Journal
JOURNAL OF FOOD PROTECTION
Volume 80, Issue 2, Pages 271-278Publisher
INT ASSOC FOOD PROTECTION
DOI: 10.4315/0362-028X.JFP-15-599
Keywords
Listeria monocytogenes; Manufacturer; Pulsed-field gel electrophoresis; Retail; Serotyping; Smoked salmon
Funding
- EU [2010/678/EU]
Ask authors/readers for more resources
Seven hundred seventy-eight samples of packaged smoked fish (774 smoked salmon and 4 smoked swordfish) on sale in Italy, from 50 different manufacturers located in 12 European Union countries, were purchased from the Italian market between May and December 2011. The surface temperatures of the samples on sale ranged from 0 to 130 degrees C (3.4 +/- 1.5 degrees C, mean +/- SD). Six hundred eighty (87.4%) of 778 samples were stored at <= 4 degrees C. One hundred fifty-seven samples (20.2%, 95% confidence interval 17.5 to 23.1%) were contaminated by Listeria monocytogenes, with 26 samples (3.3%, 95% confidence interval 2.3 to 4.8%) at levels >100 CFU/g. The maximum level of contamination was 1.3 X 10(6) CFU/g. The differences in the level of contamination of smoked fish between countries (chi(2) = 91.54, P < 0.05) and manufacturers (chi(2) = 193.22, P < 0.05) were significant. The frequency of detection for products from different manufacturing premises ranged from 0 to 76.9%. Serotyping by serological agglutination revealed that the main serotypes detected were 1/2a (65.3%) and 1/2b (22.4%). Pulsed-field gel electrophoresis typing with restriction enzymes AscI and ApaI yielded 36 pulsotypes from 144 isolates, clustering into 17 groups. Eight main pulsotypes accounted for 70.8% of the isolates. Three of the main pulsotypes were exclusively from products of a single manufacturer. In general, products from the same manufacturer showed genetic homogeneity, with one strongly prevalent pulsotype. Different manufacturers usually showed very different levels of contamination of the final product, confirming the importance of the management of process hygiene for controlling L. monocytogenes contamination.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available