KANSAS CITY — In several recent public appearances, executives with
the American Meat Institute, including president and chief executive
officer J. Patrick Boyle, have stated that the prevalence of E. coli
O157:H7 in beef products is going down, and they’ve used data from the
Food Safety and Inspection Service and the Centers for Disease Control
and Prevention to support the claim. Using test data from the F.S.I.S.,
the A.M.I. has in particular emphasized that from 2000 through 2008, E.
coli prevalence in ground beef dropped 45%, suggesting the beef
industry’s various efforts to control the pathogen have been effective.

Barbara Kowalcyk, director of food safety for the Center for Foodborne
Illness, Research & Prevention in Grove City, Pa., and a doctoral
student in molecular epidemiology and environmental health, said the
A.M.I. is misusing the data to paint a rosy picture for consumers
that’s dishonest. In a strongly worded statement released last month,
in which she called Mr. Boyle’s recent comments about E. coli reduction
in beef “inappropriate and misleading,” Ms. Kowalcyk wrote: “U.S.D.A.’s
E. coli O157:H7 microbiological testing program is strictly regulatory
and was not statistically designed to estimate the prevalence of E.
coli O157:H7 in raw ground beef. Different establishments are sampled
each year. Further, the methods used to select establishments and to
conduct the microbial testing have changed over the years. As a result,
it is inappropriate to make year-to-year comparisons. Several sources,
including U.S.D.A. itself, have noted the limitations of the data
obtained from U.S.D.A.’s Verification Testing Programs.”

don’t think it’s possible to draw any conclusions about the prevalence
of E. coli from these data,” she said. “This is not a small issue, this
is a big one.”

Jim Hodges, executive vice-president of the
A.M.I. and director of the American Meat Institute Foundation, which
supports scientific research, said he doesn’t necessarily dispute Ms.
Kowalcyk’s statements.

“She takes a pure view of how these
numbers are derived,” he said. “Fundamentally, I don’t disagree with
her. But the fact is, everyone uses these numbers to look at trends –
F.S.I.S. does it, C.D.C. does it, everyone does it. If we wanted to be
perfectly accurate, we’d say there has been a significant reduction in
E. coli, but people want to know how much, so we use percentages to
show a trend.

“I guarantee you trends are important to
everyone,” he added. “And that’s all we’re trying to communicate. The
point is trends, not actual numbers.”

Ms. Kowalcyk isn’t buying
it. She said it isn’t accurate to compare selected year-to-year data
from tests that were never intended to point toward a trend. She said
the test data collected in 2008 came from a different group of beef
plants than the test data from eight years earlier. The side-by-side
comparison does show a 45% drop, she admitted, but likens such a
comparison to comparing someone who weighed 300 pounds in 2000 to
someone else who weighed 150 pounds in 2008 and drawing the conclusion
that people in general have experienced a 50% drop in weight.

you want to do a trend analysis, let’s be honest about it,” she said.
“The misuse of statistics is what gives statistics a bad name,” adding
that U.S.D.A.’s own Web site misapplies E. coli test data to prove
trends that don’t exist.