Pesticide Levels in Our Food Supply – Are We In Danger?

Q.  Much is said lately about the dangers we face from pesticides in our foods.  And “organically grown” foods grown (hopefully) without any use of pesticides are sold for 2 and 3 times the normal price, in order to save us from this great danger.  Is the danger to our health from pesticides used on our vegetables and fruits real?  Or is it, like so many other things today, hyperbole used to create a market for the organic growers and their marketing agents?

A.  Perdue University’s Cooperative Extension Service is among the most highly respected institutions serving the people’s welfare anywhere in the world.  Following are excerpts from their research paper ppp-22 – Pesticides and Food Safety, written by Fred Whitford, Coordinator of Purdue Pesticide Programs, along with Linda Mason, a Post-Harvest Research Entomologist, and Carl Winder, Extension Food Toxicologist from the University of California at Davis.

It turns out that about 1% of our national fresh food supply is randomly tested very extensively by scientists specifically looking for pesticide toxicity.  This is a very high level of testing, and the findings are VERY comforting and reassuring to those of us who are concerned consumers. 

Summarizing the material reported in Pesticides and Food Safety below, our food supply contains about 1/10,000th as much pesticide as would be needed to produce observable side effects, and if we were to eat this food daily for 70 years we would have consumed about 1 percent of the amount needed to produce observable negative health effects.

I therefore recommend we stop making ourselves sick with worry over pesticides in our commercially-grown food supply and give thanks instead for the best and healthiest food in the world. 

1. Scientists from the Environmental Protection Agency begin the evaluation process by determining the highest pesticide dose that can be fed to laboratory animals to cause adverse health effects but not death. This dose is called the Maximum Tolerated Dose (MTD).

2. The second step in the evaluation process is the selection of the highest pesticide dose that does not cause observable harm or side effects inexperimental animals. This dose level is referred to as the No-ObservableAdverse Effect Level (NOAEL). The NOAEL value can be developed from acute (single incident) or chronic (multiple exposure) studies. The NOAEL is the first safety level.

3. The NOAEL usually is divided by a safety factor of 100 (safety factors range from 10 to 10,000) to take into account individual differences among people and the extrapolation of human health information from animal data. This second safety level is called the Reference Dose (RFD).

4. The RFD generally is expressed in terms of milligrams 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. It is the RFD that is used as the toxicological indicator when pesticide residues are tested on foods designated for human consumption.

5. Next, EPA scientists determine how much of a particular pesticide residue the average consumer might ingest over a life expectancy of 70 years.

foods are analyzed for pesticide residues after they are in table-ready or final food form. The Total Diet Study yields the best insights into actual pesticide residue exposures and takes into account the reduction of pesticide residues which occurs in the course of growing, handling, shipping, processing, washing, peeling, and cooking. Over the last four years, approximately 55 out of more than 200 pesticides have been detected in the Total Diet Study. The nine residues found frequently in the 1989,1990, and 1991 total diet studies are presented in Table 1. The total consumption of foods containing these residues can then be used to estimate daily intake over a lifetime. For example, malathion was detected in approximately twenty percent of the table-ready foods sampled. The residues found on specific food items were multiplied by the amount of the food consumed. In the malathion example, children between 6 and 11 months, young adults between 14 and 16 years, and older adults between the ages of 60 and 65 consumed an average of 0.1, 0.08, and 0.04 micrograms per kilogram of body weight per day, respectively, of this pesticide. Those exposure values were then compared to the RFD criteria established by EPA and the World Health Organization.

The conclusion drawn from the total diet studies is that pesticide residues being detected represent only one percent of the RFD and generally are about 10,000 times lower than the NOAEL. FDA’s monitoring reveals that the “…levels of pesticide residue found in the U.S. food supply are generally below safety limits set by the Environmental Protection Agency.”