk, an information which is important for a risk-based design of future control activities. © 2013 Bundesamt für Verbraucherschutz und Lebensmittelsicherheit (BVL).