U. S. Food and Drug Administration
Center for Food Safety and Applied Nutrition
FDA Prime Connection

Cornell University - bST Fact Sheet
 
 
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Donna L. Scott                                                8 Stocking Hall
Department of Food Science                                 Cornell University
Food Safety Extension Group
607-255-7922                                   E-mail: dscott@cce.cornell.edu
Fax: 607-254-4868
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bST Fact Sheet written by Professor David Barbano of this department. It is
longer than the typical fact sheet, but we felt that thorough information about
this topic should be available to those who want it.
 
 
Are milk and meat from bST-supplemented cows safe?
 
YES!  Extensive  studies of the safety of bST have been conducted world-wide and
reviewed by the  Food and Drug Administration (FDA). The FDA concluded that both
milk and meat are safe.  A separate review of the data has been conducted by the
National Institute of Health, the World Health Organization, the Office of the
Inspector General of the Department of Health and Human Services, and reviews by
the Journal of the American Medical Association, Pediatrics, and the Journal of
the American Dietetic Association all independently have arrived at the same
conclusion, milk and meat from bST supplemented cows are safe. In addition,
regulatory agencies from countries around the world have reached the same
conclusion, milk and meat from bST supplemented cows are safe. In addition,
regulatory agencies from countries around the world have reached the same
conclusion.
 
What is bST?
 
bST is an abbreviation for bovine somatotropin or what is also called bovine
growth hormone.  The term rbST has been used to refer to bST that is produced
using fermentation technology and injected into dairy cows to increase
efficiency of milk production.
 
Is bST a hormone?
 
Yes.  However, there are two types of hormones: steroids and proteins.  bST is
a protein hormone.  Protein hormones have no activity when taken by mouth, while
steroid hormones do have activity. For example, insulin is a protein hormone.
Insulin has no activity if taken orally.  Therefore, a diabetic has to have
injections of insulin.  Like insulin, the protein hormone bST has no activity
when taken by mouth.  In contrast, hormones used in birth control pills are
steroids and therefore are effective when taken by mouth.  Again, bST has no
effect when taken by mouth.
 
Furthermore, studies were conducted in the 1950's to determine  if children
suffering from dwarfism could be given direct injections of high levels of bST
to stimulate growth.  The conclusion of the study was that somatotropin from
cows is  not active in humans even if injected.  Why?  The structure of human
somatotropin is so different from bovine somatotropin, that  injections of high
levels of bovine somatotropin into children  have no influence on growth and
development.
 
How does bST work?
 
The pituitary gland of the dairy cow normally produces bST.  bST is one of a
group of hormones produced naturally in the cow that controls milk production.
Supplemental rbST can be injected into a dairy cow.  Both sources of bST  (that
produced by the cow herself and supplemental) are carried to the liver  of the
cow via the blood stream.  bST in the liver stimulates this organ to produce
insulin-like growth factor (IGF-1), another protein hormone that plays an
important role in helping regulate the conversion of dietary nutrients into
milk.
 
Supplemental bST helps increase the efficiency of conversion of feed to milk in
the cow's body.  It has been shown that to support  increased milk production,
a cow supplemented with rbST automatically consumes more feed.  The amount of
nutrients required  for the cow's body maintenance remain unchanged, therefore,
the cow's increased nutrient intake is used primarily for milk production.  bST
is found in  trace amounts in  milk from all cows, unsupplemented and
supplemented.
 
Milk from cows given supplemental bST contains no more bST than milk from cows
not given the supplement.
 
Is there any difference between milk from bST supplemented cows    and
unsupplemented cows?
 
For all practical purposes no.  There are no differences in nutrient content
(i.e., fat, protein, calcium, vitamins, etc.) or sensory characteristics (flavor,
color, etc.).  There is no difference in bST content.
 
The concentration of IGF-1 in milk from supplemented cows is slightly higher than
from unsupplemented cows.  However, the average increase in concentration in milk
is small compared to normal variations in concentration of this compound from
cow-to-cow in milk from unsupplemented animals.  The average increase of  IGF-1
in milk produced by supplemented cows is also small compared  to the variation
in amounts that occur normally  from the beginning to end of the cow's lactation
period.
 
Should I be concerned about the small difference in concentration of IGF-1  in
milk?
 
No.  IGF-1 is normally present in milk. It is a protein hormone and  is digested
just like any other protein in milk, meat, or other    foods that you eat.  IGF-1
is not active when consumed by mouth.   IGF-1 is a normal component in human
milk.  The average amount of  IGF-1 in human milk is higher than that found in
milk from  bST    supplemented cows.  IGF-1 is also present in human saliva and
the  average person consumes IGF-1 from this source each day that is equivalent
to the amount consumed from any source of milk.
 
How much more milk does a bST supplemented cow produce?
 
On average about 10%.  After having a calf, a cow produces milk for  about 300
days. The highest daily  milk production will occur at   about 8 weeks after
calving and then the level of milk production  per day gradually declines during
the rest of the lactation period.  Not all cows give the same amount of milk.
Cows that produce the highest amounts of milk generally have about the same peak
milk    production per day as lower producing cows.  However, the rate of
decline in daily production of milk  during the rest of lactation is slower in
these high-producing cows.
 
Administration of supplemental bST is started after the peak of milk production
occurs and causes the cow to maintain a higher level milk production per day
during the period when milk  production is normally declining.  Therefore, a cow
supplemented with bST will not be producing more milk per day than it produced
per day at peak production prior to the start of bST supplements.
 
Won't higher milk production trigger mastitis in cows?
 
The question of animal health has been reviewed extensively by  the FDA and was
the subject of a special FDA Expert Advisory Panel   hearing on March 31, 1993.
The Panel reported that based on      extensive research results, any increase
in mastitis that may result from use of bST is insignificant compared to the
increase in  mastitis that occurs normally for other reasons, such as seasonal
variation, extremes of weather conditions, age of the cow, and stage of
lactation.  The influence of season of the year changes the incidence of mastitis
9 times more that the influence of bST.
 
Doesn't treating mastitis require antibiotics which might find their way into
milk and affect milk safety?
 
No. Federal and state milk  safety and quality assurance programs,  as well as
testing by farmers and processors, ensure the  safety and wholesomeness of milk.
When a farmer treats a cow with an antibiotic, the milk from that cow is
discarded by the farmer for  several days as defined on the label of the
antibiotic.  In many   cases today, a concerned farmer sends a sample of milk
from that cow to the dairy plant to be tested for antibiotics before the milk
from that cow is allowed to go in with the milk to be sold.
 
When milk is picked up at dairy farms, the  truck driver must take a sample  of
milk from the farm bulk tank at every farm before the milk is pumped into the
truck.   When every truck arrives at a milk processing plant, a milk sample is
taken from the milk in the truck and tested for antibiotics.   If the load is
positive,  the truck  is not unloaded.  Another sample is taken and the positive
test is  confirmed.  If the load of milk is positive for antibiotics, then  all
of the individual farm samples that the driver collected are tested to identify
which farm's milk contained the antibiotics.  In  addition, the dairy plant  must
notify the local regulatory agency  that milk is being discarded and they need
to document the manner in which is was discarded.
 
There are very large financial penalties imposed on dairy farmers  that
contaminate a truck load of milk with antibiotics.  Many processing plants have
offered incentives to their farmers to avoid  contamination of tank trucks of
milk with antibiotics.  If a farmer  thinks a mistake has  been made and his/her
milk is contaminated, he/she can call the plant and have a milk sample picked up
and tested.  If the tank of milk is positive and the farmer prevented it from
contaminating  a  full  truck load,  then  some plants have a program to pay the
farmer for one tank of milk during some period of time (for instance, 1
year).
 
What impact will the approval of bST have on the economy and the   environment
in the US?
 
The US Office of Management and Budget recently reported that the  use of bST
will likely have a small but positive impact on the US  economy and environment.
Use of bST will reduce the amount of animal waste per unit of  milk produced and
will reduce the amount of feed required to produce a unit of milk. This will be
an environmental benefit.
 
Will some dairy products be labeled as "from cows not treated with  rbST" and
what does it mean?
 
This type of label will be  allowed by the US FDA. FDA  also requires that all
statements on food product labels must be truthful and not  misleading. The FDA
recommends that the company also put information on the label to inform the
consumer that "no significant difference has been shown between milk derived from
rbST-treated cows and non-rbST-treated cows".  FDA says that this will put the
statement "from cows not treated with rbSTS in proper perspective so it is not
misleading.  The FDA recommends that firms that make such claims establish a plan
and maintain records to substantiate their claims, and make those records
available for  inspection by regulatory agencies responsible to verify the
accuracy of the label claim.
 
Will the commercialization  of bST hurt  the small dairy  farmer?
 
The effective use of bST  has nothing to do with farm size.  Unlike  many new
technologies, there is no up-front  capital costs before a farmer starts using
this technology.  Thus, small farms will have equal access to this technology.
The Office of Technology Assessment  has concluded that "quality of management"
on the dairy  farm, not farm size, will be the major factor affecting the
magnitude of milk production response from  bST.  Better farm managers will
benefit most from bST, regardless of farm size.  Milk price is derived from many
factors including consumer demand,  business costs, and government regulations.
 
Will bST create a large surplus of dairy products?
 
No.  The signal to a dairy farmer that triggers the production of more or less
milk is the difference between the price of milk paid to the dairy farmer and the
cost of producing that milk.  Farmers  will continue to respond to these signals.
The larger the spread between cost of production and price paid to the farmer for
milk, the greater the incentive for dairy farmers to produce more milk.  Prior
to the introduction of bST there have been times of short and surplus milk supply
and times of high and low milk prices.  This will continue with or without bST
use.
 
Use of supplemental bST will provide dairy farmers with a production management
tool to produce the same amount of milk that would have been produced without bST
with fewer cows and at lower cost.  The signal to the dairy farmer to produce
more or less milk will continue to be based on the difference between the price
paid for milk and the cost of milk production.  For the well-managed dairy farm
that adopts bST technology (just like any other technology that improves
efficiency), profitability should be enhanced.
 
Over the period from 1982 to 1992 (when most of the research on bST has taken
place), new technology  and better dairy farm management  without supplemental
bST has increased the annual milk production per cow from 12,306 to 15,423 pounds
per year (25% increase in productivity per cow), while the number of cows has
decreased.
 
Increased production efficiency has kept the rate of increase of dairy product
prices to consumers lower than increases in prices  of other foods.  Thus,
excellent food value for the price, new product offerings (such as low fat
products) developed through dairy product research that meet changing consumer
needs, and promotion of dairy products have increased total sales of milk for
commercial use from 122 billion pounds to 142 billion pounds over the same 10
year period.
 
Should I buy raw milk from a local farmer and pasteurize it at home  to be sure
I don't drink milk from bST supplemented cows?
 
While it is possible to do this, there are several risks involved that a consumer
should be aware of before they begin this practice.  About 2 to 10% of raw milk
contains harmful bacteria (such as, Salmonella, Listeria, Campylobacter, E. coli
0157:H7 and possibly  other pathogens).  These disease causing bacteria are all
killed by  commercial pasteurization.  There is very strict regulatory
inspection, control, and testing of milk processing equipment and personnel to
ensure that commercially pasteurized milk does not contain pathogenic bacteria
and tha  milk is not recontaminated after it is pasteurized. When pasteurization
of milk is done at home, there is always a possibility that the milk will not be
fully pasteurized or that it will be contaminated after pasteurization.
 
In addition, all milk from commercial processing plants is tested for the
presence of antibiotics prior to processing and bottling. If a consumer buys raw
milk directly from a dairy farmer, that consumer has abandoned the dairy
industry's quality and safety assurance system designed to protect them from
antibiotic contaminated milk.  The food safety risks of home pasteurization could
be large compared with the low level of risk that has been enjoyed by consumers
of commercially pasteurized milk.
 
For answers to additional questions, contact Professor David M. Barbano
Department of Food Science Cornell University, (607) 255-5482.
 
                                                                    (06/09/95)