Question of the Week: Do Hormones
and Antibiotics Cause Health Problems in Humans?
I often receive questions about
the therapeutic feeding of antibiotics to calves with pneumonia as well as
the implanting of steers to improve growth rate. The following information
is provided to help increase the understanding of these two issues.
Myth: The use of antibiotics
and hormone growth implants in livestock production is causing hazardous
residues in beef and contributing to the development of health problems in
No residues from feeding
antibiotics are found in beef, and there is no valid scientific evidence
that antibiotic use in cattle causes illness resulting from the
development of antibiotic-resistant bacteria.
Scientific authorities agree
that use of hormone implants results in the efficient production of beef
that is safe.
Background: Some say that
low-level, continuous feeding of penicillin and tetracyclines to livestock
and poultry for growth promotion may result in development of antibiotic
resistant bacteria and thus contribute to human illness. The National
Academy of Sciences says it has never found data directly implicating
subtherapeutic use of feed microbials as a risk factor in human illness.
Penicillin is not fed to cattle. For several years, there has been little
subtherapeutic feeding of tetracyclines to cattle, even though such use
continues to be approved as safe. There is no valid scientific evidence that
feeding antibiotics to beef cattle causes human health problems. A recent
report by USDA's Food Safety and Inspection Service showed no antibiotic
residue problems with beef cattle.
Whether or not antibiotics are used in animals, resistant organisms will
exist. But all are sensitive to heat, and proper cooking will kill all
disease-causing bacteria that may be found in beef products.
Hormones are naturally present in infinitesimal amounts in all meat, whether
from implanted animals or not. The amount of estrogen in plant-source foods
is larger than in meat. The human body produces hormones in quantities much
greater than would ever be consumed by eating beef or other foods. Hormones
in beef from implanted steers have no physiological significance for humans
whatsoever. The estrogen level in a 3-oz. serving of beef from an implanted
steer is 1.85 nanograms (a nanogram is a billionth of a gram); the level in
size portion of beef from a non-implanted steer is 1.3 nanograms. By
comparison, a non-pregnant woman produces 480,000 nanograms of estrogen
Hormone implants also increase the efficiency of beef production, thus
alleviating energy, feed usage and environmental impacts, and improve
overall quality and healthfulness of beef by reducing the amount of fat.
The increased efficiency implants offer saves U.S. families hundreds of
dollars each year by lowering the cost of retail beef by 20 cents to 30
cents per pound [IVD50 - 49].
Cattle producers continue to be actively involved in assuring that beef
products are safe and wholesome for consumers. Forty-one states have
industry-initiated beef quality assurance programs that educate producers on
the production of safe and healthful beef products and prevention of
hazardous residues. Participating states account for 98% of the nation's
feedlot cattle and 95% of the country's breeding cows. [BB, 3.5 - 50].
Antibiotics for Animals: The
Antibiotic Resistance Issue, Council for Agricultural Science and
Chemicals in the Meat Supply --
a Review, F.M. Byers, Texas A&M University, 1990.
Expert Committee on Additives, Food and Agricultural Organization/World
Health Organization, 1987.
Food News for Consumers, Food
Safety and Inspection Service, Winter 1990. 49 - Food Safety in the Beef
Cattle Industry, Harlan D. Ritchie, Michigan State University,
proceedings, The LaCosta Conference on "Cattle on the Land:
Environmental Implications of Beef Production, 1990.
Report on Regulatory Program for
Drug and Pesticide Residues in Meat and Poultry, 1989, Richard L.
Carnevale, Food Safety and Inspection Service, 1990.
Report on Use of Hormonal
Substances in Animals, Inter-American Institute for Cooperation on
Subtherapeutic Use of
Antibiotics in Fed Animals Reviewed, Food & Drug Administration, 1989.
of this article:
There is no valid scientific
evidence that feeding antibiotics to beef cattle causes human health
Understanding the Beef Consumer - January,