Foodborne Chemicals: Pesticides¹² and Antibiotics

Pesticides

Pesticides (including herbicides) are agents that can both beneficially and adversely affect public health. They are beneficial in that they can allow for increased food production and restrict animal–carried diseases. On the other hand, over 4 billion pounds are applied annually in the United States, so the prevention of unnecessary and accidental exposure through direct contact, or through water and food sources, is essential.

Several common classes of pesticides have the potential for adverse effects on the central nervous system: carbamates (carbaryl), organochlorines (lindane, DDT), organophosphates (malathion), and pyrethroids (permethrin). DEET is also commonly used to prevent mosquito and tick bites, and can be toxic if not used as directed or if ingested; hand–washing after application is essential.

Lindane and permethrin are available by prescription for the treatment of scabies. Permethrin is safer for infants, children, and during pregnancy, and is also available as an antilice shampoo.

It is estimated that 50% of lifetime pesticide exposure occurs in the first 5 years of life.¹³ Developing fetuses and children are at high risk of pesticide toxicity due to their rapid growth and developmental vulnerability. Some pesticides have the potential to disrupt endocrine pathways involving estrogen, androgen, and thyroid receptors. In addition, young children are particularly vulnerable, because they spend more time outdoors, often put their hands in their mouths, and ingest a much greater amount of food per unit body weight. For some pesticide residues, breast milk may contain several times the concentrations found in maternal blood samples.¹⁴

Acute pesticide ingestion can be treated with gastric lavage, charcoal, pralidoxime (for organophosphates), and atropine. Diazepam may also help prevent seizures.

Antibiotics

Untreated pharmaceuticals––such as the antihelminthic morantel, which is used widely in animal agriculture––may pass easily into soil and water supplies once released into the environment.¹⁵ Public health authorities are concerned that antibiotic use on farms may spawn antibiotic resistance. In Oklahoma, turkey, cattle, and chicken farms, and retail meats showed multi–antibiotic–resistant Klebsiella pneumonia bacteria, which could transfer the gene for resistance to E. coli.¹⁶ In developed countries, studies have suggested an association between antimicrobial use in farmed animals and the development of antibiotic resistance in humans.¹⁷ Some experts believe antibiotic resistance is more commonly due to antibiotic use in human patients or to contact with hospital environments.¹⁸ Others have suggested that the development of resistance in humans may be due, in some cases, to antibiotic–resistant microflora of farm animals contaminating products entering the human food supply and passing resistance genes on to human microflora.¹⁹