Poisonous Mackerel etc.??

[Andy Macfarlane]

Has anyone ever heard of, or encountered, these two lovely poisons?

 

CIGUATERA FISH POISONING (CFP)

CFP can occur with subtropical and tropical marine finfish normally considered to be safe, such as snapper, sea bass, grouper, barracuda and mackerel. CFP can arise from the consumption of such fish that have accumulated naturally occurring toxins (ciguatoxin and maitotoxin) through their diet. The toxins are known to originate from several algae species.

 

Symptoms

CFP produces a combination of gastrointestinal, neurological, and cardiovascular symptoms within 6 hours of eating toxic fish as follows:

 

initially - diarrhoea, vomiting, and abdominal pain

subsequently - neurological problems including reversal of temperature sensation (i.e. hot feels cold), muscular aches, dizziness, anxiety, sweating, and a numbness and tingling of the mouth and fingers/toes.

muscular paralysis and death have been documented but are rare

Ciguatera poisoning is usually self-limiting, and although recovery times vary, signs of poisoning often subside within several days from onset. However, in severe cases the neurological symptoms are known to persist from weeks to months.

 

Precautions/Control

As the occurrence of toxic fish is sporadic, and not all fish of a given species or from a given locality will be toxic, to absolutely prevent intoxication no tropical reef fish should be eaten at all.

 

 

SCOMBROTOXIN POISONING

Scombrotoxin poisoning occurs after eating scombroid fish (e.g. tuna, mackerel, bonito, mahi mahi) and sometimes others (e.g. sardines) that have been stored or handled improperly. If such fish are not refrigerated below 4oC or processed immediately after being caught, spoilage bacteria (e.g. Morganella, Klebsiella, Hafnia and Proteus species) can grow rapidly. These bacteria break down (decarboxylate) the generally large quantities of histidine in the muscles of this group to produce sufficient quantities of histamine and possibly other associated compounds that, in combination, cause illness when eaten. Histamine is heat stable, so once bacterial growth has resulted in scombrotoxin formation, neither cooking, canning, or freezing reduces the toxic effect.

Distribution of the toxin within an individual fish fillet or between cans in a case lot can be uneven, with some sections of a product causing illnesses and others not. Common sensory examination (e.g. by sight or smell) by the consumer cannot ensure the absence or presence of the toxin. Chemical testing is the only reliable test for evaluation of a product.

 

UK Statistics

Between 1992 and 1999 over two thirds (68%) of outbreaks of infectious intestinal disease involving fish and shellfish were caused by scombrotoxins. There is a seasonal peak, with more cases occurring in the summer months due to the greater potential for temperature abuse of the fish.

In the UK there are about 40 – 50 incidents each year, affecting about 100 people. These can be categorised as follows:

 

sporadic cases – 60%

general outbreaks – 26%

family outbreaks – 14%

Tuna (fresh, frozen or canned) and mackerel are the most commonly implicated foods. Incidents involving fresh, vacuum-packed imported tuna steaks have increased in recent years, accounting for more than half of confirmed incidents in 1996.

 

Symptoms

Initial symptoms may occur within minutes and for up to 3 hours after ingestion of toxic food, with most cases occurring within 1 hour. Symptoms may include:

 

a tingling or burning sensation in the mouth

a flushing of the face and neck

a feeling of intense heat and general discomfort

a drop in blood pressure

headaches

itching of the skin

The symptoms may progress to nausea, vomiting, and diarrhoea and may require hospitalisation, particularly in the case of elderly or patients who are weakened.

 

Precautions/Control

Prevention of the following identified causal factors:

 

delays in landing caught fish

poor temperature control

unhygienic food handling practices

In addition, official sampling of foodstuffs acts as a means to identify and prevent potentially hazardous foods reaching consumers. The legally acceptable level is 10 mg of histamine per 100 g of fish.

[Zigs]

very interesting andy, trouble is, snatcher chesters 1 & i have those symptoms most of the time

 

i have long been aware that mackerell fat breaks down into hystamine within the hour on a hot beach. if i havnt taken freezer packs with me, i keep a tupperware tub with packs of salt in it, in the back of the van so i can salt the fillets down immediatly.

[Norm B]

Originally posted by Andy Macfarlane:

[QB] Has anyone ever heard of, or encountered, these two lovely poisons?

 

CIGUATERA FISH POISONING (CFP)

CFP can occur with subtropical and tropical marine finfish normally considered to be safe, such as snapper, sea bass, grouper, barracuda and mackerel. CFP can arise from the consumption of such fish that have accumulated naturally occurring toxins (ciguatoxin and maitotoxin) through their diet. The toxins are known to originate from several algae species.

 

:cool: In the Carribbean locals throw the fish livers to dogs, if the dogs show no signs of ill effects a couple of hour later, the fish are considered 'fit to eat'.

[***Simon***]

just eat it and if u die u die and if u dont u dont

[Zigs]

u die if you don't eat, thats a fact

[Happy Dude]

i remember reading about captain cooks voyages around australia and they kept cats on board.

 

when they got a fish they suspected of ciguatera they fed some of it to a cat, if it pegged out they didn't eat it.

 

they must have known by experience which fish species were prone to it eg barracuda, trevally and other reef predators.

 

it seems to be localised though, if you caught a 40lb cuda in florida or the barrier reef you shouldn't eat it, whereas off the kenya coast you can eat it no problems

[Vagabond]

Ciguatera toxicity can be quite localised - in Queensland the "Red Bass" Lutjanus bohar is considered high risk (and sale is forbidden)

 

The other side of Australia (WA ) it is considered safe. OK that is a long distance to call "local" but it illustrates the point.

 

"Ciggy" is something that occurs in top predators ie at the top of the food chain. The bigger a pred is, the more likely it is to carry ciggy.

 

If you lack dogs or cats to try your suspect on - rub some of the fish along your lower lip. If you feel a tingling sensation after a few minutes, then the fish is certainly NOT safe to eat.

 

Disclaimer; - If you DON'T feel that sensation, whether to eat the fish or not is YOUR decision demon .

 

[ 24. July 2005, 05:46 PM: Message edited by: Vagabond ]

[skippytheroo]

Are there many cases of this in the UK each year?

[Norm B]

Originally posted by Vagabond:

[QB] Ciguatera toxicity can be quite localised - in Queensland the "Red Bass" Lutjanus bohar is considered high risk (and sale is forbidden)

 

The other side of Australia (WA ) it is considered safe. OK that is a long distance to call "local" but it illustrates the point.

 

"Ciggy" is something that occurs in top predators ie at the top of the food chain. The bigger a pred is, the more likely it is to carry ciggy.

 

:cool: I understand it's to do with the diet of the predator. If a barracuda is feeding on parrot fish then it's likely to be toxic because the parrot fish eats coral which is toxic but harmless to the parrot fish, a 'cuda feeding on parrot fish will in its self become toxic, a bit like tuna absorbing mercury from its food, it doesn't harm the tuna but the tuna will be toxic to us over a period of time. I've gone off exotic fish all of a sudden.

[Norm B]

Originally posted by Norm B:

[QB]

Originally posted by Vagabond:

[QB] Ciguatera toxicity can be quite localised - in Queensland the "Red Bass" Lutjanus bohar is considered high risk (and sale is forbidden)

 

The other side of Australia (WA ) it is considered safe. OK that is a long distance to call "local" but it illustrates the point.

 

"Ciggy" is something that occurs in top predators ie at the top of the food chain. The bigger a pred is, the more likely it is to carry ciggy.

 

:cool: I understand it's to do with the diet of the predator. If a barracuda is feeding on parrot fish then it's likely to be toxic because the parrot fish eats coral which is toxic but harmless to the parrot fish, a 'cuda feeding on parrot fish will in its self become toxic, a bit like tuna absorbing mercury from its food, it doesn't harm the tuna but the tuna will be toxic to us over a period of time. There was advice at one time not to eat eels and flounders caught in the Mersey because of their diet and living in the mud they became full of heavy metals like mercury and cadnium, but whiting etc were OK.

I've gone off fish all of a sudden.