Organic or Non-Organic Milk, What's the Difference? - Chromatography Investigates

Milk is a naturally produced substance that mammals use to feed their young. There are many arguments for and against the use of dairy products, including milk, in our diets. Ethical concerns about the treatment of cows and economic concerns regarding how farmers are treated by milk suppliers. But, whatever concerns people have regarding animal welfare and the treatment of farmers - most nutritionists agree that dairy products including milk are beneficial for our health.

But is all milk the same? Well it seems as if this might not be the case. A recent study published in the journal Public Health Nutrition has considered the levels of production related contaminants including pesticides, antibiotics and hormones in organic and non-organic milk produced in the US. And it seems that non-organic milk might contain compounds not found in organic milk.

Buffalo, goat or sheep - what’s your favourite

Milk is quite a simply product really - naturally produced in the mammary glands of mammals to feed their young until they are old enough to hunt and feed themselves. But humans took this a step further and decided to try and use milk from other animals to supplement our diet. Using a natural product to help provide nutrition throughout our lives.

We can get milk from many different animals - sheep, goats reindeer and buffalo are all farmed in various parts of the world to produce milk. But it is cow’s milk that is the most commonly used milk. And we don’t just use milk - cheese, butter and ice cream can all provide the health benefits associated with milk. But while our ancestors undoubtedly drank organic milk - as up until the last few decades that is all there was - modern milk might well contain some additional additives courtesy of modern farming methods.

What’s in the milk?

The recent study was carried out in the US and considered samples collected across the US. They compared organic and conventional milk from different brands - both whole milk and reduced fat milk. They checked pesticide levels, antibiotic levels and hormone levels in all milk samples using both gas and liquid chromatography in conjunction with mass spectrometry. The following article discusses how to improve sensitivity in chromatographic analysis, Using Narrow Bore Columns to Enhance Sensitivity for LC-UV and LC-MS Analyses.

The team report that current use antibiotics and pesticides were not detected in the organic milk samples but were found in conventionally produced milk samples. In fact, they found that several samples had levels that exceeded federal limits. They also report that there is evidence of synthetic growth hormone being used in the cows that produced conventional milk. Whether these finding impact the health of consumers remains to be seen.