FST 412- Food Toxicity and Safety

Until recently, eating food in modern industrialised countries has usually been regarded as a low risk activity, but several highly publicised food safety scares have raised consumer concerns about the safety of our food supplies (Table 1). Very few of the foods that we commonly eat have been subject to any toxicological testing and yet they are generally accepted as being safe to eat. However, all chemicals, including those naturally found in foods, are toxic at some dose. Laboratory animals can be killed by feeding them glucose or salt at very high doses and some nutrients such as vitamin A and selenium are hazardous at intakes only a few times greater than normal human requirements. Even very common foods such as pepper have demonstrated carcinogenic activity. Toxicity testing of a food or ingredient can tell us what the likely adverse effects are and at what level of consumption they may occur, but by itself this does not tell us whether it is safe to eat in normally consumed amounts. ‘Risk’ is the probability that the substance will produce injury under defined conditions of exposure. The concept of risk takes into account the dose and length of exposure as well as the toxicity of a particular chemical, and is a better guide to the safety of a food. Consequently, any attempt to examine the safety of the food supply should not be based on the question 'Is this food or ingredient toxic?' (the answer is always 'yes'), but rather by finding out if eating this substance in normal amounts is likely to increase the risk of illness significantly, ie 'Is it safe?'