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Can Botulism Grow in the Refrigerator? – The Answer!

You know that feeling you have when you’ve eaten food that might be off? Your stomach just isn’t happy and neither are you.

Fortunately, most food poisoning passes and isn’t more than just uncomfortable. Botulism, on the other hand, is something that really should be avoided.

Can botulism grow in the refrigerator?

The bacteria causing botulism need little or no oxygen, just enough water, low levels of sugar, acid, and salt, and a temperature of above 3 °C (37 °F). The average temperature in a fridge is above this temperature and the other conditions are not those favored by the botulism bacteria. This means that botulism is highly unlikely to grow in the refrigerator.

What is botulism?

You will know botulism as ‘food poisoning.’ Indeed, it does present with severe stomach cramps and nausea, but can also have more severe symptoms, which makes it quite a dangerous condition. This is why you should avoid it developing.

Botulism is caused by bacteria that can grow in some foods. The bacteria are protected by spores, which will release the bacteria under specific conditions.

How common is botulism?

Botulism is a very rare condition. Although the spores do occur in various places, they are mostly dormant. Because the spores themselves cannot affect anyone, it’s very rare that a person will contract botulism.

How does botulism develop?

The bacteria that cause botulism are transported by spores that get into food that has been preserved incorrectly.

The bacteria are basically ‘housed’ in spores, which protect them from the environment that may destroy them. They also mean that the bacteria can survive for a while before ever becoming active.

To develop into a problem, the bacteria need specific conditions to be released. They need just about no oxygen; low levels of sugar, acid, and salt; just enough water; and a certain range of temperatures. The optimum temperature for activating the bacteria that cause botulism is 3 °C (37 °F).

What food can be affected by botulism?

It’s important to remember the conditions in which botulism can grow. The starting point is somewhere that has little or no oxygen, which means food that is preserved in sealed cans or bottles.

Food that is processed commercially is extremely unlikely to develop botulism, but food that is canned or processed at home can develop botulism, if it’s not processed correctly.

How can I tell if my food has botulism?

If a can or jar you have bought from the store has a ‘blown’ lid (the lid is bulging outwards), then throw it away. It doesn’t necessarily contain botulism, but this is a sign that something is wrong and you shouldn’t take the risk that the toxins may be present.

If food has been left out of the fridge for a day, especially if it has been wrapped in something like foil, or even in a plastic box, then you should be cautious about it. The botulism spores can be activated in those conditions.

What foods develop botulism?

Fresh fruit

Botulism needs specific conditions to grow in, which begin with very low levels of oxygen.

Even in the refrigerator, fresh fruit is not usually kept in a sealed container, so it is usually open to quite a lot of oxygen. This means that botulism is not going to grow on fresh fruit in the refrigerator.

Canned food

There is little or no oxygen in canned or preserved food, which is one of the main criteria for the bacteria causing botulism to grow.

However, provided that the canning process has been done properly, then botulism is not a problem.

Anything is possible, though, and there are some instances when the bacteria can become active.

This can be indicated by evidence that the can is ‘blowing’: look for any sign of pressure being exerted outwards.

In a glass jar, the lid will actually pop. This can be a sign of danger and you should discard that can/bottle immediately.

It’s not necessary to keep tinned food in the refrigerator until it’s opened and you should use the contents within a few days after opening to avoid any risk whatsoever.

Raw meat

Raw meat that is sealed and kept in the fridge will not develop botulism. This means that you must make sure meat is always covered in the fridge.

Sliced meat that is left out of the fridge even for a few hours should not be consumed, as there is a slight chance that the spores that contain the bacteria can be activated.

Don’t buy sliced meat that has been laid out. If you buy processed meat, make sure it’s sealed. Keep it in the fridge and use it very soon after opening.

Cooked meat

Sliced, cooked meat that is left out of the fridge even for a few hours should not be consumed, as there is a slight chance that the spores that contain the bacteria can be activated.

Don’t buy sliced meat that has been laid out. If you buy processed meat, make sure it’s sealed. Keep it in the fridge and use it very soon after opening.

Desserts

Desserts usually contain quite a lot of sugar, so they should be safe from botulism. However, always check the can/bottle for any signs of ‘blowing’. If everything is fine, then the dessert can be eaten.

Even though botulism doesn’t usually grow in the fridge, make sure that you use an opened dessert within 24 hours after opening.

Make sure that it is put directly into the fridge and keep it there until you use it.

Frequently Asked Questions About Can Botulism Grow in the Refrigerator

Can all food develop botulism?

It’s possible that any preserved or canned food can develop botulism. However, there are specific conditions for the bacteria to become active. The bacteria need little or no oxygen, a temperature above 3 °C (37 °F), low levels of acid, sugar, and salt, and just the correct amount of water.

If I keep food in the fridge, is it safe from botulism?

Botulism is not likely to develop in the fridge, because the temperature is too low for the bacteria to become active. However, opened and resealed food can contain the bacteria and should be eaten fairly immediately after being opened.


Conclusion

The optimum temperature for the bacteria causing botulism to become active is higher than that of the refrigerator, so food kept in the fridge should not develop botulism.

However, don’t take risks with any processed or preserved foods that have been opened.

Author Bio

Daniel Iseli (Head Chef)

Hi, my name is Daniel and I am passionate about cooking. I have been cooking for the past 20 years and am happy to share my best recipes and cooking-related knowledge with you.