Food poisoning associated with biotoxins in fish and shellfish

In recent times the number of blooms of algae that produce toxins has increased in frequency, intensity and geographical distribution. This review describes some of the illnesses caused by fish and shellfish contaminated with toxins produced by marine algae and by bacteria.

The increase in toxic algal blooms may be a result of increased awareness, aquaculture, eutrophication, or transport of cysts in ship ballast. Improved chemical methods for the detection of algal toxins are now being developed, and so the number of toxins recognized is increasing. Toxicological data on some of these algal toxins are lacking. Despite the increase in occurrence of algal toxins, scombrotoxic poisoning remains the most common cause of food poisoning associated with the consumption of fish and shellfish. This may be real or it may be a reflection of lack of suitable tests for algal toxins or under-recognition by workers in health care.

The major problem worldwide in this field is the lack of pure toxins for use in developing and standardizing chemical methods for toxin detection. Such methods would permit increased testing of both food and clinical specimens, and hence would prevent the entry of toxic food into the food chain and increase laboratory confirmation of incidents of illness.