High-risk foods, also called potentially hazardous foods, are foods that have ideal conditions for bacterial growth, and are therefore more likely to harbour dangerous bacteria and other disease-causing pathogens like viruses and parasites.
High-risk foods / potentially hazardous foods are foods that are:
- neutral acidity (pH over 4.5 or “mild acids”)
- high in starch or protein
Examples of high-risk foods include:
- meat and poultry
- dairy products
Raw vegetables and fruit can also support the growth of pathogenic microorganisms, especially those that won’t be cooked (e.g. sprouts, melon). Fruits and vegetables can become contaminated if they come into contact with contaminated water, surfaces or equipment; contaminated food; pests; or Food Handlers who are sick or have dirty hands.
Any food that contains one of these foods would also be considered high-risk, so a custard-filled doughnut, salad with cooked chicken or a sandwich with raw sprouts on top would all be considered high-risk foods.
High-risk foods need to be monitored closely with regards to time and temperature to keep bacteria from growing, producing toxins or producing spores. High levels of bacteria or toxins in food can cause food poisoning, while spores protect some types of bacteria from high temperatures, which makes them far more difficult or impossible to destroy in the cooking process.
Between 4°C and 60°C* is the temperature range in which bacteria thrive, which is why it’s called the Temperature Danger Zone. Bacteria are among the fastest reproducing organisms in the world, doubling every four to 20 minutes.
After two hours in the Temperature Danger Zone, the number of bacteria in contaminated food is far too high to consume safely and in some cases, even a small amount of bacteria can cause an infection (depending on the type of bacteria and the health of the individual who ingests it).
*In the province of Manitoba, the Temperature Danger Zone is considered to be between 5°C and 60°C. Everywhere else in Canada, it is between 4°C and 60°C.
Viruses and parasites
Other pathogenic microorganisms, like viruses or parasites, don’t actually grow in food but they can contaminate it; once they are ingested by a person (or animal), they use live cells to increase in number or size.
Eating undercooked meat products is the most common route of parasitic infection, but people can also get parasites from contaminated water (or any food that has been washed in contaminated water), or through cross-contamination. Cooking is the most effective way to control the spread of parasites, so it’s important to know the safe cooking temperatures for the type of food you’re preparing.
Viruses enter the body through the intestinal tract; the most common route of infection is through contact with human hands, which is why hand washing is so important. Other routes of infection include:
- contaminated water
- food washed in contaminated water or seafood (e.g. shellfish) that has been exposed to it
Norovirus is the leading cause of food-borne illness and hospitalizations in Canada. The best way to control the spread of viruses like Norovirus is through hand washing, good personal hygiene and food safety training. Contact CIFS to find out more about food safety training options near you (or visit our food handling course page).
Low-risk foods are foods that do not have good conditions for bacteria or other microorganisms.
Low-risk foods include:
- acidic foods (pH below 4.5 or “strong acids”)
- dehydrated foods*
- salted foods (foods preserved using salt, not just salty foods)
- high sugar foods
- canned or vacuum-packed foods**
*When you add water to dehydrated or dried foods, such as uncooked rice, you add the missing ingredient that bacteria need. This means that dehydrated foods can become hazardous once water is added, so it’s important to keep them out of the Temperature Danger Zone after cooking.
**While uncommon, canned foods can contain a rare kind of bacteria, Clostridium botulinum, which thrives in oxygen-free environments and produces the deadliest toxin known to mankind. Botulinum can’t be detected by sight, smell or taste and has been responsible for some of the deadliest outbreaks of food poisoning in human history.
Find out how botulism spurred a food safety revolution that would forever change the food industry in the United States, Canada and beyond.