Meat + Poultry - February 2009 - 64

C. DIFF

that more than 40
percent of packaged-meat samples taken from
three Arizona supermarket chains
tested positive for the
pathogen, and some of
these tested positive for
the virulent new strain.
He calls the results "very
surprising." He has detected
C. diff's presence in ground
meats as well as in sausages
made from ground product, such
as fresh pork sausage, chorizo, summer sausage and even liver sausage. He
found the bug in half the ground-beef
samples he tested and in 62 percent of
the brauschweiger. "We haven't looked
at whole-muscle meat yet, but when we
do I suspect we'll find it," he says.
He adds that when he first began investigating C. diff in food a few years
ago, "I thought it was a fool's errand. I
couldn't believe someone hadn't found
it already. I was sure that if it was there,
someone would have found it. But it
seems like no one did look. And when
we finally did, we found it."
Weese's numbers aren't quite so
shocking, but they remain troubling.
His team took C. diff-positive samples
from 18 percent of the ground beef and
ground veal tested, though they did not
find the virulent strain, and the numbers
of cells the team found in the positive
samples was somewhat lower than what
Songer's team found. Harvey's work at
ARS, and previous work by both Songer
and Weese, already found C. diff in dairy
calves and pigs, as noted.
"We know we can find it widely in
the environment," Weese says. "What
we don't know is how it travels from
farms to food. We've got a big gap in
our knowledge so far."
He points out that C. diff, which was
first identified in 1935 (it was originally
named "Bacillus difficile," or "the difficult" microbe), is unique among pathogens in a couple of ways. One, it can
be found among the gut flora of healthy
humans, causing no evident ill effects.
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February 2009

This is why,
when the population of C. diff cells
suddenly expands (no one
knows why), treatment with antibiotics can be so dangerous; with the
other microflora pushed out of the way
by the drugs, C. diff takes over. Another C. diff's attribute that's unique: As a
spore-forming microbe rather than a
cell-former, it can survive typical cooking temperatures - think of it as a kind
of opposite of Listeria monocytogenes,

" C. diff "could be the
next O157 - or it could
be nothing. I suspect
it'll turn out to be
something in between."
which survives refrigeration.
Still, Weese actually takes some comfort, he says, in the high rates of positives that Songer found in the grocery
meats. "In some ways, finding it so commonly downplays the risk. If it's being
found in 40 percent of humans or on
40 percent of meat samples, we know
that 40 percent of the human population isn't getting sick from it."

In search of CCPs
As for meat specifically, Weese isn't ready
to sound alarms. "Meat might be just a
carrier, we don't know. The real problem
might always be spreading from human
to human, with meat just an intermediary.
I don't think the industry should panic at
this point - but we should be concerned."
"I can tell you that it's not coming in
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to nursing homes
on food," adds
Dave Theno.
"It's already
there. In that
environment or
in a hospital, it can always move from person to
person. We're talking about a very
opportunistic bug."
"We know it can cause illness in
baby pigs," says Liz Wagstrom at NPPC.
"But C. diff is not C. diff is not C. diff -
what I mean is, just because it's in livestock doesn't automatically mean meat
is a problem. One reason why it may
be showing up in ground meats is because those products are handled by
more people than other kinds of meat
products." She also points out that both
Weese's and Songer's retail sampling so
far has been regional. C. diff's national
and global distribution in meat and livestock isn't yet mapped. "I think it's something that we need to look at carefully to
see if there's an emerging problem. But
at this point I don't believe C. diff is our
next BSE or O157."
CDC's Limbago, who will be discussing C. diff at a gathering of meat and
animal scientists this coming March,
emphasizes that "there's no epidemiological link" connecting even the "indistinguishable" strains found in livestock and humans. "Animals might be
just some kind of reservoir," she says,
underscoring Weese's point. In agreement with virtually all other C. difficile
researchers and observers, she says it's
just too early to tell what kind of role
meat and livestock play in C. diff's lifecycle and distribution.
Songer is also cautious about sounding alarms, but he pushes the industry to
be proactive. "We can even now probably get ahead of this," he says. "Let's
find the critical control points for this,
and let's take care of them."
Steve Bjerklie is M&P's East Coast correspondent,
based in Franconia, N.H. He has worked as a journalist covering the meat and poultry processing industry
for more than 25 years.
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Meat + Poultry - February 2009

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