Home- canning and Botulism

Canning our own fruits, vegetables and meat has many benefits but it can lead to serious food borne illness named Botulism. It is a rare but serious illness caused by a toxin that attacks the body’s nerves and causes difficulty breathing, medical paralysis and even death. The toxin is made most often by Clostridium botulinum bacteria in improperly home- canned, preserved or fermented foods which provide the right anaerobic condition (absence of oxygen) for the bacteria to make the toxin. Commercially canned foods are much less likely to be a source of botulism because modern canning processes kill C. botulinum spores.

Types of botulism

There are 3 main types of botulism

1. Infant botulism

It is the most common form and affects children younger than 12 months. It causes intestinal infection by the botulinum spores which affects the nervous system. These spores are more common in many foods, honey, milk and some juices. So it is important not to give honey to babies below 1 year old and make sure the milk and other food products are well pasteurized or cooked.

2. Food borne botulism

It can affect anyone who eats improperly home canned foods or any other foods which are a source of the botulinum bacteria

3. Wound botulism

It is rare and occurs when botulism toxin infects an existing wound.

Sources for food borne botulism

Low acid foods are the most common sources of botulism linked to home canning. These foods have a pH level greater than 4.6. Low acid foods include most vegetables like asparagus, green beans, beats, corn and potatoes, some fruits including tomatoes and figs, milk, all meats, fish and other seafood. However the disease has also occurred from spicy peppers, foil wrapped potatoes and oil infused garlic.

How to avoid botulism

The only way is to avoid eating contaminated food which can be achieved by following proper refrigeration, throwing out expired products, using correct methods for home canning foods.

Tips for home canning

• Use a pressure canner or cooker to thoroughly cook your food. Pressure cooker must be used to can vegetables at home because it can reach temperatures above boiling, which is necessary to kill botulism spores.
• Refrigerate any canned or pickled foods after you open them
• Refrigerate homemade oils infused with garlic or herbs and throw away any unused oils after 4 days
• Keep potatoes baked in foil hot until they are served or refrigerate them with the foil loosened so they get air
• To kill botulinum spores, the internal temperature of food should reach above 85⁰C for 10 mins.
• Consider boiling homemade canned foods for 10 minutes before you eat it. It is important to ensure the food is free of toxin- free
• Commercial cans or home canned products with dents or bulging lids should not be opened. Throw it away or return it unopened to the store where you bought it
• Never taste any food that smells foul, slightly off or doesn’t smell the way it normally should.

Signs for Botulism

Signs/symptoms can show up as quickly as 6 hours or as late as 10 days

The main signs of food borne botulism include

• Difficulty swallowing or speaking
• Dry mouth
• Facial weakness
• Blurred or double vision
• Drooping eyelids
• Difficulty breathing
• Nausea, Vomiting, Abdominal cramps
• Paralysis

In infants, botulism signs include

• Poor feeding
• Constipation
• Excessive sleepiness
• Poor reflexes

Although botulism can cause severe and prolonged symptoms, most people recover completely from the illness. Early treatment reduces permanent disability and death.