Vol. 536 No. 4
162 Mr. J. Bruton asked the Minister for Health and Children if toxicology testing of chemicals used in food production encompasses a sufficient varied population of animals to ensure that findings of possible toxins is assessable in a manner that would be beneficial for the variety of humankind. [14478/01]
Chemicals used in food production must undergo rigorous safety evaluation before they are approved. This research must include toxicological tests or tests to determine whether a substance is harmful to humans. In these tests the chemical is administered to laboratory animals, usually mixed with their diet.
There are basically two types of testing. First, the animals are exposed to concentrations of the chemical being tested that are much higher than will occur in human food. The animals are then subjected to observation and histopathological examination of tissues and organs. These tests are designed to elucidate the mechanism of intoxication and the likely sites of action within the body.
The second type of test is the determination of a threshold level for the chemical. This requires the administration of decreasing doses of the chemical until a level is achieved whereby there is no effect on the animal. These threshold values are often called no effect level, also known as NOEL, or no adverse effect level, also known as NOAEL, although other measures do exist. In all of these tests sufficient animals are used to comply with the existing international animal testing regimes.
Toxicological tests are designed to give information on any possible effects from short-term or long-term exposure to the proposed food chemical. Some effects include whether it may have any potential to cause cancer, also known as carcinogenicity, or affects male or female reproduction or the development of the embryo or the foetus if consumed by a pregnant woman which is called teratogenicity.
Other effects include the mutagenic potential of the compound or mutagenicity. That is its ability to interfere with genetic material in the body which could lead to the development of cancer or adverse effects in future generations. In this regard different tests may use different animal species or sub-populations depending on the question that is being answered.
Chemical safety assessments are carried out by bodies such as the European Unions' Scientific Committee on Food or the WHO/FAO Joint Expert Committee on Food Additives and Contaminants. Safety assessments are only carried out when there is sufficient data based on many toxicological studies often carried out by independent researchers in many countries. The safety assessment will always try to set a threshold level for human exposure to the chemical being evaluated. To do this the threshold level in animals is reduced by a safety factor based on the likely action of the chemical on the human body. This results in such threshold measures as acceptable daily intake, tolerable weekly intake or an acute reference dose which is also referred to as ArefD.
