78
H. Toyofuku
• As appropriate, make recommendations on the validation of methodology (e.g.
such as identifying other international organisations that are working in this area);
• As appropriate, make recommendations on possible changes to the Proposed
Draft Standard for Live and [Raw] Molluscs and the section of the Code on
Live and [Raw] Bivalve Molluscs arising from the expert advice and other issues
arising from the deliberations of the pWG.
The FAO/IOC/WHO expert consultation utilized existing chemical, single exposure based risk assessment approach, which is similar to risk assessments of
pesticide residues, and they tried to establish a provisional acute reference dose
(ARfD). Table 7.1 shows the outcomes of risk assessments, regulatory levels
implemented in some countries in 2004, and established Codex maximum levels
of each toxin per kg of mollusc flesh.
With regards to azaspiracid (AZA), the expert consultation established a provisional ARfD of 0.4 g/kg body weight (bw), based on the Lowest Observed Adverse
Effect Level (LOAEL) of 23 g per person in humans and a bw of 60 kg, using a
tenfold safety factor because of the small number of people involved. Insufficient
data on the chronic effects of AZA prevented the establishment of a Tolerable Daily
Intake (TDI). As shown in Table 7.2, the consumption of 100, 250 or 380 g shellfish
meat by adults would result in a derived guidance level of 0.0096 mg/kg shellfish
meat (SM) and 0.0063 mg/kg SM respectively.
At the pWG in Canada in 2006, the expert consultation report was reviewed.
Given the data available, the existing history of regulatory programs and the level of
consumer protection provided by those programs, the pWG agreed that the action
level of 0.16 mg/kg implemented in 2001 in Europe, New Zealand and Norway
should be maintained (Codex 2006b).
According to the pWG report, the basis of the European action level was based
on a risk assessment carried out by the Food Safety Authority of Ireland, which
suggested a regulatory limit of 0.12 mg/kg following the first recorded outbreak
of food poisoning linked to AZAs in 1995. However, the sensitivity of the mouse
bioassay was insufficient to detect the toxin at this level. It was subsequently
determined that the mouse bioassay threshold for detecting AZA was 0.16 mg/kg.
Consequently, the regulatory limit for this toxin group was set at this level. Finally
the WG recommended that the Codex standard (section 1.5) should identify an
action level for AZA of 0.16 mg/kg (Codex 2006b).
During the discussion at the 28th session of the CCFFP, a Reevaluation of AZA
was requested from FAO/WHO because there was a large difference between the
guidance level for AZAs recommended by the Expert Consultation and the limit in
the Proposed Draft Standard (Codex 2006a).
With regards to the brevetoxin group, based on a reported incident in humans
with a 60-kg body weight who consumed an estimated 100–150 g shellfish at
120 g PbTx-3 equivalents/100 g, an exposure of 2–3 g PbTx-3 equivalents/kg bw
was estimated. However, uncertainty existed in the accuracy of this dose estimate
because of a possible underestimation of the toxin levels actually present in shellfish,
and because the metabolites were not reliably extracted by the method used for
H. Toyofuku
• As appropriate, make recommendations on the validation of methodology (e.g.
such as identifying other international organisations that are working in this area);
• As appropriate, make recommendations on possible changes to the Proposed
Draft Standard for Live and [Raw] Molluscs and the section of the Code on
Live and [Raw] Bivalve Molluscs arising from the expert advice and other issues
arising from the deliberations of the pWG.
The FAO/IOC/WHO expert consultation utilized existing chemical, single exposure based risk assessment approach, which is similar to risk assessments of
pesticide residues, and they tried to establish a provisional acute reference dose
(ARfD). Table 7.1 shows the outcomes of risk assessments, regulatory levels
implemented in some countries in 2004, and established Codex maximum levels
of each toxin per kg of mollusc flesh.
With regards to azaspiracid (AZA), the expert consultation established a provisional ARfD of 0.4 g/kg body weight (bw), based on the Lowest Observed Adverse
Effect Level (LOAEL) of 23 g per person in humans and a bw of 60 kg, using a
tenfold safety factor because of the small number of people involved. Insufficient
data on the chronic effects of AZA prevented the establishment of a Tolerable Daily
Intake (TDI). As shown in Table 7.2, the consumption of 100, 250 or 380 g shellfish
meat by adults would result in a derived guidance level of 0.0096 mg/kg shellfish
meat (SM) and 0.0063 mg/kg SM respectively.
At the pWG in Canada in 2006, the expert consultation report was reviewed.
Given the data available, the existing history of regulatory programs and the level of
consumer protection provided by those programs, the pWG agreed that the action
level of 0.16 mg/kg implemented in 2001 in Europe, New Zealand and Norway
should be maintained (Codex 2006b).
According to the pWG report, the basis of the European action level was based
on a risk assessment carried out by the Food Safety Authority of Ireland, which
suggested a regulatory limit of 0.12 mg/kg following the first recorded outbreak
of food poisoning linked to AZAs in 1995. However, the sensitivity of the mouse
bioassay was insufficient to detect the toxin at this level. It was subsequently
determined that the mouse bioassay threshold for detecting AZA was 0.16 mg/kg.
Consequently, the regulatory limit for this toxin group was set at this level. Finally
the WG recommended that the Codex standard (section 1.5) should identify an
action level for AZA of 0.16 mg/kg (Codex 2006b).
During the discussion at the 28th session of the CCFFP, a Reevaluation of AZA
was requested from FAO/WHO because there was a large difference between the
guidance level for AZAs recommended by the Expert Consultation and the limit in
the Proposed Draft Standard (Codex 2006a).
With regards to the brevetoxin group, based on a reported incident in humans
with a 60-kg body weight who consumed an estimated 100–150 g shellfish at
120 g PbTx-3 equivalents/100 g, an exposure of 2–3 g PbTx-3 equivalents/kg bw
was estimated. However, uncertainty existed in the accuracy of this dose estimate
because of a possible underestimation of the toxin levels actually present in shellfish,
and because the metabolites were not reliably extracted by the method used for