Prevalence of Foodborne Pathogens in Freshwater Fish in Latvia (original) (raw)
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Italian Journal of Food Safety
Cold smoked salmon products (belly flaps, pieces, fillet, and loin) obtained from the retail market in Lithuania were tested for the presence of L. monocytogenes. It was found that contamination of the cold smoked fish products with Listeria spp. depends on the type of the product. Contamination with listeria in salmon belly flaps was 7.5 times higher than in the loin (P<0.05), 1.8 times higher than in the pieces (P<0.05) and 30 times higher than in the fillet (P<0.05). Microbiological analysis showed that 32.5% (P<0.05) of the fish product samples were infected with L. monocytogenes, while multiplex PCR confirmed 31.25% positive samples (P<0.01). According to the study results, L. monocytogenes strains were divided into two serotypes: 4b (94.6%) and 1/2a (5.4%). High contamination of the products with Listeria spp. showed that cold smoked salmon products, sold in local market, can be a reason of human listeriosis in Lithuania.
Incidence of foodborne pathogens on European fish
Food Control, 2001
Fresh ®sh from France, Great Britain and Portugal were examined for the pathogens Aeromonas hydrophila, Clostridium botulinum, Listeria monocytogenes, Salmonella spp., Vibrio parahaemolyticus and Yersinia enterocolitica, whilst ®sh from Greece were examined for A. hydrophila, Cl. botulinum and V. parahaemolyticus only. Cl. botulinum and Salmonella spp. were not detected from any of the samples examined. L. monocytogenes was detected from trout and Y. enterocolitica from both salmon and trout in Great Britain but neither were detected in samples from France or Portugal. A. hydrophila was detected from all sites, with an overall incidence of 40%, whilst V. parahaemolyticus was detected in samples from Portugal (35%) and Greece (14%) but not in those from Great Britain or France.
Occurrence of Listeria Monocytogenes in a Serbian Salmon and Seafood Processing Line During 2013
Procedia Food Science, 2015
The objective of this study was to examine the occurrence of L. monocytogenes in a selected fish and seafood processing line. Results showed that during 2013, 12.4 %, 8.3 % and 2.3 % of fish, seafood salads and environmental swabs were positive for L. monocytogenes. All positive food samples showed a contamination level below 100 CFU/g. Environmental swabs from surface of slicing and trimming tables, slicing machines, fish filleting and trimming knives, belt glazer and working table were positive for L. monocytogenes. Therefore, strict attention must be paid to cleaning and disinfection to control the level of L. monocytogenes.
Major foodborne pathogens in fish and fish products: a review
Annals of Microbiology, 2015
Fish plays an important role in the human diet, and there is an observed increase in the consumption of fish per capita in Europe. However, intensive growth of industry and agriculture may cause contamination of natural and humanmade aquatic environments, and may affect not only the health of fish, but also raise safety concerns with regard to fish used for human consumption. It is well known that fish and fish products are often associated with human diseases. Thus, it is necessary to study the prevalence of pathogens in fish to ensure the safety of fish products and environments. Microbial assessment of fish also gives additional information about the hygienic status of environments, including lakes, rivers, ponds, and fish farms. Detection of pathogenic microorganisms or changes in natural microflora in the water environment could be an important indicator of possible contamination. The aim of this review was to describe and discuss the five most relevant bacterial genera and species linked to aquatic environments-Vibrio spp., Listeria monocytogenes, Yersinia spp., pathogenic Salmonella serovars, and Clostridium botulinum-causing human foodborne diseases.
Veterinary World, 2014
Aim: In the current study, a contribution to the knowledge on the prevalence and level of contamination of Listeria monocytogenes in ready-to-eat (RTE) seafood marketed in Thessaloniki (Northern Greece) was provided; the serovar identity of the L. monocytogenes isolates was also determined. Materials and Methods: A total of 132 RTE seafood samples consisting of 74 smoked fish products, 18 salted fish products, 16 dried fish products, 9 raw marinated fish products, 10 cooked marinated cephalopods and 5 surimi crab stick products were analyzed. L. monocytogenes were isolated and enumerated based on ISO 11290-1/A1 and ISO 11290-2/A1 protocols, respectively, and identified using a multiplex polymerase chain reaction (PCR) system utilizing genus and species specific primers. For the identification of serotypes a second multiplex PCR assay was used which clusters L. monocytogenes strains into four major serogroups. Results: Of the samples examined, 11 (8.3%) proved positive for Listeria spp. with 8 (6.1%) yielding L. monocytogenes. Only in one sample of smoked mackerel the level of L. monocytogenes exceeded the legal safety limit of 100 cfu/g set out in Commission Regulation (EC) No. 1441/2007. Serotyping showed higher percentages of isolates belonging to PCR serogroup 3:1/2b, 3b, 7 (46.7%) and serogroup 1:1/2a, 3a (40%) followed by serogroup 4:4b, 4d, 4e (13.3%). Conclusion: This study demonstrated that L. monocytogenes can be isolated from processed RTE seafood products at retail in Thessaloniki (Northern Greece) in low concentrations. However, the presence of this human pathogen in RTE seafood should not be overlooked, but it should be considered as having significance public health implications, particularly among the persons who are at greater risk. Therefore, RTE seafood should be produced under appropriate hygienic and technological conditions since the product does not undergo any treatment before consumption.
International journal of food microbiology, 2006
This study focused on the ecology of Listeria monocytogenes in a fish farm by following the changes in its occurrence in different types of samples for a three year period. In addition, L. monocytogenes isolates from different seafood industry areas were compared with pulsed field gel electrophoresis (PFGE) typing to discover possible associations between primary production, further processing and final products. Weather conditions were found to have a strong influence on the probability of finding Listeria spp. in a fish farm environment. The number of samples contaminated with Listeria spp. was typically bigger after rainy periods. Brook and river waters as well as other runoff waters seemed to be the main contamination source at the farm studied. The farmed fish originally found to carry L. monocytogenes become gradually Listeria free. The time needed for the purification of the fish was several months. The sea bottom soil samples were the ones that preserved the L. monocytogenes contamination the longest time. It can be stated that the fish and fish farm equipment studied did not spread listeria contamination. On the contrary, they were found to suffer from listeria contamination coming from outside sources like the brook water. There was a wide range of different L. monocytogenes PFGE-pulsotypes (30) found at 15 Finnish fish farms and fish processing factories. L. monocytogenes isolates from the final products often belonged to the same pulsotypes as did the isolates from the processing environment as well as from the raw fish. This suggests that, in addition to the fish processing factory environment, the fish raw materials are important sources of L. monocytogenes contamination in final products.
Pulsed-Field Gel Electrophoresis Typing of Listeria monocytogenes Isolated in Two Finnish Fish Farms
Journal of Food Protection, 2006
The aim of this study was to find sources of Listeria monocytogenes contamination in fish products from a fish farm. The occurrence of L. monocytogenes also was compared in two freshwater fish farms with different types of fishponds. Samples collected from chilled rainbow trout (Oncorhynchus mykiss) and the slaughterhouse environment did not contain L. monocytogenes, but Listeria innocua was found in two samples from the slaughterhouses. Ten isolates of L. monocytogenes were discovered in sediment and water samples from farming tanks and earth ponds. Further characterization by serovar revealed the same serovar (1/2a) for all the isolates. Pulsed-field gel electrophoresis was used to divide the isolates into five different pulsotypes, three of which have been identified previously in fish products on the retail market. This finding supports the assumption that the primary production, and probably the raw fish, is a source of Listeria contamination in fish products. Some of the isola...
The occurrence of Listeria spp. and Salmonella spp. in surface waters
Microbiological Research, 1997
Listeria ssp., mainly Listeria monocytogenes as well as Salmonella spp. are recognized as significant human pathogens. The purpose of this study was to examine the occurrence of Listeria spp. and Salmonella spp. in surface waters of Northem Greece and to investigate the correlation of these pathogens with the standard indicator bacteria.
International Journal of Food Microbiology, 1995
A smoked salmon processing plant including a smokehouse and a slaughterhouse was examined for the occurrence of Listeria monocytogenes and other Listeria spp. From a total of 47.5 samples the overall frequency of L. monocytogenes was 16%, while other Listeria spp. were found in 22% of the samples. L. monoqtogenes was most often detected in samples from the smokehouse, where 29% of the environmental and 26% of the fish samples during processing contained the bacteria. 17% of the fish raw material to the smokehouse were contaminated, while 11% of the samples from vacuum-packed smoked salmon were positive for L. monocytogenes. The slaughterhouse was sporadically contaminated, but L. monocytogenes was not found in 50 samples of slaughtered fish. L. monocytogenes was found in the seawater outside the slaughterhouse. Multilocus enzyme electrophoresis divided the isolated L. monocytogenes strains into 11 electrophoretic types (ETs). One ET, ET-6, which is the most common ET in Norway, seemed to have colonized the smokelhouse. Isolates from the seawater, from the slaughterhouse and from fish coming into the smokehouse, before filleting, were other ETs.
Food Science and Technology International, 1998
Salmon-trout ( Onchorhyncus mykiss) and salmon ( Salmo salar) are the main raw materials in the cold-smoked fish industry. It is important to prevent the contamination of these ready-to-eat products with Listeria monocytogenes and other ( Listeria spp.) because the temperature used in the cold-smoking process is not sufficient to inactivate these organisms. The presence of Listeria spp. and L. monocytogenes in the cold-smoked salmon and salmon-trout processing chains of three Portuguese factories examined was already confirmed in previous studies. Thus, it was important to ascertain the possible sources of contamination, the raw material being the most important one. All the Portuguese cold-smoking fish factories use fresh salmon-trout from two trout farms in the north of Portugal and Norwegian salmon which arrives by lorry every week under refrigeration, imported always by the same company; 88 samples of salmon and salmon-trout were analysed; 67 environmental samples from the two t...