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Over the last two decades, the organic community has had a love-hate
relationship with food safety issues in general, and pesticide
risks in particular. For the most part, the community has chosen
not to prominently feature food safety as a reason to “buy
organic,” and instead has focused messages targeting consumers
on freshness and taste, and the environmental and soil quality
benefits of organic farming systems.
Anti-pesticide activists, however, have shown less restraint.
They have embraced organic farming as the surest way to reduce
pesticide use and risks. And the message is getting through.
A majority of consumers in virtually all surveys voice significant
concerns over pesticides in food. In “The Packer’s”
2003 Fresh Trends survey, 63 percent of shoppers buying organic
food stated a preference for “fewer chemicals in food”
and 51 percent said organic food is “Better for me/my
family.” The next most frequently cited reason—“Better
for the environment”—was identified by 37 percent
of those surveyed.
For reasons beyond the control of the organic community,
there is now a raging food safety/food quality debate underway
around the world. It is focusing on the impacts of different
farming systems and technologies—conventional farming
vs. biotech vs. IPM vs. organic. John Stossel's 20/20 episode
of February 2000 ("How Good is Organic Food?") and
recent NOP rule-related PR from conventional ag interests
shows how low those threatened by the success of organic farming
will go in trying to shake consumer confidence in organic
food. Hopefully the organic community now realizes that the
industry’s critics must not be allowed to set the tone
and direction of this very important debate.
Activists opposing genetic engineering (GE) around the world
have been criticized in the media as paranoid and anti-progress.
Some have stumbled when asked, "Well, if GE is not the
answer, how would you solve today’s food production
and food security challenges?” With increasing frequency,
activists point to organic farming as the more desirable technological
path. Proponents of biotech have not been bashful in responding.
This debate is long over due and ultimately should be constructive.
There are profound differences between the principles driving
today’s GE applications in agriculture vs. the principles
underlying organic farming. The sooner the public understands
these differences and decides which set of principles should
shape their food future, the sooner the country can progress
toward more coherent national food, farm, and technology policies.
Today’s muddling serves no one well.
New science supports a positive food safety
message
There is new information on both the exposure and toxicity
side of the pesticide risk assessment equation. Much new data
on pesticide residues in food has emerged as a result of the
passage of the Food Quality Protection Act (FQPA) in 1996.
This historic bill directed the U.S. EPA to conduct a reassessment
of all food uses of pesticides, taking into account the heightened
susceptibility of infants and children, the elderly, and other
vulnerable population groups.
Why the focus on risks to infants and children? Because kids
consume more food per kilogram of bodyweight than adults do
and eat a much less varied diet. As a result, exposure to
a pesticide from consumption of a given food is greater per
kilogram of infant/child bodyweight compared to adults (National
Research Council, 1993). Moreover, exposure to some pesticides
during infancy, even at very low levels, can lead to serious
life-long consequences if the pesticides disrupt hormone-driven
developmental processes.
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"The foods most likely to contain
residues of high-risk pesticides are apples, pears, peaches,
grapes, green beans, tomatoes, peas, strawberries, spinach,
peppers, melons, lettuce, and various juices." |
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In the early 1990s, surprisingly little was known about the
frequency or levels of pesticides in food as actually eaten.
Then-existing government data on residues had been collected
as part of tolerance enforcement programs and represented residues
at the farm gate, prior to washing, shipping, storage, marketing,
and preparation. Relatively insensitive analytical methods were
used.
To improve the accuracy of FQPA-driven pesticide dietary
risk assessments, Congress funded a new USDA program in 1991,
the “Pesticide Data Program” (PDP). By design,
the PDP focuses on the foods consumed most heavily by children,
and food is tested, to the extent possible, “as eaten”
(Agricultural Marketing Service, 2002). (A banana or orange
samples are tested without the peel; processed foods are tested
as they come out of a can, jar or freezer bag.)
Ten years of PDP testing has greatly enhanced understanding
of pesticide residues in the US food supply. About a dozen
foods are tested annually. Some 600 to 650 samples are tested
of each fresh or processed food, reflecting domestic production
and imports roughly proportional to their respective share
of overall consumption. Plus, market claims associated with
a given food item, such as “organic,” “IPM-grown,”
“No Detectable Residues” or “pesticide free,”
are recorded roughly in proportion to their occurrence in
retail market channels (Baker et. al., 2002). As a result,
PDP results make possible comparison of the distribution and
frequency of pesticide residues in domestic vs. imported foods,
across food groups, and by market claim (Groth, et al., 2000).
The first-ever analysis of pesticides in organic vs. conventional
foods was published in the peer-reviewed journal Food Additives
and Contaminants in early 2002 (Baker et al., 2002). I was
among the authors. The full team included Brian Baker, the
Organic Materials Review Institute’s director of research,
Ned Groth of Consumers Union, and Karen Lutz Benbrook. The
paper analyzed six years of PDP data, 10 years of California
Department of Pesticide Regulation (DPR) data, and results
of Consumers Union testing of four crops. The PDP data covered
program years 1994-1999, and the DPR data, 1989 through 1998.
An overview of pesticide residues in conventional
and organic foods
Some major food groups—most oils, dairy, meat, and
poultry products—contain few detectable pesticides and
contribute very modestly at the national level to dietary
exposure and risk. About a dozen pesticides are present routinely
in fresh produce and juices at levels that pose significant
risks. Despite much new data and more refined risk assessment
methods, several key children’s foods still contain
worrisome pesticide residues six years after passage of the
FQPA (Consumers Union, 2001). The foods most likely to contain
residues of high-risk pesticides are apples, pears, peaches,
grapes, green beans, tomatoes, peas, strawberries, spinach,
peppers, melons, lettuce, and various juices.
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Nearly three-quarters of the fresh fruits and vegetables
(F&V) consumed most frequently by children in the United
States contain residues and almost half the F&V samples
tested from 1994-1999 in the PDP contain two or more residues
(Baker et al., 2002). In general, soft-skinned fruit and vegetables
tend to contain residues more frequently than foods with thicker
skins, shells, or peels.
The pattern of residues found in organic foods tested by
the PDP differs markedly from the pattern in conventional
samples. Conventional fruits are 3.6 times more likely to
contain residues than organic fruit samples and conventional
vegetables are 6.8 times more likely to have one or more detectable
residue.
Compared to organic produce, conventional samples also tend
to contain multiple residues much more often. Imported foods
consistently contain more residues than domestic samples,
regardless of market claim.
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"A few pro-pesticide activists
have gone to great lengths to convince consumers that
pesticide residues in organic foods are as risky as those
in conventional foods. Fortunately, these claims do not
pass the laugh test." |
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Averaged across the PDP and DPR data sets, just under 7 percent
of positive organic samples and 54 percent of positive conventional
samples contained multiple residues. The average positive conventional
apple sample contained 3.2 pesticides, peaches contained 3.1
residues, and celery and cucumber contained 2.7 (Baker et al.,
2002).
Data from DPR testing in 1999 and 2000 shows that conventional
food is more than five times more likely to contain residues
than organic samples. It is worth noting that organic farmers,
processors, and retailers are doing a better job in preventing
fraud, pesticide drift and other inadvertent residues, given
the downward trend in the frequency of residues in organic
foods. In 1996-1998 testing by DPR, just over 12 percent of
organic samples tested positive on average, while 7.1 percent
contained detectable residues in 1999-2000. There was little
change in the frequency of residues in conventional foods,
which averaged 38.3 percent annually from 1996-1998 and 40
percent in 1999-2000.
There is growing interest in Europe in comparing the residues
in food produced by conventional vs. organic farmers. The
British government reported residue findings in organic food
samples for the first time in 2001.
The analytical methods used by the British Pesticide Residue
Committee are not as broad or sensitive as those used in the
PDP, and hence the percent of samples testing positive are
lower in both conventional and organic foods. But the differences
between conventional and organic foods remain. Over 250 samples
of organic foods have been tested by the PRC since 2001—more
samples than tested by the PDP over 10 years. Just under 27
percent of all samples tested positive, while 3.6 percent
of organic samples contained a detectable pesticide residue.
Hence, based on British testing, conventional foods are 7.5
times more likely to contain detectable residues than organic
foods.
Pesticide toxicity
Implementation of the FQPA triggered an explosion in toxicological
and risk assessment research on the developmental effects
of pesticides. During fetal development and the first years
of life, infants are much less able to detoxify most pesticides
and are uniquely vulnerable to developmental toxins, especially
neurotoxins, given that the brain and nervous system continue
developing through about age 12 (National Research Council,
1993; Eskenazi et al., 1999).
New toxicological data have forced downward by one to two
orders of magnitude the allowable levels of exposure to various
pesticides found in food (Office of Pesticide Programs, 2002;
Gray et al., 1999). The EPA has had to phase out hundreds
of food uses of relatively high-risk pesticides (mostly organophosphate
insecticide uses) in order to meet the FQPA’s new “reasonable
certainty of no harm” standard (Consumers Union, 2001).
In the last decade much new evidence has emerged on the mechanisms
through which pesticides can disrupt development as a result
of even very low exposures. Literature through early 1999
is summarized in a special issue of the journal Toxicology
and Industrial Health (Colborn et al., 1999). Just a few examples
follow focusing on research published since the 1999 review.
A review article published in San Francisco Medicine in November
2002 targets lay audiences and provides a useful update on
recently published research findings on endocrine disruptors
and human health, including several studies on pesticides
(Myers, 2002). University of California-Berkeley School of
Public Health scientists found that exposures to pesticides
during pregnancy significantly heightened risk of children
developing leukemia and that the more frequent the exposures
and the earlier in life, the greater the increase in risk
(Ma et al., 2002). A team in the Department of Preventive
Medicine, University of Southern California, found that exposure
to pesticides in the home during fetal development increased
the risk of Non-Hodgkin’s lymphoma, with odds ratios
as high as 9.6 for Burkitt lymphoma (Buckley et al., 2000).
A study in Ontario, Canada, confirmed that exposures to pesticides
three months prior to conception and during pregnancy increased
the risk of spontaneous abortions (Arbuckle et al., 2001).
Research supported by the French Ministry of Environment documented
clear linkages between exposures to pesticides commonly used
in grape vineyards and long-term adverse cognitive effects
(Baldi et al., 2001). Cognitive performance was compared in
a group of children living in an upland agricultural region
in Mexico where substantial pesticide use occurred, compared
to a similar cohort in a nearby village. Children exposed
to pesticides had lessened stamina and attention spans, impaired
memory and hand-eye coordination, and greater difficulty making
simple line drawings (Guillette et al., 1998).
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"Conventional fruits are 3.6
times more likely to contain residues than organic fruit
samples and conventional vegetables are 6.8 times more
likely to have one or more detectable residue." |
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Recently published work on the developmental neurotoxicity of
the most widely used insecticide in the United States, chlorpyrifos,
showed that this organophosate (OP) targets neural cell replication
and differentiation, as well as the functioning of glial cells
(Qiao et al., 2002). The authors conclude that exposures to
this OP during the first few years of life are likely a greater
risk than during fetal development, although prenatal exposures
appear to disrupt the architectural organization of specific
regions in the brain and the development of the fetal liver.
Antiandrogenic pesticides have been shown to cause demasculinization
in several species by blocking the receptor sites needed for
male sexual hormones to perform their normal functions during
development (Baatrup and Junge, 2001; Gray et al., 1999).
The most compelling new study to appear on pesticide dietary
risks in a long time was published online on October 31, 2002,
in the highly respected journal Environmental Health Perspectives.
A team based at the University of Washington’s School
of Public Health and Community Medicine carried out the research.
The research assesses the difference in organophosphate (OP)
residues and risk faced by two to five year-olds consuming
a diet composed of mostly organic foods vs. conventional foods
(Curl et al., 2002).
The team found that children consuming mostly organic foods
over a three-day period had much lower mean levels of organophosphate
(OP) insecticide metabolites in their urine—in fact,
children consuming conventional food had 8.5 times higher
average levels than children eating a mostly organic diet.
The study was carefully designed to avoid other potential
confounding variables. The children came from similar socio-economic
backgrounds; households with recent use of pesticides in the
home were excluded from the study; and rigorous sampling and
double-blind testing protocols were used. The research team
concluded that, “Consumption of organic produce represents
a relatively simple means for parents to reduce their children’s
exposure to pesticides” (Curl et al., 2002).
Organic farmers and consumers are not the only ones that
should rejoice at these findings. Conventional farmers adopting
biointensive Integrated Pest Management systems can also markedly
reduce OP insecticide use. Extensive evidence compiled by
the EPA over the course of implementing the FQPA suggests
that by cutting out all OP sprays within 90 to 120 days of
harvest on major kids’ foods, OP residues will largely
if not fully disappear from fresh produce. This is also good
news for EPA, which can now confidently predict major progress
in reducing OP risks following a relatively small number of
regulatory actions targeting less than two dozen foods.
Why organic food sometimes contains residues
Many people wonder why between 10 percent and one-quarter
of organic F&V samples contain residues of synthetic pesticides.
Like transgenic DNA, pesticides are ubiquitous and mobile
across agricultural landscapes. Most positive organic samples
contain low levels of pesticides used on nearby conventional
fields. They move onto organic food via drift or through use
of contaminated irrigation water. Soil-bound residues of persistent
pesticides account for a large portion of residues in root
crops and squashes. Cross-contamination with post-harvest
fungicides applied in storage facilities is a major cause
of low-level fungicide residues (Baker et al., 2002). The
small percent of samples sold as organic and found to contain
relatively high levels of residues likely arise from inadvertent
mixing of produce, laboratory error, mislabeling, or fraud.
A few pro-pesticide activists have gone to great lengths
to convince consumers that pesticide residues in organic foods
are as risky as those in conventional foods. Fortunately,
these claims do not pass the laugh test. Expanded residue
testing of botanicals and biopesticides would be needed to
decisively settle the empirical issues behind such specious
claims. Settling this artificial controversy would mean less
testing to better understand significant pesticide dietary
risks, a tradeoff thus far rejected by government regulatory
and research agencies.
By volume, major pesticides used on both organic and conventional
farms include sulfur, horticultural/petroleum distillates
and oils, and copper-based fungicides. There are some formulations
of these pesticides approved for organic production and many
others available to conventional growers. These pesticides
are used in similar ways for comparable reasons on organic
and conventional fruit and vegetable farms. Sulfur is almost
certainly the most common pesticide residue present on conventional
and organic F&Vs, but it is never tested for because it
is exempt from the requirement for a tolerance and poses essentially
no risk through the diet. Copper is also not tested for because
of tolerance exemptions and the fact that copper is an essential
nutrient and harmless at the levels ingested as food residues.
Organic farmers also rely on Bacillus thuringiensis insecticides,
pheromones, and products that coat produce with nontoxic,
biodegradable materials (e.g., soaps and clays). Residues
of these pesticides are rarely tested for because there are
no tolerances to enforce and no basis for food safety concerns,
given how these products are used in production agriculture.
While there were once several toxic botanical insecticides
on the market and approved for organic production, only one
remains in relatively common use – pyrethrins. Pesticides
containing pyrethrins are indeed toxic but they degrade rapidly
after spraying and hence rarely leave detectable residues.
They are also applied at very low rates, on the order of one
to two one-hundredths of a pound per acre; OP insecticides
are applied at rates 50 to 100 times higher. Other botanicals
of possible concern include rotenone and sabadilla. The most
recent survey of organic farmers carried out by the Organic
Farming Research Foundation found that only 9 percent of 1,045
farmers applied botanicals regularly (mostly pyrethrins and
neem), and that 52 percent never use them, 21 percent use
them rarely, and 18 percent “on occasion” (Walz,
1999).
Two closing thoughts
To the extent consumers become aware of recently published
research findings on pesticides in food, it is likely to reinforce
already deep-set concerns. It is now clear that purchasing
organic food is a reliable way to reduce exposure to pesticides.
Less exposure means greater margins of safety. While toxicologists
and risk assessment experts can argue until the cows come
home over whether 0.05 ppm of pesticide X, Y, or Z is safe
or unsafe, many consumers are looking for practical ways to
reduce personal risk loads. Consuming organic food is clearly
one way to do just that.
Several times in recent years, the USDA has stated publicly
that organic food is no safer than any other food. Even more
frequently and assertively, the USDA has claimed that GE foods
are fully tested and pose no risks. Bush administration and
USDA leaders are puzzled why so many people around the world
are unwilling to accept these claims. The credibility of the
US government and confidence around the world in US food exports
rests upon whether food safety conclusions reached by the
USDA are grounded in sound science and consistent with the
latest research findings. Clearly, the USDA needs to look
anew at recent data on pesticide residues in conventional
and organic foods and reconsider its message.
For the full text of this article and accompanying data tables,
see http://www.biotech-info.net/Ecofarm_Food_Safety.pdf.
Additional information about food quality and food safety
can be found at www.biotech-info.net. Chuck Benbrook can be
reached at Benbrook Consulting Services, 5085 Upper Pack River
Road, Sandpoint, Idaho 83864; tel. 208-263-5236; email benbrook@hillnet.com.
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