By MICHELE F. MIHALJEVICH

Indiana Correspondent

ATLANTA, Ga. — An Emory University study that found current-use pesticides and antibiotics in samples of conventional milk – while finding none in organic milk – is “highly questionable,” say several dairy-related organizations.

The study, published last month in the Public Health Nutrition journal, said the contaminants were “prevalent in conventionally produced milk samples, with multiple samples exceeding federal limits.” It also said higher levels of bovine growth hormone (bGH) and bGH-associated insulin-like growth factor (IGF-1) suggest the presence of synthetic growth hormone in conventional milk.

The study was done in collaboration with The Organic Center.

Milk is one of the safest foods consumers can buy, noted a joint statement from the National Dairy Council, the International Dairy Foods Assoc., and the National Milk Producers Federation.

“Regarding this new study, it is very important to note that information about the methodology used is so scant that serious flaws are likely to exist,” the organizations said. “Many of the key results raise red flags and leave more questions than answers, including a sample size that is not statistically valid, a four-year lag between data collection and published analysis, and results that are so far out of line with federal government data that they seem implausible.

“Given these facts, combined with the historical testing data using FDA (U.S. Food and Drug Administration)-approved methodology that clearly demonstrates the occurrence of residues for several of the antibiotics in question is extremely rare, the data underlying this recent study must be considered highly questionable and not a true reflection of the U.S. milk supply.”

The study’s authors said consumption of cow’s milk has decreased in the United States while demand for more costly organic milk has increased. This suggests consumer concern about exposure to production-related contaminants may be contributing to this decline, they noted.

With the study, the authors sought to determine if contaminant levels differ by the production method used. The authors tested half-gallon containers of organic and conventional milk from across the country in 2015.

Pesticide, antibiotic, and hormone residues were compared against established federal limits and by production method. The study found residue levels exceeded federal limits for amoxicillin, sulfamethazine, and sulfathiazole in some conventional milk samples.

Attempts by Farm World to reach the authors for comment were unsuccessful.

For milk to be considered organic, producers must adhere to specific production practices mandated by the USDA, said Maurice Eastridge, professor of animal sciences for The Ohio State University. For example, cows must spend a percentage of their time in pastures and they must consume forages and concentrates that are grown organically.

No pesticides or herbicides may be used on forages or on soybean or corn used for meal. “There are also strict guidelines on what can be used to treat sick animals,” he explained. “No antibiotics are allowed.

“If a cow becomes sick enough that treatment with antibiotics is necessary, it must be removed from the farm and go to a conventional dairy operation.”

The study’s connection with the organic trade group does raise questions, Eastridge added.

“The impression is, they’re on a witch hunt in order to promote organic foods. It’s human nature that we might have that reaction. But we have to look at the study – was it well designed, were enough samples taken, did they reach the proper conclusions?”

The authors examined samples from across the U.S., he noted. The total number of samples was fairly limited, Eastridge said, considering the thousands of samples that are continuously monitored nationwide.

Milk is tested multiple times during the production and processing steps, he said. No antibiotics, pesticides, or synthetic hormones in milk are allowed. Low levels of some hormones will be present because they’re naturally occurring in cows and can be secreted into the milk, Eastridge pointed out. Naturally occurring hormones also occur in some plant sources, especially food from legumes.

It’s possible some consumers could turn away from dairy completely after seeing the study’s results, he said. “They may think they shouldn’t have milk. There are studies showing some consumers trust non-governmental organizations more than the government. They may think they should believe this rather than the FDA.

“However, consumers need to take into account the results of many studies rather than a single one and the totality of effort in place to provide for safe and wholesome food,” he said.

The Organic Center said the researchers developed testing methods more sensitive than past analyses and measured levels of chemicals previously unreported.

“These new methods give us a true picture of the presence or absence of residues in milk,” said Jessica Shade, director of science programs for the Center. “The methodology was proven and solid and put systems in place to control for results that would inaccurately indicate the presence or absence of the residues. The statistical significance was so clear and decisive that it gives us confidence that what we found in the study would also be the results of a larger sampling.

“Not all milk is created equal, as this study demonstrates. This study finds that the presence of antibiotics and pesticides in conventional milk is much more prevalent and pervasive that previously thought – and that organic milk doesn’t contain any of these contaminants.”