Contaminants In Milk Fat

It is not necessarily true of chemicals in general or antibiotics in general. It depends on the solubility of the specific chemical. Most antibiotics, as far as I know, are not stored in the body but are excreted. They may or may not be associated with milk fat, depending on their structure. Toxic metals are usually sequestered in intracellular structures, not in fat cells specifically. I have heard that some toxic chemicals of the sort that accumulate are stored with fat: I can't cite a scientific reference though: presumably these chemicals are fat-soluble or structured in such a way as to cluster with natural fats (isoprenoid) or bond with them (I think DDT is one example of this type of sequestration).

To find out what you want to know, try using some of these search terms:

'sequestration" = a biological term for storage of toxins in animals or plants.

'lipid-soluble' or 'isoprenoid' with name of antibiotic or chemical will tell you if it's likely to be stored with fat or associated with fat in milk (where non-accumulating drugs might be present in the liquid because they are constantly dosed rather than stored over time) Chemicals that are fat-like and behave like fat are likely to be removed in a de-fatting process.

PubMed is a good free database to search for this: Current Contents is even better if you have access (not free). Try googling "antibiotic lipid sequestration" and you'll probably get some scientific papers. good luck.

I'm not sure if antibiotics will concentrate in milk solids but it is definitely transfered to them.

I spent many years in the cheese business. All incoming bulk milk transports into a cheese plant, at least in Ontario Canada, come with bulk tank samples. These samples are screened for penicillin and other forms of antibiotics.

The reason for the screens... having milk in the system from just one antibiotic dosed animal can ruin an entire transport truck full of milk and any milk that the antibiotic laced milk comes into contact with. The antibiotic can screw up the cheese making process completely as the antibiotics in the milk survive the pasteurization process and can kill the bacterial culture used to make cheese based both on rod and coccus cultures.

Several silos (500,000 + gallons per silo) of whole milk had to be scrapped due to this issue during my time at that plant. In fact, several truckers lost their milk transport licenses due to their knowingly transporting antibiotic laced milk to a culture using processing facility.