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Campylobacter
In November 2002, the UK's Food
Standards Agency (FSA) released "incomplete" data
showing that organic and free-range chickens were twice as
likely as indoor chickens to be contaminated with campylobacter,
the most common cause of food poisoning in Britain.[21]
This was in stark contrast to another report by the FSA, widely
seen as being an anti-organic organization, just a year earlier,
which showed a slightly decreased risk of campylobacter in
organic chicken. Average infection rates in fresh chicken
from supermarkets or butcher shops were reported to be 63
percent, whereas only 60 percent of organic chickens were
infected. Free-range (non-organic) chickens had a 68 percent
infection rate.[22]
A number of other studies have also examined the levels of
campylobacter in organic chicken:
•
A study by the British consumer group Which?
in 2001 found no difference in the incidence of campylobacter
or salmonella between organic and non-organic chickens. Which?
tested 316 samples of raw, fresh chickens and chicken pieces
from five supermarkets - Asda, Safeway, Sainsbury's, Tesco
and Waitrose - and found that organic chicken was equally
likely to be contaminated as standard chicken. Overall, salmonella
and campylobacter were found in 16 percent of chickens and
chicken pieces.[23]
•
A Danish study found that organic broiler chickens
were almost three times as likely as conventional poultry
to be contaminated with campylobacter.[24]
The team at the Danish Veterinary Laboratory in Aarhus found
that all [22]
organic broiler flocks they investigated were infected with
campylobacter. Only one third of 79 conventional broilerhouses
were infected.
•
Researchers at the Southern Illinois University Carbondale
found that meat from chickens raised on organic feed is just
as safe as meat from chickens on a regular diet.[25]
The scientists tested 456 samples from chickens given either
organic or traditional, antibiotic-laced feed. They found
no cases of campylobacter, regardless of feed type. And while
they found nine cases of salmonella, only three of those occurred
among chickens on the organic feed, while six were found in
the traditionally fed chickens. The study only examined free-range
chickens and those raised outside in movable pens, but not
chickens reared in 'factory' farms.
The problem with all of these studies
is that none of them examined which strains of campylobacter
were present or how the contamination occurred. Like E.
coli, campylobacter has several different strains. Most
strains are harmless and live in the intestines of humans
and animals without causing any problems. But others, such
as Campylobacter jejuni, can cause painful stomach
cramps, severe, often bloody, diarrhea, fever and vomiting.
The main source of campylobacter infections is undercooked
poultry, although it can also be caused by red meat, unpasteurised
milk and untreated water. The bacteria do not survive cooking,
but can contaminate other food items if contaminated chickens
are unhygienically handled in the kitchen.
Like the almost-scandal over organic
vegetables containing friendly E. coli, it may be that
organic chickens contain only harmless strains of campylobacter.
Measuring the level of all types of campylobacter as a group
reveals nothing about the safety of any type of chicken. In
fact, at least one scientific study has demonstrated that
chickens which contain large numbers of harmless strains of
campylobacter are much better able to withstand infection
from pathogenic strains.[26]
The five studies above used chickens
from an abattoir, supermarkets, butcher shops and a processing
plant - none of the scientists visited an organic farm. This
is also significant, as most birds are contaminated at the
processing factories where they are slaughtered
[26]
or during transport and holding
[27].
Campylobacter is carried in feces, and chickens tend to defecate
during transport. Birds waiting to be killed are stacked up
in crates with holes in them. Droppings from chickens at the
top of the stack can fall down on to those below. After slaughter,
the birds pass through scald tanks which loosen the feathers,
but the water is generally only changed once a day, and after
a few hours is often a brown soup. The biggest problem comes
at the plucking stage, though. Plucking machines exert pressure
on the dead birds which can squeeze feces out on to equipment.
It takes just 10 to 50 bacteria to pass on the infection,
and feces can contain a billion bacteria per gram, so just
one bird colonized with campylobacter can infect many others.
The vast majority of organic chickens are slaughtered in the
same plants as intensively-reared birds, giving huge potential
for cross-contamination.
It is essential to determine whether
organic chickens are more likely to be contaminated with the
strains of campylobacter which can cause food poisoning, and
these studies need to be undertaken on the farm, before organic
birds come into contact with intensively-reared ones.
Such a study has not been done, but the Soil Association reports
that chickens on one of Britain's largest organic poultry
farms are tested every month by an independent organization
for harmful strains of campylobacter, and to date all results
have been negative.[26]
Mycotoxins
Mycotoxins are toxic by-products
of Aspergillus molds that can grow on a wide variety
of foods and animal feed. When eaten by dairy cattle, some
of these toxins can be metabolized and their metabolites transferred
into milk. Aflatoxins are the most toxic of these compounds
and can induce liver cancer in humans at very low concentrations
if ingested over a long time.
Although fungicides are not allowed in organic farming, many
studies have shown that organic farming does not increase
the risk of mycotoxin contamination.[28]
In fact, three studies have found that aflatoxin M1 levels
in organic milk are lower than in conventional milk.[29],
[30]
A study by the FSA showed that whereas 3 percent of conventionally-produced
milk samples contained aflatoxin M1, no samples of organic
milk were contaminated.[30]
As organically raised livestock are
fed greater proportions of hay, grass and silage, rather than
corn, there is reduced opportunity for mycotoxin-contaminated
feed to lead to contaminated milk. Good practices in animal
feeding also mean that ingredients are checked to ensure quality
standards are maintained and that feed is stored in such a
way as to avoid contamination.
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