In Australia, reports of illness caused by the presence of hazardous chemicals in food are much rarer than illnesses associated with pathogenic microorganisms. However, misuse of chemicals agriculturally or during food processing can cause illness. Harmful chemicals can also be present in food naturally or by environmental contamination. Additionally, substances found naturally in food can cause illness when eaten by people who are allergic or sensitive to them.
Types and sources of chemicals in food that may cause illness if eaten include:
• proteins or other substances that may cause allergic reactions (e.g. peanuts)
• approved food additives, such as chemical preservatives, used incorrectly
• residues from cleaning and sanitising chemicals
• deliberate or accidental addition of chemicals not approved for use in food
• chemicals leaching from packaging into food
• environmental pollutants from industrial waste, such as mercury or dioxins in fish
• agrochemicals such as pesticide residues, herbicides and veterinary chemicals
• toxins of microbial origin such as mycotoxins in peanuts and histamines in fish
• naturally occurring plant toxins such as glycoalkaloids in potatoes.
Illnesses associated with chemicals in food can be caused by eating a high dose of a chemical contaminant over a short period (i.e. an acute reaction) or by eating a low level of a chemical contaminant over a long period of time (i.e. a chronic reaction).
There are many different chemicals used in food businesses. Due to the care taken when handling these chemicals in Australian food businesses, cases of health issues associated with them are very rare here. However, there have been food recalls in Australia owing to accidental contamination or misuse of approved additives.
Food additives
In Australia, all food additives undergo rigorous safety assessments before being listed in the Code as an approved substance. The Code specifies the chemicals permitted for use and also which classes of food they are permitted in and at what level. You can find this information in the following standards:
• 1.3.1 Food Additives – for example: preservatives, artificial sweeteners, acids, food gums, colours and flavouring agents.
• 1.3.2 Vitamins and Minerals – this does not include substances naturally present in foods – only those that are added separately.
• 1.3.3 Processing Aids – for example: lubricants, bleaching and washing agents, filtering and clarifying agents, and antifoam agents.
Certain substances are more of a food safety issue than others. If you add vitamins or minerals to foods, you need to be aware that some can be toxic if the levels are too high (e.g. iron and Vitamin A). Nitrite preservatives are also toxic at high levels and may cause death within minutes of being eaten because the body’s ability to transport oxygen in the bloodstream is affected. Some people are sensitive to sulphite preservatives and the presence of more than 10 mg/kg of food must be stated as a warning on product labels.
Specific control measures for safe use of chemicals include:
• Only use substances permitted in the Code for your specific product types – seek advice from a technical expert, such as a product development consultant or your local food authority if you have difficulty finding the information in the Code.
• Do not exceed the permitted levels specified in the Code – seek advice if you are unsure how to calculate appropriate concentrations for your products (never guess); ensure that only staff that have received specific training handle these substances; weigh out the chemicals separately from other ingredients following prepared recipe sheets.
• Ensure you store chemicals safely – keep them separate from food ingredients and ensure storage containers are clearly labelled.
• Provide your staff with training on how to correctly weigh out or measure chemicals, and ensure that weighing equipment is maintained according to the manufacturer’s instruction.