Monitoring safe levels of use in food supply

If a substance is deemed safe for use in food, allowable levels are determined .

Experts from the FDA and the FAO/WHO evaluate all the data from the tests and from human

safe food levels in food

exposure.

NOEL is used as the safe level(vsl) for a compound.

The ADI is the amount of substance certainly , on the basis of known facts, that no harm will result .

ADIs may be expressed for a group of related compounds.

The VSL has been suggested for carcinogens for which a dose-response relationship has been established from linear extrapolation.

To set the ADI, NOEL is divided by at least 100 to ensure a margin of safety.

Such a 100-fold margin of safety is necessary to allow for the fact that the number of animals tested is small comparedto the size of the human population that may be exposed.

Further the most sensitive individual is assumed to be 10 times more sensitive than the most susceptible animal.

For carcinogens , a safety factor of 1,000 has been suggested.

Food intake data must then be analyzed to make sure that no population group will exceed the ADI for the substance in question . A variety records , food frequency assessments , food disappearance data, and the FDA market Basket Survey which began in 1961.

Assessing food intake

Each method of assessing food intake has its own inherent errors that may cause estimates of over- or under-consumption of the substance in question. Results from all these methods are pooled to increase the possibility of accurately predicting intake.

Many unanswered questions remain despite these attempts to ensure that the intake of various food constitutes does not exceed the ADI.

For instance, most methods fail to consider seasonal , regional, cultural, and socioeconomic differences in food consumption as well as effects on persons restricted to a few foods, such as infants.

Evaluation of all food substances for toxic hazards is a Herculean task.

One food alone may have 500 minor chemical constituents, in addition to its seven to 10 major ones.

Years could be spent evaluating the safety of all the substances in just one food.

Considering rational approach

Since testing of all the constituents is neither possible no sensible , some rational approach must be considered. One suggestion is the use of a decision tree to categorize substances into low , moderate or high risk .

Factors such as the food's chemical structure and its similarity to other known hazardous materials, metabolism and storage in the body, frequency of use, and the like are used to determine the risk category.

Testing efforts can then be concentrated on the high-risk group.

High-risk substances typically have low LDs values and appear to have immediate or prolonged irreversible effects.

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