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er rodent carcinogen. Orange and mango juice have up to 40 parts per million
of the carcinogen limonene. Our old friend, the carcinogen caffeic acid, is a nat-
ural constituent of a dozen different spices, as well as being found in produce
ranging from apples, grapes, and pears to lettuce, carrots, and potatoes. A
separate volume could be written on the dangers of spices alone, most of
which contain known carcinogens. For example, basil and fennel each contain
over 3,000 parts per million of the rodent carcinogen, estragole, while nutmeg
contains as much safrole. Black pepper contains both safrole and limonene. I
will finish with a hot cup of roasted coffee, which in addition to containing
caffeine, also contains caffeic acid and catechol. Throughout history our civi-
lization has been, and will continue to be, constantly exposed to a multitude
of natural carcinogens in all of our produce and spices, at concentrations
thousands to millions of times higher than any artificial chemical!
The point of this book is not to catalogue every natural carcinogen known
to modern science. If that is the goal, the interested reader should consult the
exhaustive literature by Dr. Ames listed in the references. My point is that
these known toxins are widespread in our produce yet we already know that
eating these same fruits and vegetables is actually good for your health. Why?
One excellent food that illustrates this dichotomy is the peanut. First, there
is a well-documented physical hazard associated with children who choke on
them. Should we label peanuts to protect us from these acute hazards, which
probably killed more children than exposure to any trace level of pesticide on
the same peanut? Secondly, some individuals are acutely allergic to peanuts or
any food containing them. This is a serious problem for those sensitive indi-
viduals, and efforts continue to be made to label foods containing peanuts to
alert these individuals. The main toxicological problem of peanuts and prod-
ucts made from them, such as my personal dietary staple, peanut butter, is the
problem of contamination with molds. Aflatoxin, found in moldy peanuts, is
the most potent human carcinogen known and is well documented to pro-
duce liver cancer.
To eliminate moldy peanuts, synthetic fungicides are used. The scientific,
CHEMICALS PRESENT IN NATURAL FOODS 75
ethical, moral, and legal dilemma facing us is that many effective fungicides
test positive for inducing cancer, whether the tests are done in laboratory ani-
mals or in vitro. Some of the most widely acclaimed tests use bacteria to deter-
mine if the chemical can damage the bacterial DNA. An effective fungicide is
usually toxic to fungal cells and the relatively closely related bacteria, so it is
no surprise that these potent chemicals test positive in these tests when the
chemicals are given at high doses. Since they are synthetic chemicals, they are
banned from use. Banning fungicides does remove this chemical carcinogen,
but it also allows mold to grow and produce mycotoxins such as the carcino-
genic aflatoxins. Mother Nature does not have to get FDA approval to evolve
plants that produce carcinogens such as aflatoxin. Are we safer or more at risk
because of this policy?
I should point out that many of the earliest fungicides were indeed haz-
ardous to human health and were only developed because there was a positive
benefit to risk ratio that is, they did more good than harm. These included
chemicals whose main toxic ingredients were mercury or arsenic. As dis-
cussed in Chapter 3, early pesticides containing these toxic metals were
probably the culprits partially responsible for some of the ecological prob-
lems discussed in Silent Spring. It is worthwhile at this point to briefly review
the toxicology of the mycotoxins, since many were first described because
they caused disease in humans and were the impetus for developing chemical
fungicides. What was the trade-off?
Mycotoxins are biologically active chemicals produced by various species
of fungi and molds. The molds that produce mycotoxins are often found as
common contaminants of grains or grasses. The production of mycotoxins by
these organisms may only occur under specific environmental conditions,
such as defined temperature or humidity, or after mechanical damage. When
farming or storage conditions are not optimal, mold may form. This was a
major historical problem that was largely eliminated by the development of
fungicides. Certain species of fungi most often produce mycotoxins in stored
grains, whereas other fungal species most often produce mycotoxins in plants
that are in various stages of growth. As a group, mycotoxins represent some of
the most potent toxins presently known to modern toxicology. Many are
potent carcinogens, mutagens, and/or teratogens, with aflatoxin being one of
the more potent carcinogens known. These agents have even been suggested
as agents of chemical warfare or bioterrorism (see Chapter 10). These are not
sinister chemicals synthesized by man but are natural components of our
environment.
For regulatory purposes, mycotoxins are considered contaminants, where-
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