Presence of Listeria spp. in fish samples, fish products and sea products

Abstract

Listeria monocytogenes is a bacterium that is pathogenic for man and for most animal species. Listeriosis is a generalized infection that starts after ingestion of the causative agent L. monocytogenes (Finlay, 2001). Food that is not properly thermically processed, long storage of such food, food that is produced in inadequate hygienic food plants, as well as cooked-cooled ready to eat food (RTE) is the ideal medium for listeria multiplication. High risk food originated from fish, fish products and sea products comprised of: molluscs (fresh of frozen shellfish, crustaceans shelled or not), fresh fish (ready to eat without cooking), fish products packed with brine (NaCl<6%), (salted, marinated, fermented, cold smoked and fish in brine), thermically treated fish and crustacean products (pasteurization, cooking, hot smoking, including pre-cooking and panning). In this research, fish samples, fish products and sea products from Serbian markets were examinated such as: fresh fish (cooled), frozen food (fish and sea products - cuttlefish, squid, octopus, shellfish, crustaceans and shrimps), panned products; smoked fish, salted fish, thermally treated fish and fish products, semi-canned fish and canned fish. Microbiological testing has been performed according to internationally prescribed standards ISO 11290-1 (1996) "Microbiology of food and animal feed stuffs - Horizontal method for the detection and enumeration of Listeria monocytogenes". There were 470 samples from fish products and sea products. Presence of Listeria spp was registered in 58 samples (12.34%). Listeria monocytogenes was found in 1.92% samples (9 isolates), which makes 15.52% of the total Listeria that were isolated from the tested food. Other isolated Listeria belong to the following species: L. innocua (8.51%), L.welshimeri (1.28%), L.welshimeri/innocua (0.21%), L. grayi (0.21%) and L. seeligeri (0.21%). Exceptional viability of Listeria monocytogenes in the food tested was documented, also (freezing temperature - 18oC, five months)

Prevalence and molecular characterization of Listeria spp. and Listeria monocytogenes isolated from fish, shrimp, and cooked ready-to-eat (RTE) aquatic products in Iran

“…in raw fish and shrimp samples, recently reviewed in Jami, Ghanbari, Zunabovic, Domig, and Kneifel (2014). In these reports, the rate of L. monocytogenes contamination in raw fish and shrimp samples ranged from 43.3% (Chen et al, 2010) to 0% (Kuzmanovi c et al, 2011;Minami et al, 2010;Wang, Chern, Li, Yan, & Hsieh, 2012).…”

A review of the presence of some food contaminants on the territory of the Republic of Serbia

“…were also identified in 12% of 470 samples of fresh, frozen, salted, smoked and thermally processed fish and seafood. In this investigation, L. monocytogenes was present in 2% of the samples [21].…”

Comparative microbiological analysis of four different sea fishes collected from local market in Dhaka Metropolis

“…Frozen fish are prone to contaminated by Listeria spp. (Reij et al, 2004;Jelena et al, 2011). Previously several studies showed that some thermostable enterotoxin of Staphylococcus aureus and Escherichia coli would not destroy completely even after cooking of seafood or if the food cooked properly, due to improper handling recontamination can take place and consumption of this type of food causes severe food poisoning (Ayulo et al, 1994;Vieira et al, 2001;Omeo et al, 2005;Simon and Sanjeev, 2007;Beleneva, 2011;Tango et al, 2015).…”