Food Additives

INTRODUCTION

Due to the public interest in food additives and consumer queries received in this respect, the Food Advisory Consumer Service decided to compile this general discussion of food additives. The purpose of the discussion is to give an objective overview on the uses and benefits of food additives. Additives are often viewed as harmful chemicals added to food without good reason and also adding unnecessary costs to the food. It is, however, not generally realised that all the material on earth is chemical in nature, not just additives, but all our food and even the human body. Additives differ in their chemical composition and each additive must be judged on its individual merits (cost / benefits).

Food additives play an important role in modern food supply. They add to the variety, convenience, safety, and taste of our food and ensure food availability all year round.

Some additives are derived from natural sources, e.g. lecithin from soya beans. Other additives are man-made e.g. citric acid. Artificial additives can often be manufactured more economically and with more consistent quality than some of their natural counterparts.

WHAT IS A FOOD ADDITIVE?

The food labeling regulations of the UK state:
"A food additive is any substance, not commonly regarded or used as food, which is added to, or used in or on, food at any stage to affect its keeping qualities, texture, consistency, appearance, taste, odour, alkalinity or acidity, or to serve any other technological function in relation to food ..."

Additives lend functional properties to various kinds of foods and are normally catagorised into four classes or groups according to the effects it has on:

1. Physical characteristics (e.g. texture).
2. Sensory characteristics (e.g. taste, smell, colour).
3. Temporal characteristics (e.g. shellfire).
4. Nutritional characteristics.

Additives are usually added to food at very low levels.
Often processing aids are confused with food additives, but they are not additives and serve a different purpose. Examples of processing aids are anti-foaming agents (to prevent excessive foaming of a liquid during boiling) and anti-caking agents (to promote the smooth flow of powders).

CLASSES OF ADDITIVES

1. Affecting Physical/Physico-Chemical Characteristics.

Although these additives are added to improve physical or physico-chemical properties they invariably have an influence on the food's sensory properties.
 

• Thickeners                                                                                                  
  

Such as starches, gums and pectins are used to give body to foods. Every thickener will fulfill a different function and is dependent on the type of food.

• Emulsifiers and Stabilisers                                                                          
  

Used in emulsified food such as salad creams. The emulsifier enables minute drops of either oil or water to be, and remain, dispersed in the other. A stabiliser delays the gradual coalescence of droplets which would otherwise lead to separation.

• Acidulants                                                                                                   
  

Modify the acidity/sour taste required in certain foods, for example sugar confectionery and deserts.

• Clouding agents                                                                                           
  

Used in special classes of soft drinks

• Aerating agents                                                                                       
  

Examples are raising agents used in baking or carbon dioxide gas in carbonated beverages.

2. Affecting Sensory Characteristics
 

Additives in this category, which are used extensively, are flavourings (which could be natural, nature-identical or artificial), sweeteners and colourants (including Tartrazine). A small percentage of the population (up to 1 %) could be sensitive to Tartrazine. Product labelling, as per law, is necessary as well as consumer education about this additive.

Monosodium glutamate (MSG), a flavour enhancer, falls into this group. MSG is a controversial ingredient but only a small percentage of consumers show adverse reactions to the product. The Joint Expert Committee on Food Additives of the U.N.'s FAO and WHO has placed MSG in the most favourable category for a food ingredient. It must also be borne in mind that glutamate is a natural component in many foods, such as mushrooms, tomatoes and peas.

Sulphur dioxide is another ingredient which is used, especially as the most effective anti-browning agent.

Salt is an important flavourant, apart from other characteristics, and it will be the subject of  a future discussion.

• Preservatives.                                                                                           These substances inhibit or retard the growth of micro-organisms which could have a detrimental effect on food spoilage or the safety of food. Examples are sorbates, benzoates and sulphur dioxide. Preservatives should be viewed in the context of food poisoning which is on the increase world-wide.
• Antioxidants.                                                                                                     These are used in oils and foods containing oil or fat to delay the development of rancidity.
• Curing and Pickling Agents.                                                                         These will preserve foods and additives used are salt with sodium nitrate or sodium nitrite (curing of meats) and salt brines and lactic acid followed by vinegar (vegetables).

In this category we find vitamins, minerals and amino acids.

In all populations, even in western society, the intake of certain nutrients is below the required daily allowance (RDA). The specific nutrient will depend on the country and its food habits. When based on scientific evidence, the addition of nutrients to food could have a significant effect on a population's nutritional status.
 

The main concern for food additives is safety. For this reason the type of additives allowed, the food for which it is intended and the levels permitted are controlled by the Foodstuffs, Cosmetics and Disinfectants Act, 1972. South Africa is also one of the member countries, out of about 150, of the Codex Alimentarius Commission which was established in the early 1960's to implement the Joint FAO/WHO (Unite Nations) Food Standards Programmes. This ensures that regulations for South African food is up to world standards. Additives also have to be labeled by law - see also Food Labelling, another of the FACS discussion papers.
It is important that responsible use is made of additives. Any new additive is subjected to sophisticated and costly biological testing before it is released into the market.

F.A.C.S. Scientific Director. 1997.