20.3: The Farm in Our Food

One of the more unfortunate terms in the world of food regulation is filth. A sure way to arouse reader alarm is with the news that more filth has been found in a food than the law allows. Invariably, some readers write outraged letters questioning why “filth” should be allowed in our food at all.

Filth is really incidental matter which gets into food while it’s being grown, harvested, transported, processed, or stored. It’s inevitable that there will always be some in the food supply, and it isn’t really as awful as it sounds. Consider “insect parts,” one kind of filth. Generally these aren’t large juicy bug bits, but more often microscopic fractions of tiny aphids, mites, or weevils, members of the insect world which tend to live in and around the soil and food.

Farms are often near woods and uncultivated lands, and city dwellers sometimes forget that there’s an unpaved world of dirt and leaves, and that worms and beetles and bugs make their homes in the soils where our food grows. As neat and clean as farmers may be, some vestige of the country almost invariably remains with the food.

Pesticides—Competing for the Crop

Wherever there’s a great deal of food, whether harvested or still growing, there is a tempting buffet for various creatures. Indeed, our unbalancing of nature—gathering food plants into concentrated growing grounds for convenience and economy—has led us to turn to pesticides (pest killers). We compete with fungi, insects, and such, for the crop. (To them, of course, we are the pests. But a big dose for them is a small dose for us.)

Pesticides are regulated by Federal law. A special Pesticides Amendment to the Food and Drug Act (passed in 1954) sets forth most of our current policies.

We know a lot about how to identify pesticides in our food, and a lot about how pesticides affect our bodies. So we’re able to make some measurements and do a fair job of determining how much we’re endangered by them. (Risk assessment will be discussed in the next chapter.)

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Traces of pesticides do appear in our food, but it’s not all from the hand of the farmer. Pesticides are used for many purposes, from mosquito abatement to highway weed control, from home gardening to forest conservation.

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The Pesticides Amendment requires the Food and Drug Administration (FDA) to monitor pesticides in our food by sampling our market supplies. The criteria for judging safe levels of pesticides in food are determined by our own experts and by expert committees of the United Nations.

It isn’t possible to prove a negative (i.e., that there’s absolutely no danger), but neither government, nutrition science, nor medicine has seen significant evidence that pesticides in food are causing cancer, birth deformities, or genetic problems. Nor has there been any evidence of illness or death in North America from eating pesticide residues in food. (Accidental overdoses of pesticides inhaled or sprayed onto the skin of farm workers are another matter.)

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Pesticides sometimes can lessen the natural toxins in food. Plants damaged by insects or fungi often make more toxins, e.g., mold damage to some kinds of celery can cause the celery to make 100-times more of a natural toxin—so much, that this “natural celery toxin” can be an occupational hazard for celery pickers and produce checkers.

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According to the FDA, the scant amount of pesticide residues in our food supply is safe. In other words, the fear that we have been and are being poisoned by pesticides in our food isn’t based on solid evidence. Moreover, no one at FDA has any intention of letting the fear become a reality. Improved controls and greater restrictions come into being with any threat, and scientists continue to look for alternatives to pesticides, and use them when practical.

One such alternative is using the pests’ natural predators. But they can take a long time to arrive (just as it took three years for the seagulls to come to Utah to rescue the crops from the plague of locusts in the 1850s), so we usually have to help the situation along. We have, for example, collected parasitic wasps in Iran and brought them to California to successfully combat the olive scale (a pest of olives, plums, apricots, and many other plants) that was damaging many crops.²

Another alternative used extensively in the past and present is the use of crossbreeding to obtain plants resistant to particular diseases. Since the mid-90’s, biotechnology, also known as genetic engineering, has been used to make crops more resistant to viruses or insect pests, and tolerant to weed herbicides.

Integrated Pest Management

Integrated Pest Management (IPM) takes an ecological and customized approach to pest management. The aim is to minimize pesticide use, and to use that which is needed in the safest and most effective way possible.

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One study (part of a Univ. of Calif. IPM Project) found that releasing certain predator mites on cotton crops in late May and early June was more effective than in late June and early July, and that an efficient and accurate way to release them is to mix them with corn cob grit and use a leaf-blower to dispense the mixture.

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IPM integrates various types of controls and strategies, based on the biology of the pests and their predators, the particular crop, local soil and weather conditions, etc. IPM for grapes, for example, might include removal of leaves around developing grape clusters—this has been found to reduce bunch rot and reduce the number of pesticide applications needed to control powdery mildew. IPM for strawberry crops might include:

• Careful monitoring of its pests, to decide if control efforts are needed.
• Using weed control to reduce pest reservoirs.
• Using weather information to predict when the pests will be at the most susceptible stage of their life cycle, so that if pesticides are needed, minimal amounts can be used in a timely way.

When one considers the variety of crops, pests, predators, and local conditions, it’s clear that effective IPM relies on an extensive base of knowledge. Even when one knows, for example, that predator mites can be used to control spider mites in cotton crops, one has to decide when and how to release the predator mites.

Also, when an IPM plan is formulated for a crop, it has to be implemented. Implementation efforts include development of software and databases (e.g., Database of alternatives to targeted pesticides), publications (e.g., IPM for apples and pears), and hands-on workshops (e.g., how to distinguish between spider mites and predatory mites) for growers and farm workers. IPM research and implementation is supported mainly by state and federal funding.