I get very confused over the issue of preservatives. I would like to know what kinds are harmful to eat regularly for adults and children.
In general preservatives are not bad for your health. They improve food safety and this is the reason why legislators have authorized their use. Preservatives limit, retard or arrest the growth of microorganisms (e.g. bacteria, yeast, fungi, mould) that are present in or gain entry to the food, preventing spoilage or toxicity. They are used in baked foods, wine, cheese, cured meats, fruit juices and margarine among others.
- Sulphur dioxide and sulphites (E220-228) - help to prevent colour changes in dried fruits and vegetables. Sulphites also inhibit the growth of bacteria in wine and fermented foods, some snack foods and baked goods. Sulphites have also antioxidant properties.
- Calcium propionate (E282) - prevents bread and baked foods from turning mouldy.
- Nitrates and nitrites (sodium and potassium salts) (E249-252) - are used as a preservative in processed meats such as ham and frankfurters to keep the products safe by preventing the growth of botulinum bacteria.
Preservatives are categorised as food additives. In many people´s minds all additives are harmful chemicals, but despite their modern-day associations, food additives have been used for centuries. The preservation of food has been a necessity throughout the ages. Salt, saltpetre (potassium nitrate) and smoke were used to preserve meat, and vinegar to pickle vegetables. Without preservatives our food would be not be as safe as it is today. For example, sulphites help prevent colour changes in dried fruits and vegetables and inhibit bacterial growth in wine, fermented foods, some snack foods and baked goods. Sulphites also have antioxidant properties.
Today, food additives are strictly regulated and go through an authorisation procedure. Authorised food additives are clearly defined substances which have to fulfil strict purity criteria and maximum levels are fixed to protect the consumer. Above all there must be a technological need for their use and a clear benefit to the consumer. The use of food additives is harmonised across the EU, and all approved additives are given an E number. Each has a specific name and number and their use is limited to particular foods. Permitted food additives are broadly classified into several categories according to the functions they perform.
The main uses of additives in foods are to:
- Ensure safety and wholesomeness
- Increase shelf-life
- Amplify or promote sensory qualities (improving texture or consistency; enhance consumer acceptability; assist in food processing, etc)
- Improve or maintain nutritional value
All food additives must have not only a demonstrated useful purpose but also a thorough and rigorous scientific safety evaluation before they can be approved for use.
Since 2003 the European Food Safety Authority (EFSA) is responsible for the evaluation of additives, not anymore the detached EU Scientific Committee on Food (SCF). The Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (Panel AFC) is advising them, too.
Safety assessment of food additives is based on reviews of all available toxicological data, including observations in humans and in animal models. From the available data, a maximum level of an additive that has no demonstrable toxic effect is determined. This is called the no-observed-adverse-effect level (NOAEL) and is used to determine the Acceptable Daily Intake (ADI) figure for each food additive. The NOAEL is expressed in milligrams of the additive per kilogram of bodyweight per day (mg/kg bodyweight/day). The NOAEL is then divided by a safety factor, usually 100, which results in a large margin of safety - for two main reasons: First, the NOAEL is determined in animals, not humans. It is therefore prudent to adjust for possible differences by assuming that man is more sensitive than the most sensitive test animal. Secondly, the reliability of toxicity tests is limited by the number of animals tested. Such tests cannot represent the diversity of the human population, subgroups of which may show different sensitivities (e.g. children, the old and the ill). Again, it is prudent to adjust for these differences.
The ADI provides a large margin of safety and refers to the amount of a food additive that can be taken daily in the diet, over a lifetime span, without any negative effect on health.
The ADI is compared with "average" and "extreme" consumption estimates in the population as whole or in particular subgroups of the population. Provided that intakes for average and extreme consumers are within the ADI, it is unlikely that any harm will result because the ADI is based on a no-observed adverse effect level, to which a large safety margin has been applied. To ensure that consumers are not exceeding the ADI by consuming too much or too many products containing a particular additive, EU legislation requires that intake studies be carried out to assess any changes in intake patterns European Food Safety Authority (EFSA).