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Paralytic shellfish toxins

In the body: These toxins block nerve signals: tingling and numbness, and in severe cases paralysis of the breathing muscles.

Not rated by dose: a flag on 3 reviewed foods, among them Pacific oysters, raw, Clams, cooked and Mussels, cooked. The list below has a line for each of 4 preparations.

Too much in one go. Harm from one big portion. A food measured against the agency’s dose shows the grams that reach it in one sitting.

All hazards

The limit

  • The agency’s figure0.5 µg STX equivalents/kg body weight
  • Basisacute reference dose (ARfD): the most in one sitting
    acute reference dose (ARfD) (EFSA CONTAM 2009): lowest-observed-adverse-effect level (LOAEL) about 1.5 µg STX eq/kg body weight from more than 500 human intoxications, factor 3 (lowest-observed-adverse-effect level (LOAEL) (human outbreak data))
  • Applies toper sitting; EFSA's large portion is 400 g of shellfish meat
  • Source EFSA 2009

Reviewed foods that carry it

3 reviewed foods carry it; none is rated by dose. A food counts once, as in the foods list: preparations sharing a page (raw and cooked, canned) count once; one with its own page counts apart. Below, one line for each of 4 preparations.

Grams to the limit

No reviewed food here has a measured level yet, so none has a gram figure. The limit is shown, ready for the first measurement; each line below says what the food is flagged for.

  1. Clams, cooked

    Not rated yet for a 100 g serving

    No gram figure for this food
    We have no measurement of this in this food, so there is no gram figure.

    EFSA 2009 · grade A

    How it’s rated

    Not rated: EFSA's 2009 acute reference dose for paralytic shellfish toxins is 0.5 µg saxitoxin equivalents/kg body weight, 35 µg for 70 kg in one sitting. No measured retail occurrence was found, and no figure is computed at a legal limit, so there is no grams figure. Harvest-area closures are the control, and cooking does not destroy the toxins.

    Intake: a large shellfish portion (EFSA: 400 g)

    Measured on: no measured retail occurrence found; harvest-area closure is the control (CFIA/CSSP action level 80 µg PSP toxins per 100 g meat, from a CFIA-authored search result, not opened)

  2. Eastern oysters, raw

    Not rated yet for a 125 g serving

    No gram figure for this food
    We have no measurement of this in this food, so there is no gram figure.

    EFSA 2009 · grade A

    How it’s rated

    Not rated: EFSA's 2009 acute reference dose (ARfD) for paralytic shellfish toxins is 0.5 µg STX equivalents/kg body weight, 30 µg for a 60 kg adult (35 µg at 70 kg) per sitting. No measured retail occurrence was found, so there is no grams figure, and none is computed at a legal limit. EFSA's own illustration: a 400 g portion at the EU limit of 800 µg/kg would give 320 µg, far over the ARfD. In Canada, control works by harvest-area closure.

    Intake: a large shellfish portion

    Measured on: no measured retail occurrence found; shellfish toxin control in Canada works by harvest-area closure

  3. Mussels, cooked

    Not rated yet for a 100 g serving

    No gram figure for this food
    We have no measurement of this in this food, so there is no gram figure.

    EFSA 2009 · grade A

    How it’s rated

    Not rated: EFSA's 2009 acute reference dose for paralytic shellfish toxins is 0.5 µg STX equivalents/kg body weight (35 µg at 70 kg) per sitting, but no measured retail occurrence was found, so no grams figure is computed at a legal limit. Canada controls it by harvest-area closure (action level 80 µg per 100 g of meat), and cooking does not destroy the toxins.

    Intake: a large shellfish portion (EFSA: 400 g)

    Measured on: no measured retail occurrence found; shellfish toxin control in Canada works by harvest-area closure (CFIA/CSSP action level 80 µg PSP toxins per 100 g meat, from a CFIA-authored search result, not opened)

  4. Pacific oysters, raw

    Not rated yet for a 125 g serving

    No gram figure for this food
    We have no measurement of this in this food, so there is no gram figure.

    EFSA 2009 · grade A

    How it’s rated

    Not rated: EFSA's 2009 acute reference dose (ARfD) for paralytic shellfish toxins is 0.5 µg STX equivalents/kg body weight, 30 µg for a 60 kg adult (35 µg at 70 kg) per sitting. No measured retail occurrence was found, so there is no grams figure, and none is computed at a legal limit. EFSA's own illustration: a 400 g portion at the EU limit of 800 µg/kg would give 320 µg, far over the ARfD. In Canada, control works by harvest-area closure.

    Intake: a large shellfish portion

    Measured on: no measured retail occurrence found; shellfish toxin control in Canada works by harvest-area closure

Sources