microbiological and pathogenic contaminants of seafood in greece

MICROBIOLOGICAL AND PATHOGENIC CONTAMINANTS OFSEAFOOD IN GREECE

C. PAPADOPOULOU1,5, E. ECONOMOU1, G. ZAKAS1,2, C. SALAMOURA1,C. DONTOROU1,3 and J. APOSTOLOU1,4

1Food Microbiology Unit, Microbiology DepartmentMedical School, University of Ioannina Dourouti University Campus

45110 Ioannina, Greece

2Preveza Aquaculture StationMinistry of Agriculture

Preveza, Greece

3State Veterinary ServicePrefecture of Ioannina, Greece

4Regional Veterinary Laboratory ServiceMinistry of Agriculture

Ioannina, Greece

Accepted for Publication November 11, 2006

ABSTRACT

A total of 360 samples, including 105 marine fish, 25 prawns, 50 squid,50 octopus, 30 mussels and 100 freshwater fish were examined microbiologi-cally for the presence of microorganisms potentially pathogenic. All sampleswere examined following standard microbiological procedures. The isolatedmicroorganisms were: Aeromonas hydrophilia (38–93%), Klebsiella ozonae(1–40%), Escherichia coli (14–87%), Yersinia enterocolitica (0–40%), Hafniaalvei (0–36.6%), Enterobacter agglomerans (0–42%), Citrobacter freundii(0–46%), Proteus vulgaris (15–80%), Proteus mirabilis (7–82%), Morganellamorganii (0–30%), Pseudomonas fluorescens (0–34%), Pseudomonas putida(0–6%), Plesiomonas shigelloides (0–4%), Listeria innocua (1–3.3%), Vibrioparahaemolyticus (0–2%), Clostridium perfringens (0–1%), Staphylococcusaureus (0–80%) and Candida quillermondi (0–1%), Candida albicans (0–1%),Penicillium oxalicum (0–1%) and Penicillium italicum (0–12%).

5 Corresponding author. TEL: +3026510-97592; FAX: +3026510-93563; EMAIL: [email protected]

Journal of Food Quality 30 (2007) 28–42. All Rights Reserved.© 2007, The Author(s)Journal compilation © 2007, Blackwell Publishing

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PRACTICAL APPLICATIONS

Marine and fresh water fish used not to be considered important vectorsof human pathogens. However, this situation is changing, due to environmentalpollution and increasing animal densities as a consequence of a rapidlygrowing food industry and also due to increasing awareness by health careprofessionals on seafood pathogens that may cause human illness. The pres-ence of pathogenic microorganisms represents a safety concern, particularly ifseafood is eaten raw. In the present study, the presence of a wide range ofpathogens, most of which are associated with foodborne diseases, indicates thepotential health risks from contaminated seafood. Although most of the iso-lated genera are heat-labile and adequate cooking will inactivate them,improper handling and cross-contamination or raw seafood eating habits,might pose a health hazard, especially to susceptible population such as theimmunosupressed, children and the elderly.

INTRODUCTION

The recent food scares related to ruminant’s meat (bovine spongiformencephalitis [BSE], scrapie), chicken meat (Salmonellae, avian influenza,dioxins) and the dietary changes of the consumers toward healthier food habits(e.g., Mediterranean diet, sushi), has resulted in a rapid rise of seafood con-sumption worldwide (Wallace et al. 1999; Yasumoto 2000). However, asdemands for and production of seafood increased, it became important to paymore attention to seafood safety and seafood-related diseases. Although theywere problems previously regarded as local and insignificant, now it is wellknown that they can spread to other regions as a result of increasing worldtrade and environmental changes. Furthermore fish and shellfish are eaten rawin many cultures and this habit provides the opportunity for direct transmissionof pathogens. Contaminated seafood has been implicated in foodborne out-breaks in many countries (Jensen and Greenlees 1997; Lipp and Rose 1997;Wallace et al. 1999; Rocourt et al. 2000; Gillespie et al. 2001), the majority ofthem having been caused by bacteria, viruses, histamine and marine biotoxins.

Although there is some information on the incidence of various patho-gens on fish (Fricker and Tompsett 1989; Gobat and Jemmi 1993; Walker andBrooks 1993; Hanninen et al. 1997; Davies et al. 2001) the data provided areeither restricted to a few pathogens, or to a limited geographical area. Theobjective of this survey was to generate information on the prevalence ofpathogenic and potentially pathogenic microorganisms, which under suitableconditions may cause mild to severe public health problems.

29MICROBIOLOGICAL AND PATHOGENIC CONTAMINANTS

MATERIALS AND METHODS

Sampling

Within a period of 12 months (from August 2004 to August 2005) 360randomly collected samples were analyzed microbiologically.

There was a total number of 260 seafood samples examined counting 25from prawns (Penaeus kerathurus), 50 from squids (Loligo vulgaris), 50 fromoctopuses (Octapus vulgaris), 30 from mussels (Mytilus galloprovincialis) and105 from fresh marine fish including: sardines (Sardina pilchardus), plaices(Solea vulgaris), hakes (Merluccius merluccius), bogues (Boops boops), silversides (Atherina hespectus), mullets (Mugil cephalus) and mackerels (Scomberscomber, Scomber colias). Also a total number of 100 freshwater fish wereexamined. The freshwater fish samples were trout (Salmo truta), collectedfrom local fish retail stores. All samples were obtained from retail stores ofnorthwestern Greece and were of local capture (from the Ionian Sea). Thesamples were collected within 24 h of capture, placed into sterile containersand were transferred to the laboratory at 4C, using insulated transport boxes.The samples were either processed upon delivery to the laboratory or werepacked in sterile ice and stored inside a cold ward at 4C for 24 h prior to themicrobiological analysis.

Microbiological examination

All samples were analyzed for the following microbial pathogens: Vibriospp., Salmonella spp., Listeria spp., enteric indicator organisms (membersof the Enterobacteriacae family and Enterococci), Pseudomonas spp.,Clostridium perfringens, Staphylococcus spp., yeasts and moulds.

The microbiological procedures included the homogenization of 25 g ofeach sample (flesh from seafoods or fish flesh and skin), in 225 mL of appro-priate broth according to standard microbiological methods (ISO methods).The methods specifically used were: for Salmonella spp. the ISO 6579-6579(E); for Staphylococcus spp. the ISO 6888-1983 (E); for C. perfringens theISO 7937-1997 (E); for Enterobacteriacae, culture on violet red bile glucoseagar (VRBGA) according to ISO 7402-1993 (E); for Yersinia enterocoliticathe ISO 10273-1994 (E); for Enterococcus spp., culture according to method1 as described by Roberts et al. (1995); for Pseudomonas spp., culture accord-ing to method 3 as described by Roberts et al. (1995); for Vibrio spp., enrich-ment culture according to method 1 as described by Roberts et al. (1995); forListeria spp., pre-enrichment in half-Fraser broth and enrichment in Fraserbroth (FRASER Listeria Selective Enrichment Broth, Merck, Darmstadt,Germany) followed by cultures on to Oxford agar (OXFORD Listeria Selec-tive Agar Base, Merck) and PALCAM agar (PALCAM Listeria Selective Agar

30 C. PAPADOPOULOU ET AL.

Base, Merck) as recommended by ISO-10560-1999 (E); and for yeasts andmoulds, the ISO 7954-1987 (E) was employed. Identification of the bacteriaand yeast isolates to the species level was performed using the API-20E,API-NE, API-STAPH, API LISTERIA and API-CHAUX (bioMerieux, Marcyl’ Etoile, France). For moulds, species identification was based on the micro-scopic appearance and colony morphology.

RESULTS

The results are presented in Table 1. Concerning pathogens causingsevere infections, Salmonella spp. was not detected in any of the samplesexamined, V. parahaemolyticus was detected in two samples of fish (bogue andcod), Listeria innocua was detected from two samples (from mussels and rivertrout) and C. perfringens was detected in one sample of freshwater fish (trout).Aeromonas hydrophila was the most commonly isolated species, followed byP. vulgaris, P. mirabilis, Morganella morganii and other members of theEnterobacteriacae family. Plesiomonas shigelloides was isolated from bothmarine and freshwater fish. Yeasts and moulds were isolated only from fresh-water fish samples, with the exception of one strain of Candida isolated frommarine fish. Mussels were the most contaminated seafood, showing the highestfrequencies of Escherichia coli (100%), P. vulgaris (96%) and P. mirabilis(92%) isolations and harboring pathogens of public health importance suchas Y. enterocolitica (40%), Staphylococcus aureus (56.6%), Pseudomonasfluorescens (26.6%) and L. innocua (3.3%).

DISCUSSION

A. hydrophila, Pseudomonas spp., V. parahaemolyticus, most members ofthe enterobacteriacae family, Listeria spp., Yersinia spp. and S. aureus, areindigenous in aquatic environments and are found in large numbers particu-larly in polluted aquatic environments. Such species are expected to becommon fish contaminants and consist a potential food safety hazard; there-fore our results show that this is the case for most of the bacterial speciesisolated. However, the yeasts (Candida spp.) and moulds (Penicillium spp.)species isolated, especially the latter, are rather unusual to occur in the aquaticenvironment, and any foodborne transmission is yet to be proven orquestioned.

The high incidence of A. hydrophila isolations from almost all marine(93%) and freshwater fish (38%) and other seafood (78–86%) examined in this


TABLE 1.INCIDENCE OF MICROORGANISMS ISOLATED IN SEAFOOD AND SEAWATER

IN GREECE

Microorganism Incidence %(Number of positive samples/number of tested samples)

Bacteria Seafood Marine fish Freshwater fish

Aeromonas hydrophila 80.0 (20/25) prawns 93.0 (98/105) 38.0 (38/100)86.0 (43/50) squids78.0 (39/50) octopus73.3 (22/30) mussels

Proteus vulgaris 60.0 (15/25) prawns 45.0 (47/105) 15.0 (15/100)22.0 (11/50) squids26.0 (13/50) octopuses80.0 (24/30) mussels

Proteus mirabilis 32.0 (8/25) prawns 51.0 (54/105) 7.0 (7/100)26.0 (13/50) squids14.0 (7/50) octopuses76.6 (23/30) mussels

Pseudomonas fluorescens 0.0 (0/25) prawns 34.0 (36/105) 15.0 (15/100)8.0 (4/50) squids

10.0 (5/50) octopuses26.6 (8/30) mussels

Pseudomonas putida 0.0 (0/25) prawns 6.0 (6/105) 0.0 (0/100)0.0 (0/50) squids0.0 (0/50) octopuses0.0 (0/30) mussels

Plesiomonas shigelloides. 0.0 (0/25) prawns 4.0 (4/105) 2.0 (2/100)0.0 (0/50) squids0.0 (0/50) octopuses0.0 (0/30) mussels

Enterobacter agglomerans 8.0 (2/25) prawns 42.0 (44/105) 0.0 (0/100)2.0 (1/50) squids0.0 (0/50) octopuses

36.6 (11/30) musselsEscherichia coli 32.0 (8/25) prawns 87 (91/105) 14.0 (14/100)

6.0 (3/50) squids18.0 (9/50) octopuses83.3 (25/30) mussels

Citrobacter freundii 0.0 (0/25) prawns 46.0 (47/105) 1.0 (1/100)2.0 (1/50) squids4.0 (2/50) octopuses

33.3 (10/30) musselsMorganella morganii 0.0 (0/25) prawns 30.0 (31/105) 1.0 (1/100)

0.0 (0/50) squids0.0 (0/50) octopuses

20.0 (6/30) musselsKlebsiella ozonae 0.0 (0/25) prawns 40.0 (42/105) 2.0 (2/100)


40.0 (12/30) mussels


TABLE 1. CONTINUED

Microorganism Incidence %(Number of positive samples/number of tested samples)

Bacteria Seafood Marine fish Freshwater fish

Hafnia alvei 24.0 (6/25) prawns 20.0 (21/105) 1.0 (1/100)0.0 (0/50) squids4.0 (2/50) octopuses

36.6 (11/30) musselsYersinia enterocolitica 0.0 (0/25) prawns 10.0 (10/105) 0.0 (0/100)


40.0 (12/30) musselsSalmonella spp. 0.0 (0/25) prawns 0.0 (0/105) 0.0 (0/100)


Staphylococcus aureus 8.0 (2/25) prawns 80.0 (84/105) 6.0 (6/100)0.0 (0/50) squids0.0 (0/50) octopuses

56.6 (17/30) musselsVibrio parahaemolyticus 0.0 (0/25) prawns 2.0 (2/105) 0.0 (0/100)


Clostridium perfringens 0.0 (0/25) prawns 0.0 (0/105) 1.0 (1/100)0.0 (0/50) squids0.0 (0/50) octopuses0.0 (0/30) mussels

Listeria spp. 0.0 (0/25) prawns 0.0 (0/105) 1.0 (1/100)0.0 (0/50) squids0.0 (0/50) octopuses3.3 (1/30) mussels

Yeasts and mouldsCandida quillermondi 0.0 (0/25) prawns 0.0 (0/105) 1.0 (1/100)


Candida albicans 0.0 (0/25) prawns 1.0 (1/105) 0.0 (0/100)0.0 (0/50) squids0.0 (0/50) octopuses0.0 (0/30) mussels

Penicillium oxalicum 0.0 (0/25) prawns 0.0 (0/105) 1.0 (1/100)0.0 (0/50) squids0.0 (0/50) octopuses0.0 (0/30) mussels

Penicillium italicum 0.0 (0/25) prawns 0.0 (0/105) 1.0 (1/100)0.0 (0/50) squids0.0 (0/50) octopuses0.0 (0/30) mussels

Samples examined = 360 155 105 100


study, concurs with the results of other researchers in the U.K., New Zealand,Switzerland, Taiwan, Portugal, France and Greece (Fricker and Tompsett1989; Hudson et al. 1992; Gobat and Jemmi 1993; Tsai and Chen 1996;Hanninen et al. 1997; Davies et al. 2001), who have found incidences rangingfrom 19% to 90% in similar samples. Aeromonas species have been recog-nized as potential or emerging foodborne pathogens for more than 20 years,and A. hydrophila has been occasionally associated with foodborne disease,the clinical manifestations being either extraintestinal (sepsis, meningitis, peri-tonitis, endocarditis, pneumonia, ocular and urinary tract infections, septicarthritis, osteomyelitis and soft-tissue infections) or gastroenteritis (Hudsonet al. 1992; Kirov 1997; Isonhood and Drake 2002). Nevertheless, A. hydro-phila, like most aeromonads, is psychrotrophic, able to grow in foods duringcold storage, it is not resistant to food processing regimes and is readily killedby heat treatment, thus any risk of foodborne infection results from eating rawor undercooked seafood.

Ps. fluorescence (0–34%), Pseudomonas putida (0–6%) and Plesiomonasspp. (0–4%) were isolated from a small number of samples. Ps. fluorescenceand Ps. putida are common contaminants of both marine and freshwater fish,accounting for fish spoilage (Van Damme and Vandepitte 1980; Vandepitteet al. 1980; Gennari and Dragotto 1992; Gram 1993; Smolowitz et al. 1998;Tryfinopoulou et al. 2002). Plesiomonas shigelloides is a common pathogen intropical regions, but it is rarely isolated in temperate climates; it seems to beubiquitous in freshwater worldwide and may also cause invasive infections incold-climate areas. It is often isolated from surface water and fish, and hasbeen found to cause gastroenteritis. The course of infection is sometimesasymptomatic, but usually, patients develop an acute gastroenteritis, whileimmunocompromised patients can show serious courses of infection. Bacter-emia caused by P. shigelloides, although a rare event, is often associated withthe consumption of seafood and fresh or estuarine water in temperate ortropical climates. However most patients with bacteraemia have shown under-lying health disorders (Jonsson et al. 1997; Aldova et al. 1999; Aldova 2000;Knebel et al. 2001).

Various members of the Enterobacteriacae family can be found in theaquatic environment, some of them are recognized as indicator microorgan-isms of fecal pollution. E. coli and Proteus spp. are commonly isolated fromseafood. Therefore, Proteus species, E. coli and some other enteric bacterialike Morganella, Klebsiella, Hafnia, Enterobacter, Serratia and Citrobacterare important histamine-producing bacteria in fish with high free histidinecontent, especially in scombroid fish, and have been implicated in histaminefood poisoning (or scombroid poisoning) incidents (Taylor 1986; Ababouchet al. 1991; Rodriguez-Jerez et al. 1994). However, in the present surveyhistamine production was not studied.


Y. enterocolitica is an enteric pathogen associated with a wide range ofclinical and immunological signs and symptoms principally reported in chil-dren, but can occur in any age group. It is widely distributed in the environ-ment, and is more frequently isolated in temperate areas because of itspsychrotrophic nature enabling it to survive in the aquatic environment intemperatures as low as 0C. However, in the recent 12 years the organism hasbeen recognized as an emerging foodborne pathogen, next to Salmonella andCampylobacter (Lanser et al. 1993; Fenwick and McCarthy 1995), contami-nating a variety of food including seafood (Barton et al. 1997). Although theincidence of Y. enterocolitica isolation from fish has been found to be withinthe range of 0–23% (Hudson et al. 1992; Walker and Brooks 1993; Khareet al. 1996; Velazquez et al. 1996; Davies et al. 2001) and in our survey, from0–10% (freshwater fish and sea fish, reciprocally) to 40% (mussels), fishconsumption has not been the cause of any proven case of human yersiniosisyet.

Listeria spp. is a gram-positive, aerobic or microaerophilic rod, that hasbeen isolated from humans, a variety of animals, environmental (soil, water)samples, forages, fresh and ready-to-eat foods. The listeria species most fre-quently isolated from seafood are L. innocua, Listeria monocytogenes andListeria welshimeri, and the reported incidence ranges from 0–56%. L.innocua is the most common species encountered in fresh and cold-smokedsalmon, mussels, squids, mackerels and other seafood (Farber 1991; Dillonet al. 1992, 1994; Rorvik et al. 1995; Vaz-Velho et al. 1998, 2000; Laciarand Centorbi 2002). In our study, two strains (0.6%) of L. innocua wereisolated from mussels (3.3%) and trouts (1.0%). Although L. innocua isreferred as a nonpathogen for humans in microbiology textbooks, recently ithas been described in association with human disease. A case of fatal bac-teremia caused by L. innocua in a 62-year-old patient was reported in 2003in France (Perrin et al. 2003). This is not the only case of a nonpathogenturning into a pathogen; in clinical microbiology all microbes are consideredas “pathogens or potential pathogens” for humans. The phenomenon of non-pathogenic microorganisms turning into pathogens is attributed to theincreased ability of the microorganisms to adapt to new hosts and to theincreased numbers of immunosupressed or immunodeficient subjects whoare vulnerable to opportunistic infections. Isolates characterized as “non-pathogenic for humans” should be very carefully estimated in reports toregulatory agencies, especially those species that are already known to bepathogenic for animals.

Salmonella was not detected in any sample during this study. In similarstudies carried out by other researchers elsewhere, Salmonella has also notbeen isolated (D’Aoust et al. 1980; Belchior and Pucci 2000; Davies et al.2001) or has been occasionally isolated (Youssef et al. 1992). Salmonella is


not indigenous to the aquatic environment, it is not a psychrophilic organismand normally it is found in the intestinal tract of a wide variety of animals andin humans. So Salmonella can be shed through feces to the environment andthus could contaminate soil, pasture, streams, lakes, rivers and seas. Seafoodcan be contaminated from salmonella when captured in polluted and inshoreseawaters, or during handling from contaminated personnel. In a 9-year surveyby the US Food and Drug Administration (FDA) on the incidence of Salmo-nella in 11,312 samples of import and 768 samples of domestic seafood, theoverall incidence was found to be 7.2 and 1.3%, respectively (Heinitz et al.2000). Also, food wastes and animal manure may be fed to farmed fish andcrustaceans, and brackish waters may be used for aquacultures, potentiallycontaminating such products with salmonella (Reilly and Twiddy 1992; Jayet al. 1997).

V. parahaemolyticus is causing sporadic foodborne infections and out-breaks worldwide, with gastroenteritis being the most common clinical mani-festation. It is indigenous to the marine environment and its survival is affectedby temperature, not surviving in seawater below 10C (Desmarchelier 1997).Seawater temperatures in Greece are ideal for survival and growth of Vibrioparahaemolyticus and, in the study carried out by Davies et al. (2001), it wasfound in various fish from Greece (anchovy, bogue, mackerel, mussels,picarel, mullet), in relatively high incidence (14%), only second to that ofPortuguese fish (35%). In the present survey there were only two isolations ofV. parahaemolyticus, (2%) from marine fish (bogue). Also, in 1995, during thecholera epidemic in the neighboring countries, 92 seafood samples wereroutinely examined at the Food Microbiology Unit, Microbiology Department(Vibrio Reference Laboratory for Northwestern Greece), and one sample (1%)was found contaminated with V. parahaemolyticus (Papadopoulou et al.1996).

S. aureus is part of the normal human and animal microflora and maybe found in an aquatic environment polluted by sewage. Therefore S. aureusis an important pathogen, causing a wide range of diseases, including food-borne infections and intoxications. Staphylococcal food poisoning is one ofthe commonest types of foodborne disease worldwide usually associatedwith meat, poultry and dairy products. The commonest way food is con-taminated is through time and temperature abuse following improper han-dling. Because of its halophilic nature, S. aureus can survive in the marineenvironment and may contaminate seafood. In the present investigation, theincidence of S. aureus isolation ranged from 0% (squids and octapuses) to ashigh as 56.6% for mussels and 80% for marine fish. However, reports on S.aureus isolation from fish and seafood are limited. In a study in Argentina onindicator and foodborne pathogens on hake fillets for export, S. aureus wasnot isolated from any sample (Belchior and Pucci 2000), while in another


study in the U.S., S. aureus was isolated from whole catfish and catfishfillets (Ramos and Lyon 2000). Nevertheless, the presence of S. aureus inraw fish is of little public health importance, because it cannot propagate incompetition with fishes’ natural microflora, and, if fish products are involvedin food poisoning, then the origin of the bacteria is the handlers rather thanthe fish.

C. perfringens is one of the most widely spread pathogens in the envi-ronment and an important cause of food poisoning, often associated with largeoutbreaks (Pollock and Whitty 1991; Hook et al. 1996). It causes a variety ofsymptoms in humans such as gas gangrene, gastroenteritis, necrotic enteritisand diarrhea in mild cases. C. perfringens is a minor part of the normal fecalmicroflora of man and animals, and it is contaminating food mainly throughanimal feces, inappropriate handling and storage of prepared food and tem-perature abuse (Bates 1997). It grows at elevated temperatures (43–45C) andfresh or frozen seafood is a rather poor vehicle of C. perfringens food trans-mission. In our study, the incidence of C. perfringens was very low (1%), andthe isolate was detected in a sample of freshwater-farmed fish (trout). C.perfringens has been isolated from decomposing skipjack tuna. However,these reports do not concern fresh fish, but canned, vacuum packed, marinatedor abused fish, and this is suggestive of the potential risks for the public health,owing to the presence of any pathogenic type of Clostridium spp. in marine orfreshwater fish.

Yeasts of the species Candida are opportunistic pathogens, and the iso-lation of two strains, from marine (1%) and freshwater fish (1%), might beattributed to mishandling. Fungi are common contaminants of cereals, andsome species are involved in foodborne diseases through the production ofhighly toxic mycotoxins. However, the fungal species of Penicillium, Penicil-lium oxalicum (1%) and Penicillium italicum (1%), isolated from the fresh-water fish in this study are not toxigenic, and their presence coincides withcontamination as a result of mishandling. Reports on the incidence of anyyeasts or moulds in seafood are very scarce. In a study by Spanish researchers,the isolation of Candida albicans, Debaryomyces hansenii, Rodotorula rubra,Rodotorula glutinis and Saccharomyces cerevisiae from fish is reported(Vazquez-Juarez et al. 1994).

Marine and fresh water fish, either free living or cultured, were notconsidered to be important vectors of human pathogens. Then again, thissituation is changing, partly as a result of environmental pollution andincreasing animal densities as a consequence of a rapidly growing foodindustry and partly as a result of increasing awareness by health care pro-viders on seafood pathogens that may result in human illness. Nonetheless,the presence of pathogenic microorganisms represents a safety concern inseafood eaten raw and in cases wherein the pathogen has a very low


minimum infective dose, such as the case with e.g., Salmonella typhi, Shi-gella, E. coli O157 Campylobacter and Listeria. For most foodborne infec-tions and intoxications, it is not simply the presence of certain bacteriaspecies, but their growth to large numbers that represent a safety risk. In thepresent study, the levels of bacterial contamination were not counted for eachspecies, yet the presence of a wide range of pathogens (A. hydrophila, Y.enterocolitica, V. parahaemolyticus, S. aureus, C. albicans, C. perfringens),most of which are associated with foodborne diseases, indicates the potentialrisks for the safety of the so-called “healthy” seafood. Although most of theisolated genera are heatlabile and adequate cooking will inactivate them,improper handling and cross-contamination or raw seafood eating habits,might pose a health hazard, especially to susceptible populations such as theimmunosupressed, children and elderly people.

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microbiological and pathogenic contaminants of seafood in greece

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