Home canning and bottling of seafood, such as fish and shellfish, like lobster, clams and whelks, is a popular activity for Canadians. Home canning and bottling allows people to enjoy their favourite seafood when it isn't in season or when it can't be harvested. This also allows Canadians to store seafood that would otherwise spoil quickly. However, if seafood isn't properly canned or bottled, it can cause botulism.
Botulism is a serious and sometimes fatal illness that can result from eating improperly prepared, canned or bottled food. Botulism is caused by bacteria called Clostridium botulinum (C. botulinum) that produce a toxin. The bacteria and its toxin are invisible to the naked eye and don't change the colour, odour or taste of food. Preventing the toxin from forming is essential as it's very poisonous and isn't necessarily destroyed by heating. C. botulinum is found naturally in soil and water. The bacteria can grow in a moist, oxygen-free environment, so, home canning and bottling of seafood provide the ideal conditions for the bacteria to multiply and produce the toxin, unless the food is properly prepared.
C. botulinum has a protective structure called a spore. Destroying the spore requires a higher temperature than boiling water. If the heating process isn't intense enough or if the food isn't acidic (i.e. pH 4.6 or less), the botulism bacteria can multiply and produce toxins.
All people are at risk for botulism. Symptoms of botulism range from nausea, vomiting, fatigue, dizziness, headache, double vision and dryness in the throat and nose, to respiratory failure, paralysis and, in some cases, death. The onset of symptoms is generally from 12 to 36 hours after ingesting the toxin. The duration of illness may be two hours to 14 days, although some symptoms may last longer. Every year in North America, people fall sick from botulism after eating home-canned food which was not properly prepared.
Preserving Seafood at Home
Seafood is a low-acid food. For low-acid foods, it isn't enough to heat the bottles or cans to boiling water temperatures, because the bacteria that causes botulism are very resistant to heat. To home-can or bottle any low-acid food such as seafood, a piece of specialized equipment called a pressure canner should be used. Pressure canners use steam under high pressure to ensure that the low-acid food reaches the high temperatures necessary to eliminate the bacteria that causes botulism. These high temperatures can only be reached with a pressure canner. Ensure the pressure canner is working properly and follow the manufacturer's instructions carefully.
Always wash your hands, utensils and equipment with warm, soapy water prior to the start of the canning or bottling process as well as during clean up afterwards.
Also, don't substitute the jar size or the amounts of ingredients that are called for in the recipe. Substitutions can affect the time the canned or bottled food requires in the pressure canner. Making substitutions and changing the jar size can cause the botulism bacteria to remain in the finished canned or bottled product. The product must be packed in a sealed leak proof/air tight container. Use the final product within one year for best quality. Once the container has been opened, refrigerate leftovers immediately and discard no more than 3-4 days after opening.
Buying Canned or Bottled Products
Products for sale that are prepared according to federal regulations (commercially prepared) are processed under strict controls which minimize or eliminate hazards such as foodborne illness.
Never eat canned food if the item appears to have been tampered with, if the seal has been broken, the lid is popped, or if the container is swollen or leaking. If in doubt, throw it out!
What is the Government of Canada Doing to Keep Our Food Supply Safe?
The Government of Canada is committed to providing safe food to all Canadians.
Health Canada establishes regulations and standards relating to the safety and nutritional quality of foods sold in Canada. Through inspection and enforcement activities, the Canadian Food Inspection Agency verifies that food sold in Canada meets Health Canada's requirements.
For more information
- Home Canning and Botulism
- In Your Kitchen: Safety Tips
- Recalls and advisories
- Report an Unsafe Product
- Be Food Safe
- Food Safety Facts on Botulism
- Food Safety Portal - Canadian Partnership for Consumer Food Safety Education
- Food Safety Tips
- Date modified: