Dar seafood ppp standard

Table 4.23: Mercury concentrations in predatory fish in Australia

	Mean mercury levels (mg/kg) – number of samples in parentheses
	NSW Health Commission 1978	Working Group on Mercury in Fish 1979	WA Food Monitoring Program 1993	White 1999
Gemfish	–	0.68 (148)	–	–
Tuna, Skipjack	–	0.15 (20)	–	–
Tuna, Southern Bluefin	–	0.22 (219)	–	–
Tuna, Yellow Fin	–	0.38 (20)	–	–
Swordfish	1.98	–	–	0.98 (8)
Marlin, Black	–	7.27 (42)	–	0.57 (3)
Shark	–	–	–	–
Angel	–	0.36 (36)	–	–
Blacktip Whaler	–	1.48 (8)	0.41 (14)	–
Blue Pointer	–	1.93 (2)	0.83 (2)	–
Blue Whaler	–	0.41 (2)	–	–
Bronze Whaler	–	0.72 (159)	0.52 (33)	–
Carpet	–	1.02 (76)	0.69 (12)	–
Gummy	–	0.44 (507)	0.29 (4)	–
‘Shark’	–	–	–	0.48 (26)

Source: Extracted from M&S Food Consultants 2001.

Ranking of hazard: Mercury, in the form of methylmercury, represents a severe hazard for the developing foetus, which may exhibit adverse effects of long duration at a much lower level of exposure than in the general population. For the general population, mercury is ranked as a serious hazard (Section 3, Table 3). The effects can be debilitating, with the possibility of on going chronic sequelae.

Zinc

Zinc is an essential element that is found in a wide variety of foods at relatively low levels. Diet is the main source of zinc for consumers. Additional sources of exposure may occur from drinking water stored in old galvanised containers and dietary supplements may also add to the daily zinc burden.

Regulation of zinc in seafood: There is no maximum limit for zinc in seafood specified in the Code. However, following a review, generally expected levels were established for specific seafood commodities in order to identify the minimum level of contamination that is reasonably achievable, and to provide a trigger for remedial action if a level is exceeded (Table 4.24).

Table 4.24: Guideline generally expected levels for zinc in seafood

Commodity	GELs median (mg/kg)	GELs 90th percentile (mg/kg)
Crustacea	25	40
Fish	5	15
Oysters	130	290

GELs = generally expected levels

Hazard identification and characterisation: Limited human toxicological data are available for determining the maximum tolerable intake for zinc. Vomiting and fever after acute exposures, and damage to kidneys and pancreas after sub-chronic and chronic exposures in animals have been observed at dietary levels above 1000 mg/day. Copper and iron deficiencies have been documented in animals and in humans exposed to chronically high intake of zinc.
Interaction with other nutrients especially copper, where its absorption and utilisation is influenced at a biochemical level has been observed at intakes as low as 60 mg/day, when zinc was taken as a supplement to the diet. Biochemical changes observed at 60 mg/day were interpreted as the first indicator that the copper-dependent processes were affected.
JECFA established a PTDI of 1 mg/kg bw in 1982. To ensure that very few individuals in a population have an intake of 60 mg/day or higher, a WHO/FAO/IAEA Expert Consultation (1996) recommended that the adult population mean intake should not exceed 45 mg/day, assuming a 20 per cent variation in intake. The PTDI for zinc, for the purposes of a previous risk assessment by FSANZ was set at 1 mg/kg bw, based on a 60 kg adult.
Recent surveys on zinc in seafood: Smoked fish fillets, oysters, canned red salmon and seafood sticks were examined for zinc in the 1994 Australian Market Basket Survey. Concentrations of zinc ranged from 3.7 mg/kg to 12 mg/kg for smoked fish fillets; 6.4 mg/kg to 14 mg/kg for canned red salmon; 1.7 mg/kg to 2.6 mg/kg for seafood sticks; and 120 mg/kg to 660 mg/kg for oysters (Marro 1996).
Canned crab, fish fillets, mussels and canned red salmon were analysed for zinc in the 19th Australian Total Diet Survey (FSANZ 2001). Levels detected (minimum, maximum, median; units mg/kg) were: canned crab (22.0, 49.0, 25.0); fish fillets (3.6, 11.0, 6.3); mussels (13.0, 63.0, 26.0); and canned red salmon (5.7, 9.9, 8.1).
Prawns, fish fillets and portions, and canned tuna were analysed for zinc in the 20th Australian Total Diet Survey (FSANZ 2003). Levels detected (minimum, maximum, median; units mg/kg) were: prawns (7.8, 17.0, 12.0); fish fillets (2.9, 5.4, 3.7); fish portions (3.4, 11.0, 5.0); and canned tuna (6.6, 12.0, 8.7).
Dietary exposure to zinc: The mean total dietary exposure to zinc for all respondents ranged from 19–20 per cent PTDI. The dietary exposure estimates for high consumers of single food commodity groups indicated that consumers of oysters might receive relatively high levels of zinc from this source compared to any other food. Oysters are considered a food that is ‘occasionally consumed’ and the median consumption level was taken to be a representative level of consumption for a high consumer. Total dietary exposure to zinc for high consumers of oysters, assuming mean exposure from all other foods, is estimated to be 38 per cent of the PTDI (ANZFA 1999b).

Ranking of hazard: Zinc is ranked as ‘moderate’ in terms of adverse health effects (Section 3, Table 3). Acute exposure to high levels has an emetic effect of short duration.