Why are there so many chemicals in our food?

I recently ate some great Fuji apples from Sam's Club.

Shiny red, extremely crunchy, with just the right hint of sourness to lift the underlying sweetness.

My curiosity drove me to the label (they came boxed). There, hidden in fine print (our farmers have learned from our bankers!), were the following items:

Treated to maintain freshness with one or more of the following: diphenylamine, thiabendazole, o-phenylphenol, ethoxyquin, 1-methylcyclopropene.

Coated with food grade vegetable and/or shellac based wax.

So I thought I'd structure my regular stroll through WikipediaLand, on a fine Saturday morning, by trying to learn more about these chemicals, and their adverse effects, if any.

Diphenylamine is used as a pre- or postharvest scald inhibitor for apples. Scald, or storage scald, are irregular brown patches of dead skin that start appearing within a week after warming fruit that has previously been preserved cold. Diphenylamine prevents oxidation, which is the principal cause of scald, and hence minimizes storage scald.

The MSDS sheet has the following to say regarding toxicity: "Toxic. Possible mutagen. Possible teratogen. Harmful in contact with skin, and if swallowed or inhaled. Irritant."

Next I turned to Thiabendazole, which apparently is used to control mold, blight, and other fungally-caused diseases. It appears to be relatively innocuous, with slight toxicity in higher doses. There seems to be no evidence for mutagenic or carcinogenic effects.


Similarly, ortho-phenylphenol is also a fungicide, and is apparently found in low concentrations in some household products including spray disinfectants and aerosol or spray underarm deodorants. Its toxicity seems to be controversial, with suppliers insisting that it is safe, while watch-groups suggest otherwise.

Ethoxyquin is another antioxidant, and apparently has been shown to cause mortality in fish. It does seem to present some toxicity concerns.

1-Methylcyclopropene (1-MCP) is an interesting one. From the wikipedia entry:

It is structurally related to the natural plant hormone ethylene and it is used commercially to slow down the ripening of fruit and to help maintain the freshness of cut flowers. The use of 1-MCP in agricultural products including apples, kiwifruit, tomatoes, bananas, plums, persimmons, avacados and melons has been approved and accepted for use in more than 34 countries including the European Union and the United States. Although there are benefits to the consumer including fresher produce and lower cost, there is some concern that consumers may be purchasing fruit that is older than expected.

Based on studies with laboratory animals, no adverse effects are expected to humans who are exposed to end products that contain 1-MCP, although eye irritation may occur if a user does not follow label directions. 1-MCP as a gas is not toxic to test animals.

Moral of the story: Never, ever forget to wash.

And yeah, the title of the post is misleading.