Lesson E4 - Food Additives Flashcards Preview

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Flashcards in Lesson E4 - Food Additives Deck (27):

Food additives are

substances that are added to food to improve appearance, texture, and storage
of food. This is the classical definition, but a broader definition would include additives to
improve nutritive value, e.g. vitamins and minerals


additives are those

that are added inadvertently as a result of the growing, manufacturing and
storage processes


These unintentional additives are often termed contaminants and the amount
that is present in food is

limited by regulations


Additives are convenience substances and are not

necessarily required.


The risk/benefit ratio of additives must be carefully determined. The
techniques used to determine risk/benefit is to study the toxicity in animals and then extrapolate
the results to humans. The limitations are:

The risk/benefit ratio of additives must be carefully determined. The
techniques used to determine risk/benefit is to study the toxicity in animals and then extrapolate
the results to humans. The limitations are:


Some of the principles concerning food additives which have been adopted by the World Health
Organization are:

1. Use of additives is justified if they enhance or maintain the quality or acceptability of food.
While this statement has merit, it does not address the risk/benefit assessment of the
additive. If the risk is high, then no level of benefit would warrant use of the agent.

2. Additives should be used only in quantities sufficient to obtain stated ends.

3. Additives should be pure. Additives often contain impurities, and in some cases the
toxicity has been associated with the impurity. Thus, toxicological evaluation of the
impurity must be conducted.

4. Toxicological evaluation of additives should be undertaken. Society has used a number of
additives for centuries. Should these compounds be exempt from toxicological assessment?
If an agent has been used for 200 years, is it necessarily without risk? A reasonable
position would be to gather the available information on a specific compound and utilize that data to determine potential risk and the need for further study.

5. Special groups should be considered, i.e. those who may be expected to eat a large amount
of a particular substance. Risk assessments are determined on the concept that individuals
exhibit similar behaviour or dietary habits. In other words, we do not eat ten bags of potato
chips each day. Unfortunately, some individuals do eat ten bags of potato chips each day
and the risk assessments must be such as to include these individuals. A good example of
this concept occurred in the early 1970's. There were a number of deaths due to cardiac
causes in individuals with no apparent risk factors for heart disease. The causative factor
was found to be cobalt chloride, a compound which inhibited the heart muscles from
functioning. Cobalt chloride was added to beer to control the head (foam) on the glass of
beer. Risk assessments determined that individuals would need to consume 24 beers every
day for long periods of time to receive a toxic dose of cobalt chloride. Unfortunately, some
individuals do and some of these succumbed to the effects of cobalt chloride. The agent is
no longer added to beer



This class of additives includes substances such as

spices, flavouring agents, essence of
smoke, synthetic flavours, etc.



Colouring agents are organic dye stuffs. Most are well evaluated, but one is never sure of
the carcinogenic potential. It is fortunate that colouring agents are used in small amounts as
they may have one of the greatest potentials for toxicity among

food additives


It has been claimed that since food colouring agents can be considered organic dye stuffs
derived from coal tar, and since coal tar is a carcinogen, all artificial food colours are
carcinogens and only colouring agents from natural sources

should be used.


Colours are added to give food an

appetizing appearance;


Texture Agents

This class of agents are added to improve or impart a specific texture to a product. Silicates
are added to flour and flour products to keep them free flowing. Emulsifying and

thickening agents (gums, agar, alginates) are added to a number of frozen foods, e.g. ice
cream and sherbet. Milk shakes contain a thickening agent.



The use of agents to preserve the quality of food is one of the more rational uses of
additives. It allows the delivery of food to distant destinations and ensures the appropriate

quality of the food for the consumer. In most cases, the benefit outweighs the risk.



Historically, sodium chloride was the first preservative used. It is still used today. It is
effective as a

a preservative, especially when coupled with smoking or drying


Smoke is an age-old method of preserving food, mainly meat. It is also used to impart

flavour to food.


Sodium benzoate is added to food as it has antibacterial and fungistatic activity, thus
preventing the spoilage of



Parabens are derivatives of sodium benzoate and are used for the same purpose, and can be
considered similar to

sodium benzoate


Propionic acid and its salts are used as preservatives. These compounds are more active
antibacterials at lower pH values as they function as the

free acid


Antibiotics would be the most effective antibacterial

food addtives


Sugar is one of the earliest methods of food preservation. In syrups, the high sugar content
will retard bacterial growth through

osmotic effects


There is considerable controversy surrounding the use of

nitrates in food! (SH I love you so much you are going to kill this exam- I cant wait to see you and kiss you- now keep studying)


There have been
attempts to reduce the use of nitrites. Sodium nitrite is added to meat for two reasons:

colour – NO2

+ myoglobin → nitrosomyoglobin (red in bacon and ham); and (b) it inhibits
growth of Clostridium botulinum, thus is used as a preservative in prepared meats.


Clostridium botulinum produces a toxin which leads to botulinum poisoning,

a serious condition


Sulphur dioxide (SO2) is used to prevent mould formation in wine. If wine consumption is
high, then an individual may get SO2 toxicity; related to

vitamin B1 deficiency


Antioxidants prevent the oxidation and thus rancidity and discolouration of foods. They
improve storage and

quality of the product


Water soluble antioxidants are added to reduce the oxidation of carbohydrates, e.g.
browning of fruit, etc. The agents most commonly used are ascorbic and

citric acids.



The purpose of sequestrants is to bind




Three agents have been used in addition to sugar –

– cyclamates, saccharin and aspartame.