Published by Australian Academy of Science
When bugs have you on the run Box 3 | Chemicals in food

There are food safety issues other than food-poisoning from microorganisms. In fact, there is a long list of potential hazards posed by modern farming and food-processing technology, although determining the actual degree of hazard is a difficult task.

Pesticides

Since the 1960s, people have worried that pesticides – insecticides, weedicides and fungicides – used on farms and in food-processing premises may find their way into the food chain and adversely affect human health. Scientists remain uncertain about the human health effects of many of the pesticides used widely by Australian farmers. Some that are known to be harmful, such as DDT, are banned in Australia but continue to be used in some other countries.

Antibiotics

Concern has also been expressed that the excessive use of antibiotics in food-producing animals may encourage the spread of drug-resistant microorganisms. According to recent reports, about three-quarters of all antibiotics consumed in Australia are administered to animals. They are added to stock feed because they promote the growth of livestock. Good farming practice demands that antibiotics are not fed to livestock for some weeks prior to slaughter. This allows for sufficient time to minimize the amount of antibiotics in the meat we eat.

Additives

Many foods contain chemicals that have been added during processing. Australian food standards specifically state which additives may be used and the foods which may contain them. A few of the many different types of food additives are listed here:

• anti-oxidants help to prevent fats and oils and the foods containing them from going rancid;
• bleaching agents such as flour whitener;
• colours make foods appear more palatable;
• emulsifiers ensure that mixtures containing oil and water (eg, margarine) don't separate;
• enzymes prevent lollies from crystalising;
• flavours and flavour enhancers like monosodium glutamate (MSG);
• food acids balance sweetness in sweet foods and enhance the fruit flavour;
• free-flowing agents ensure that products such as salt flow freely;
• artificial sweeteners such as aspartame, otherwise known as Nutrasweet, and saccharine; and
• thickeners ensure an even consistency.

Some people may have an adverse reaction to additives. Some additives have been linked by scientists to hyperactivity in children, and some may provoke allergic reactions. The long-term effects of food additives on the body are often unknown and difficult to research. Increasingly, natural alternatives are being discovered that replace the artificial compounds.

Related site

• Antibiotic debate overview (PBS Frontline, USA)

• Chemicals in food (SaferHouses, UK)

Other boxes

Box 1. Common microbial agents of food-poisoning

Box 2. Food preservation

Box 4. Safe cooking