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water. Viruses and bacteria are too small for the shellfish’s gills to detect or reject,
but due to their small size in relation to such food items as algae and small particles
suspended in the water, they tend to attach to these surfaces. Other pollutants of
public health concern that shellfish concentrate basically via this mechanism are
many types of pesticides, toxic algae, and ions of heavy metals attached to particulate matter (Croonenberghs 2000). Bivalves are minimally processed, and traditionally consumed raw or lightly cooked as a whole. The hazards of contamination of
bivalve by harmful microorganisms arise from the lack of traditional cooking procedures sufficient to ensure consumer safety. These conditions make them an important carrier of foodborne diseases (Oliveira et al. 2011).
5.2 Microbial Risks
Microbial hazards take the first place among food-borne risks. Microbial risks are
the most difficult to control hazards. The most common of food-borne diseases are
of bacterial origin, progressing faster and occur relatively quickly. Microorganisms
contaminated with food at any stage of production can pose a risk when it comes to
process errors, such as inadequate temperature applications. After bacterial contamination occurring in food for any reason reaches a certain level, it may cause
infection or intoxication when food is consumed (Tayar 2010).
Microbial contaminants are pathogenic microorganisms that cause disease in
shellfish-consuming humans. Included are faecal-borne viral, bacterial, and protozoan pathogens, and naturally occurring bacterial pathogens. The indicator bacteria
used within the shellfish industry are generally faecal (and total) coliforms and
Escherichia coli. Enterococci, Clostridium perfringens and other indicators are also
useful in helping to elucidate the sources of faecal-borne contamination in shellfish
waters. Faecal-borne bacteria are present in nearly all coastal waters where human
activities and animals contribute faecal contamination. Faecal-borne bacterial species have been the cause of significant outbreaks of shellfish-borne diseases (Jones
2009). Bivalves living in polluted waters are often subject to contamination from
domestic sewage and land run-off, which typically contain pathogenic bacteria such
as Salmonella spp. and Vibrio spp. (Gosling 2015). Faecal-borne bacterial pathogens account for a significant fraction of shellfish-borne disease in some areas. The
major microbial contaminants include viruses, vibrios, and to a lesser extent faecal
borne bacterium.
5.2.1 Bacterial Pathogens
Bacteria are everywhere in the marine environment. Shellfish can be a source of
bacteria for human pathogens. Raw and partially cooked mollusc shellfish have long
been vectors of infectious agents (Hariharan and Amadi 2016).
5 Shellfish Safety
water. Viruses and bacteria are too small for the shellfish’s gills to detect or reject,
but due to their small size in relation to such food items as algae and small particles
suspended in the water, they tend to attach to these surfaces. Other pollutants of
public health concern that shellfish concentrate basically via this mechanism are
many types of pesticides, toxic algae, and ions of heavy metals attached to particulate matter (Croonenberghs 2000). Bivalves are minimally processed, and traditionally consumed raw or lightly cooked as a whole. The hazards of contamination of
bivalve by harmful microorganisms arise from the lack of traditional cooking procedures sufficient to ensure consumer safety. These conditions make them an important carrier of foodborne diseases (Oliveira et al. 2011).
5.2 Microbial Risks
Microbial hazards take the first place among food-borne risks. Microbial risks are
the most difficult to control hazards. The most common of food-borne diseases are
of bacterial origin, progressing faster and occur relatively quickly. Microorganisms
contaminated with food at any stage of production can pose a risk when it comes to
process errors, such as inadequate temperature applications. After bacterial contamination occurring in food for any reason reaches a certain level, it may cause
infection or intoxication when food is consumed (Tayar 2010).
Microbial contaminants are pathogenic microorganisms that cause disease in
shellfish-consuming humans. Included are faecal-borne viral, bacterial, and protozoan pathogens, and naturally occurring bacterial pathogens. The indicator bacteria
used within the shellfish industry are generally faecal (and total) coliforms and
Escherichia coli. Enterococci, Clostridium perfringens and other indicators are also
useful in helping to elucidate the sources of faecal-borne contamination in shellfish
waters. Faecal-borne bacteria are present in nearly all coastal waters where human
activities and animals contribute faecal contamination. Faecal-borne bacterial species have been the cause of significant outbreaks of shellfish-borne diseases (Jones
2009). Bivalves living in polluted waters are often subject to contamination from
domestic sewage and land run-off, which typically contain pathogenic bacteria such
as Salmonella spp. and Vibrio spp. (Gosling 2015). Faecal-borne bacterial pathogens account for a significant fraction of shellfish-borne disease in some areas. The
major microbial contaminants include viruses, vibrios, and to a lesser extent faecal
borne bacterium.
5.2.1 Bacterial Pathogens
Bacteria are everywhere in the marine environment. Shellfish can be a source of
bacteria for human pathogens. Raw and partially cooked mollusc shellfish have long
been vectors of infectious agents (Hariharan and Amadi 2016).
5 Shellfish Safety