Dar seafood ppp standard

Table 8: Relative risk ranking estimates for cephalopod molluscs

Commodity	Hazard	Severity	Likelihood of adverse health effects	Relative risk Ranking
Cooked	A. hydrophila	Serious	Unlikely	Low
	V. parahaemolyticus	Moderate	Unlikely	Low
	V. vulnificus^1	Serious	Unlikely	Low
	Non-toxigenic V. cholerae O1	Moderate	Unlikely	Low
	E. coli (non-EHEC)	Moderate	Unlikely	Low
	Staphylococcus aureus	Moderate	Unlikely	Low
	Salmonella (non-typhoid)	Serious	Unlikely	Low
	Campylobacter spp.	Serious	Unlikely	Low
	Shigella spp.	Serious	Unlikely	Low
	Yersinia spp.	Serious	Unlikely	Low
	L. monocytogenes^1	Serious	Unlikely	Low
	Noroviruses	Moderate	Unlikely	Low
	Hepatitis A virus^1	Serious	Unlikely	Low
	Mercury^1	Serious	Unlikely	Low

1. For susceptible sub-populations the relative risk rankings are medium (severe x unlikely).
Key: EHEC = enterohaemorrhagic Escherichia coli.

Food safety risks due to crustacea

The hazards potentially associated with crustacea through the production and processing supply chain (Appendix 1) may be grouped as follows:

• 
  Endogenous bacteria that are human pathogens (A. hydrophila, L. monocytogenes, V. parahaemolyticus, V. vulnificus, V. cholerae O1/O139, non-O1/non-O139 V. cholerae).
  

• 
  Pathogens introduced through pollution or post-harvest contamination (E. coli, S. aureus, Salmonella spp., Campylobacter spp., Shigella spp., Yersinia spp., V. cholerae O1, hepatitis A virus, Noroviruses).
  

• 
  Environmental chemical contaminants/toxicants (mercury, arsenic).
  
  
  

The environment from which crustacea are harvested influences the range of hazards. Wild-caught crustacea from clean waters are unlikely to contain pathogens of enteric origin, while farmed/estuarine crustacea may be exposed to contamination in the growing environment.
The severity of illness caused by these hazards (Table 3) ranges from moderate (for example, V. parahaemolyticus, noroviruses), through serious (for example, L. monocytogenes, hepatitis A virus) to severe (for example, V. cholerae O1/O139). Some of the hazards are considered severe only for certain susceptible populations (for example, L. monocytogenes, hepatitis A virus). However, the relative risk ranking estimates below are determined for the general population, unless otherwise specified.

Prawns – green

Consumption data indicate that prawns are a food group occasionally eaten by a significant proportion of the population (Appendix 3; [7,9]). On this basis, evidence of the potential for a hazard to be present at an infectious or toxigenic level in this commodity is taken as the main determinant of the likelihood of adverse health effects. Adverse health effects due to each of the hazards identified in Appendix 1 is considered unlikely, as discussed briefly below.

Likelihood of adverse health effects: Unlikely

A. hydrophila: A. hydrophila has been implicated in food-borne illness due to prawn consumption in the United Kingdom [29], but there are no epidemiological or concentration data suggesting a significant likelihood of adverse health effects from pathogenic strains in Australia. The usual practice of cooking green prawns just before eating should significantly reduce the bacterial load.
E. coli, S. aureus, Salmonella, Campylobacter, Shigella and Yersinia species: Pathogenic strains of these bacteria may be present in prawns due to pollution of growing waters or post-harvest contamination. Results from testing of imported foods (Appendix 1) demonstrate there is some limited potential for contamination of imported prawns by these hazards. The usual practice of cooking green prawns just before eating should significantly reduce the bacterial load, but will not affect the concentration of staphylococcal enterotoxin, which is thermostable. However, significant time–temperature abuse is usually needed to allow proliferation of S. aureus to levels likely to produce sufficient enterotoxin to cause illness [46]. Furthermore, the organism is a poor competitor, and commensal bacteria would hinder its ability to grow and produce toxin.
Vibrio cholerae O1/O139: Toxigenic strains of V. cholerae O1 have been found in fresh water reaches of rivers in Australia but not in estuarine or marine environments [31].

There are only limited epidemiological [31] and concentration data suggesting a significant likelihood of adverse health effects from toxigenic V. cholerae O1 in Australia through consumption of prawns. Results from testing imported foods (Appendix 1) show no failures due to V. cholera O1/O139 in any seafood commodities. The practice of cooking green prawns just before eating should significantly reduce bacterial levels.

Vibrios (excluding toxigenic V. cholerae O1): V. parahaemolyticus, V. vulnificus and non-O1/O139 V. cholerae are found in estuarine and marine environments in Australia. There are limited data suggesting a significant likelihood of adverse health effects from vibrios through consumption of prawns. V. parahaemolyticus has been isolated from prawns [31] and non-O1/non-O139 V. cholerae has been found in imported crustacea. The usual practice of cooking green prawns just before eating should significantly reduce the bacterial load.
L. monocytogenes: There are limited data indicating the potential for food-borne listeriosis due to consumption of prawns. One small outbreak of Listeria bacteraemia has been reported, due to shrimp consumption, in the United States [63]. There are only limited data demonstrating the potential for L. monocytogenes to be present in uncooked prawns in Australia. Imported crustacea are not tested for L. monocytogenes under the Imported Foods Inspection Program, and there were no recalls coordinated by FSANZ in the period 1990–2003 for L. monocytogenes in crustacea. The practice of cooking green prawns just before eating should significantly reduce levels of this pathogen.
Enteric viruses: There are limited data indicating the potential for adverse health effects caused by exposure to enteric viruses due to consumption of prawns. There has been one outbreak of hepatitis A due to prawn consumption in Australia since 1995 (Appendix 2). Light cooking does not inactivate noroviruses [38,39], and hepatitis A virus has significant heat stability [40], so cooking may not inactivate these hazards.
Inorganic arsenic and mercury: ANZFA reviewed the public health risks due to heavy metal contamination in foods (including crustacea) in 1999 [5,7]. Data on concentrations of heavy metals in foods were used to provide an estimate of total dietary exposure. The results were as follows:

• 
  For inorganic arsenic, ANZFA determined that prawns contributed up to 52 per cent of the total dietary exposure, and high consumers of crustacea could receive up to 18 per cent of the PTDI for inorganic arsenic, assuming the inorganic arsenic content of seafood is 6 per cent of the total arsenic content.
  

• 
  For mercury, ANZFA concluded that crustacea contribute only 0.34 per cent to total dietary exposure of mercury [7].