The New Straits Times, August 28,1995
Q: Do the canned goods we buy ever cause the food poisoning known as botulism?
A: This kind of food poisoning is relatively rarely caused by commercially prepared food. It normally occurs from eating food that is improperly canned or preserved at home. They are usually raw or insufficiently cooked, stored for a certain period and ingested without heating.
The poison that causes botulism is made by a bacteria known as Clostridium botulinum. It may be caused by the bacteria toxins that are ingested preformed or are elaborated in the intestine by bacteria contaminating the particular food. The bacteria likes to grow in the absence of oxygen, so if food is not heated enough to kill the bacterial spores, it will continue to grow freely once the food is canned.
When selecting a canned food, do not choose a deformed, dented or a swelled can. When clostridium grows inside a can, it can produce enough gas to make the can sell and give off gas when it is opened. However, not all contaminated canned foods exhibit these signs.
If your are in doubt of a canned food products, heating the food to a temperature of 80°C for 30 minutes or 100°C for 10 minutes should make the food safe from the botulinum toxin. But other heat-resistant toxins that could be found in the food may not be eliminated by cooking.
If the pH of the food is lower than 4.5 (i.e. the food is acidic), toxin formation is unlikely, although there have been some reports of toxin production from pickled fish, especially herring kept at pH of 4.0 to 4.2.
Incases of poisoning, immediate attention must be given to ensure adequate airway and respiratory function. Poisoning by this heat-labile neurotoxin is manifested by severe muscle weakness and death is normally due to respiratory failure.
