Food Safety and Food Chain

Due to consumer concerns regarding potential residues on foods, both international and national regulators have developed an extensive system of tests to protect consumers from potential harm while providing the finest fruits and vegetables. The registration of a pesticide for use in gardens or farm fields requires an assessment of the potential negative effects of that pesticide on human health. To anticipate how a pesticide might impact human health, laboratory animals such as mice and rats are exposed to varying dosages of the pesticide in their foods – from very minimal to extremely high levels. Toxicologists then evaluate the observable effect(s) of consuming known quantities of the pesticide on acute, sub-chronic, chronic, mutational, reproduction and neurological effects in the test subjects. Information gained from such a test is evaluated by toxicologists and medical experts to determine potential human effects.

1. Toxicologists from governmental authorities, such as United States Environmental Protection Agency (U.S. EPA), European Union (EU) Commission and the Japan Ministry of Health, Labor and Welfare (JMHLW); and international organizations, such as the United Nations Food and Agriculture Organization (FAO) and World Health Organization (WHO), begin the evaluation process by determining the quality of toxicological studies in terms of compliance to study guidelines and Good Laboratory Practice (GLP).
2. The second step in the evaluation process is the selection of the highest pesticide dose that does not cause any adverse effects to experimental animals. This dose level is referred to as the No-Observed Adverse Effect Level (NOAEL). The NOAEL value can be established from single or multiple exposure studies.
3. The NOAEL usually is divided by a safety factor of 100 (safety factors range from 10 to 1,000) to take into account individual differences among people and the extrapolation of human health from animal data. This value is known as the Acceptable Daily Intake (ADI). In the United States, the term ‘Reference Dose (RfD)’ is often used instead of ADI.
4. The ADI generally is expressed in terms of milligram of a pesticide consumed per kilogram of body weight (mg/kg) per day. It is the amount of a pesticide residue that, if ingested daily over a 70-year lifetime, a human could consume without expecting any health-related problems. The ADI is used as the toxicological indicator when pesticide residues are tested on foods designed for human consumption.

It must be emphasized that the ADI does not represent a level of toxicity. Individuals may, on occasion, exceed the ADI so long as their average daily intake is below the ADI. Although called an acceptable daily intake, the ADI should always be compared with average intakes over prolonged periods - not with day to day intakes.