Understanding Chemical Contamination of Food

Chemical contamination occurs when food is contaminated by chemicals
September 7, 2017

Chemical contamination occurs when food is contaminated by chemicals. Some of the most common causes of chemical contamination are cleaning products or pesticides and herbicides from unwashed fruit and vegetables.

The main types of chemical contaminants are:

  • industrial chemicals
  • agricultural chemicals
  • toxic metals
  • preservatives
  • naturally occurring toxins

Industrial chemicals

Industrial chemicals and cleaning products include detergents, sanitizers and other chemical products that you may have on site.

Always store these well away from food and food preparation areas, and store in their original labelled containers.

Never store chemicals in containers that were used for food, and don’t store food in containers that were used for chemicals. And always remember to rinse items when cleaning and sanitizing.

Agricultural chemicals

Agricultural chemicals include herbicides, pesticides and fertilizers that may be present on fruit and vegetables.

Always wash fruit and vegetables – even if the item has a thick skin or rind, you are still in danger of transferring chemicals from the outside to the inside when you cut into the product.

Choose fresh produce suppliers for your business that have programs in place to prevent contamination.

Toxic metals

Toxic metal contamination can occur when using pots and pans, food containers or utensils that have been manufactured using non-food grade materials, or that are not suitable for the purpose for which they are being used.

Storing acidic food in galvanized metal containers can cause chemical contamination. Use food grade plastic containers instead.


Preservatives are ingredients added to food to make it last longer or taste better. Example preservatives include sulphites in wine and nitrates used in meat.

Adding too much preservative to a food can be harmful to human health. Always use reputable suppliers and follow instructions when using these products.

Naturally occurring toxins

Naturally occurring chemical toxins are chemicals that are produced or contained naturally within shellfish, seafood or plants.

These toxins may not cause any harm to the organism that produces them but can be harmful to humans. Paralytic Shellfish Poisoning is an example of an illness caused by consuming a naturally occurring toxin.

Always purchase seafood and fresh produce from reputable suppliers to avoid this type of toxin.

Find out more about contamination

There are three types of contamination: chemical, biological and physical. Any of these types of contamination can occur in a food business, and rigorous controls are required to prevent it from happening.

Control methods and procedures should be laid out in detail in your Food Safety Plan. Food Safety Plans are important for any food business and help to protect consumers from food safety risks, including food poisoning or allergic reactions. In most provinces and territories, Food Safety Plans are required by law and should be based on the seven principles of HACCP.

Find out more about Food Safety Plans and the seven principles of HACCP by downloading the CIFS Guide to Understanding HACCP Principles.