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Study finds 99% of all Milk Samples are Free from Drug Residue
May 2, 2015

The recent release of the long-awaited FDA drug residue study has plenty for dairy farmers and the consuming public to cheer about.

“The key messages were very clear and very helpful for the U.S. dairy industry,” said Dr. Jamie Jonker, National Milk Producers Federation (NMPF) vice president of sustainability and scientific affairs, during a special Hoard’s Dairyman webinar on April 20. “More than 99 percent of samples were free from drug residues of concern, underscoring the safety of the U.S. milk supply. This is a great story from FDA.”

The FDA also reported it found evidence that the nation’s milk supply safety system is effective in keeping the milk supply safe, he added during the presentation co-hosted by Hoard’s Dairyman and University of Illinois and sponsored by Zoetis.

The in-depth study, initiated in 2012 with results finally released in March of 2015, holds implications for dairy producers, including the possibility of more testing in the future and more rigorous testing of milk.

“This is a developing process,” Jonker said.

There are two types of residue levels the dairy industry is subject to at the farm level. One is a “tolerance,” under which a drug may have a very specific residue level or tolerance, such as 10 parts per billion. When there is no tolerance that is specifically listed, it means the tolerance Is zero.

“In practice, what that means is any detectable amount of that drug in milk would be illegal,” Jonker said. “I think that’s important as we consider that testing technology has gotten more sensitive over the years.”

The other type of regulatory level that the dairy industry is subject to is a “safe” level, established by the FDA Center for Food Safety and Nutrition. A number of drugs, including penicillin, are considered safe under a certain level.

Per the Grade A Pasteurize Milk Ordinance, all bulk milk pickup tanker loads, regardless of final use, are screened for beta-lactam drugs.

“That means every tanker in the U.S. is tested for beta-lactams prior to that milk going into the processing system,” Jonker said, noting other tests are also taking place and can be ordered, if deemed necessary.

The beta-lactam testing program paints a very positive picture of the dairy industry. The national milk drug residue database shows an exciting trend line of reduction from well over 0.1 percent of tankers testing positive in 1995 all the way down to 0.014 percent last year.

“That’s approximately one out of every 7,143 tanker loads of milk,” Jonker noted. “So we’ve had a very great success story there with beta-lactam residues in our milk supply.”

The pasteurized milk ordinance also requires testing of pasteurized Grade A milk products prior to marketing. If a beta-lactam residue is detected, that product cannot be marketed. Over the past three years for which data is available, over 130,000 tests were conducted with no beta-lactam residues found.

“Again, we are given confirmation that, on the milk side, we’re doing a very excellent job,” Jonker said.

Different story for culls

However, Jonker pointed out, a 2010 USDA report reviewing the Food Safety Inspection Service, which has veterinarians in all federally inspected slaughter plants, determined there are more issues with residues relating to dairy cows and bob veal than in other classes of cattle.

“In fact, dairy cows and bob veal amount for somewhere between 80 and 90 percent of all tissue residues that the FSIS finds within an individual year, counting all cattle, all swine and all poultry classes,” Jonker said.

The FDA’s Center for Veterinary Medicine’s investigations of dairy cull cows found the top reasons for tissue residue violations are poor identification of cattle leading to inadvertent shipping; treatments not recorded as a written record, so the animal was shipped before proper withdrawal times were met; and not following label directions or veterinarian recommendations.

The latter two reasons point to extra label drug use. Federal law allows veterinarians to prescribe certain drugs in a manner different than the label and requires they provide the withdrawal period for milk and meat.

If the producer does anything different from the label, such as giving the drug at a higher dose, for a longer period of time or in a different manner, that’s extra-label drug use and actually requires a veterinarian’s prescription, Jonker said.

Importantly, when the FDA investigation of a cull cow tissue violation questioned whether the producer had a valid veterinarian/client relationship, the answer was “no” in 70 percent of the cases.

“I think what we see here is potentially an area where the lack of a veterinarian working with the producer to make informed decisions could result in a tissue residue occurring,” Jonker observed.

Study to determine linkage

In 2012, the FDA launched a residue study, hypothesizing that the same practices associated with tissue residues in culled dairy cattle may also result in drug residues in milk.

With the voluntary cooperation of the dairy industry, the FDA collected 1,912 samples. Of that number, 953 were from dairy farms with cull cow tissue residue violations between 2006 and 2009, and 959 were random samples from other dairy farms. Each sample was analyzed for 31 different drugs, mostly antibiotics.

The FDA survey found and reported that 99.3 percent of the samples were negative for drug residues and 16 residues were found in 15 of the 1,912 milk samples.

The FDA found no statistical difference between the two groups, meaning the study’s hypothesis that the same practices associated with tissue residue in culled dairy cattle might also result in drug residues in milk was not supported by the results.

“The answer is no,” Jonker reported.

The FDA believes the finding of just a few of the samples collected reflect a snapshot in time from a limited number of individual dairy farms and do not pose a health risk to consumers, he added.


The FDA’s response to the released report provides some insight into future implications for dairy producers.

“There are key items in the report that give an idea of what’s going to happen in the future in relation to both milk and dairy cull cow tissue residue violations,” Jonkers said.

For one, the FDA will work closely with state regulators to consider modifying testing to include collecting samples as necessary from milk tanks on farms when investigating illegal drug residues in tissues involving culled dairy cows.

This means that in the future, Jonker said, the FDA Center for Veterinary Medicine may be taking milk samples from bulk tanks during investigations of dairy cull cow tissue violations.

“If they take a sample, they will subject it to very rigorous testing for all drugs listed in this webinar and perhaps more,” Jonker said, noting the FDA is continuing to refine its methodologies for looking at residues in milk and in other products.

“So if you have, as a dairy producer, a cull dairy cow with a tissue residue violation, there is a reasonable probability that FDA in the future, coming on to your farm, could take a milk tank sample as well,” Jonker added.

FDA also said it will utilize the survey data to help develop risk ranking for drug residues in milk that will assist the National Conference on Interstate Milk Shipments in including testing for more diverse drug classes in milk as necessary.

“This information is being used with a broader set of information to determine if there is a need for additional testing for drugs in milk,” Jonker explained.

The final point gleaned from the FDA’s response is that it will continue to work collaboratively with state regulatory agency partners in the dairy industry to strengthen the NCIMS drug residue testing program for Grade A milk and to educate dairy producers on best practices.

That means the survey information will be used to determine if there needs to be changes to the current testing program, which requires all tanker trucks to be tested for beta-lactam drugs.

“So, potentially, other classes of drugs could be added,” Jonker said.

The NCIMS is the oversight body that puts together requirements for the Grade A pasteurized milk program. It meets every other year to consider changes to the program, with the next session scheduled for April 24-29 in Portland, Oregon.

“At this conference, the report findings will be used by FDA to consider changes in the milk residue testing system,” Jonker said. “There is a variety of proposals under consideration for changing how and what we test for dinner about tanks in our bulk tanks and our bulk tanker trucks. Stay tuned.”

Source:Wisconsin State Farmer


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