Frequently Asked Questions

Get answers to your questions with the Australian Institute of Food Safety's Frequently Asked Questions section

What are the different types of food contamination?

There are three different types of food contamination - chemical, physical and biological.

All foods are at risk of becoming contaminated, which increases the chance of the food making someone sick. It’s important to know how food can become contaminated, so that you can protect against it.

Chemical contamination refers to food that has been contaminated by some type of chemical substance. Because chemicals can be very useful when cleaning in the kitchen, they can easily contaminate food. Chemicals must be properly labelled, and stored separately to food stuff to minimise the risk of contamination.

There are also chemicals that occur naturally in foods, like toxins in some fish, and in some cases minimal chemical contamination might not actually lead to illness. However, the food handler must always be aware of the presence of chemicals in food and take all reasonable precautions to make sure that chemical contamination doesn’t happen.

Biological contamination refers to food that’s contaminated by substances produced by living creatures – such as humans, rodents, pests or microorganisms. This includes bacterial contamination, viral contamination or parasite contamination that’s transferred through saliva, pest droppings, blood or faecal matter. Bacterial contamination is thought to be the most common cause of food poisoning worldwide, and the best way to protect against it occurring is by maintaining best food safety practices.

Physical contamination refers to food that has been contaminated by a foreign object at some stage of the production process. These objects have the ability to injure someone and can also potentially carry harmful biological contaminants, which then cause illness. An additional consequence of physical contamination is the upset caused to the person who finds the object. Things like band-aids, fingernails and pieces of cooking equipment are the last thing you would like to find in your meal.