Food Safety Focus (91st Issue, February 2014) – Food Safety Platform
Home-cooking Methods and Food Safety
Reported by Ms. Melva CHEN, Scientific Officer,
Risk Assessment Section,
Centre for Food Safety
Cooking is the practice or skill of preparing food by combining, mixing, and heating ingredients. It helps kill pathogens and improve biological safety, adds flavours to the food, modifies the texture as well as makes them easier to be digested. However, cooking may also generate undesirable substances that are harmful to our health. This article is the first of a series of four on cooking methods and food safety, and will talk about the hazards generated by some common home-cooking methods and ways to reduce the risk.
Hazards Generated by Cooking
The high temperature of frying and baking can cause chemical changes in food and subsequently generate process contaminants such as acrylamide, certain polycyclic aromatic hydrocarbons (PAHs) and heterocyclic amines (HCAs), which have been found to be carcinogenic or potentially carcinogenic to humans. In addition, high temperatures will promote oxidation of fats in food and form undesirable substances such as cholesterol oxidation products (COPs) which can be more injurious to heart and blood vessels than cholesterol. The temperatures of boiling and steaming usually do not exceed 100oC and formation of acrylamide, PAHs and HCAs are unlikely. Even so, repeated and prolonged boiling (e.g. longer than three hours) of meat is not recommended because it may also cause the formation of COPs. Therefore, the control of both the temperature and time during cooking is important.
Home-cooking Tips to Reduce Risks
By modifying cooking times, temperatures and/or other types of handling, the amount of process contaminants formed can be reduced and the foods can be enjoyed in a healthier way.
Shortening frying time
- Blanch (immerse in boiling water for one minute) vegetables and partially boil or steam meats and potatoes before frying.
- For potatoes and other starchy products, go for a light golden colour rather than a darker brown colour.
- Use a food thermometer to gauge the meat temperature so the meat can be removed from heat as soon as it is ready.
Lowering the temperature
- Do not use high heat during the whole frying or baking process.
- Avoid heating oil until it smokes.
Other types of handling
- Trimming visible fats of meats and poultry before cooking may help reduce PAHs and COPs.
- Cutting potato into thick chips/slices which have a lower surface area to volume ratio compared to thinner chips/slices may help reduce acrylamide formation.
- Coating potato chips with batters (e.g. corn starch or wheat flour batters) before frying may help reduce acrylamide formation.
- Replace cooking oil as needed to maintain quality.