Allergy Society of South Africa

Allergy Conditions

General - Additives and Preservatives

What are Additives and Preservatives?

Additives and preservatives are substances added to food. They can be broadly separated according to their functions, but a single additive may perform a variety of defined functions.


For example:

stop germs and moulds from spoiling food or making it unsafe; an example is sodium benzoate in fruit juices

stop fats and oils from going rancid; for instance, ascorbic acid in butter

stop germs and moulds from spoiling food or making it unsafe; an example is sodium benzoate in fruit juices

stop fats and oils from going rancid; for instance, ascorbic acid in butter
Emulsifiers and stabilisers:
mix foods, particularly oils and water, and prevent them from separating; an example is calcium alginate in ice cream

make food more colourful; two examples are tartrazine and sunset yellow

Flavour enhancers:
bring out flavours in food; a well known one is monosodium glutamate (MSG)

Anti-caking agents:
stops powdery foods from forming lumps (as in salt)

act as a preservative in many foods, but may be added to foods, such as pork, to give a pink colour.


Are Additives and Preservatives Necessary?

In the majority of cases the answer is a definite yes! As our cities grow larger and lifestyles more hectic, it becomes difficult for many people to obtain fresh food. Without preservatives or additives, a great amount of food on shop shelves would "go off" before being bought. For example, bread would last only about two days before becoming stale.


Are Additives Safe?

The vast majority of additives and preservatives appear to be safe. They have been tested by many laboratories throughout the world before being used in foods. However, individuals may be "sensitive" to various additives and preservatives. Government agencies control which substances, and in which amounts, may be used in the production of food. In South Africa the Department of Health controls the use of additives and preservatives.


Who do they affect?

In the majority of cases, individuals with some form of allergy, e.g. asthma, hayfever, urticaria, etc., will be affected by these substances. A few additives and preservatives can affect non-allergic people. Some of these substances cause more reactions than others. For example, reactions to sulphur dioxide and sodium benzoate occur more commonly in asthmatics than reactions to the colorant tartrazine.


What reactions can occur?

Reactions are not "true" allergies as one sees with an egg allergy, but usually a type of chemical reaction. Reactions depend on the type of preservative or additive ingested. These may include vomiting, rashes, hives, a tight chest, headaches, worsening of eczema, and many other symptoms. Combinations of symptoms may give your doctor a strong clue as to the substance causing the reaction


Are there other substances that these reactions may be confused with?

Absolutely! Similar reactions may occur with an allergy to a food such as egg, nuts, etc. Some foods have natural chemicals that may affect you too. For example, fish that's not fresh may have a high level or histamine, cheese may have tyramine, and you may react to the histamine in wine and not the sulphur dioxide!



Which Additives result in Side Effects?

We cannot hope to cover all the additives and preservatives that may result in reactions, but these are some of the more important ones.



Sulphur dioxide and sodium benzoate often cause "tight chests" in individuals who have asthma. Many people also complain of a scratchy feeling at the back of their throats. Although these are the common reactions, others such as rashes may also occur. Sulphur dioxide may be labelled as sodium metabisulphite, potassium metabisulphite, sodium or potassium bisulphite, or sulphite.

Foods that may contain sulphur dioxide include.
(shortened list):

  • some fruit juices,
  • concentrated soft drinks,
  • dried fruit,
  • boerewors,
  • dried wors,
  • wine, beer,
  • some sauces,
  • pickles,
  • hamburger patties.


Foods that may contain sodium benzoate include:
(shortened list):

  • fruit juices,
  • soft drinks,
  • foods with fruit.



These are substances that prevent oily foods from becoming rancid. Some individuals complain of reactions to BHA or BHT. Fortunately, reactions to these substances are not common. Reactions include rashes, hives, and occasionally "tight" chests.



Colorants may be natural or synthetic. Reactions, although not common, can occur to both types. The best known colorant is tartrazine. Tartrazine is an azo dye, so if you react to this colorant, you should avoid all of the azo dyes. Although many people are concerned that they may be affected by colorants, not many individuals are in fact affected. Thus not all asthmatics need to avoid tartrazine. Whether tartrazine or other colorants can result in hyperactivity in children is still controversial.

Foods that may contain colorants include:
(shortened list):

  • fruit juices,
  • soft drinks,
  • sweets,
  • desserts,
  • toppings,
  • syrups,
  • cooking oils,
  • sauces, and,
  • pickles.


Emulsifiers and Stabilisers:

These are substances that keep oil and water mixed, as in mayonnaise. These substances do not cause reactions.


Flavour Enhancers

The most famous of these is monosodium glutamate, commonly called MSG. Eating foods with this additive may result in tight chests in asthmatics. This reaction may occur immediately or 6 to 12 hours later on. A condition called "Chinese Restaurant Syndrome" may occur in any individual. This reaction can occur about 20 minutes after a food containing MSG is eaten on an empty stomach. Typical symptoms include headache, a burning sensation along the back of the neck, chest tightness or pain, nausea, sweating, and a sensation of facial pressure. "Pins and needles" or tingling may be experienced in the limbs or face and head. It is not a common condition.

Foods that may contain MSG include:
(shortened list):

  • Oriental food,
  • packet soups,
  • sauces,
  • soya sauce,
  • seasonings,
  • Aromat.
  • MSG is also thought to occur naturally in mushrooms and tomatoes.



The artificial sweetener aspartame, may cause rashes or hives in sensitive individuals. This sweetener is added to many "low calorie" foods.



Acetyl salicylic acid found in aspirin may result in a "tight" chest or hives in some asthmatics. A different form of salicylic acid can be found in a variety of spices and foods. Some health professionals believe that this form can result in many side effects, including hyperactivity in children. However, this is still controversial.

Foods that may contain salicylic acid include:
(shortened list):

  • ice cream,
  • curry powder,
  • paprika,
  • dried thyme,
  • berries,
  • ginger,
  • almonds,
  • apricot ,
  • oranges,
  • tea, and,
  • honey


How do I know whether I am affected?

This may not always be obvious. In some instances, the reaction will immediately follow the ingestion of an additive or preservative, as with sulphur dioxide and sodium benzoate. In other cases, the reaction may be delayed for 6 to 24 hours.


What can I do to see if I am affected?

You may have to keep a diary and record all the food you eat, the time it was eaten, and when the reaction occurred. You will then need to see if there is a pattern to the reaction. Unfortunately, there is no blood or skin test available to check whether you are affected. Your doctor may suggest a "challenge" with the substance to see if you are indeed affected.


What treatment must I take if I am affected?

Read labels on foods very carefully and avoid all food that contains the preservative or additive that you are affected by. The Food Intolerance Databank* has lists of foods that are "free from" a variety of preservatives and additives. You may have to follow a preservative and additive free diet for at least two weeks to check whether you are indeed affected or not. Your local dietician will assist you in drawing up a suitable diet.



5 Key points to Remember:
1. Preservatives and additives cause chemical and not allergy reactions.
2. Only some asthmatics will react to these substances.
3. There are no reliable tests to confirm sensitivity to these chemicals.
4. Keep a diary of what you eat and when reactions occur to look for a pattern.
5. Read all food and ingredient labels carefully