The Study

Sourcing the Menu: Dairy – Milk, Cheese, Yogurt, Butter

NOTE: This is an edited version of portions of Appendices 2 & 3 of the “Revised Stealth Syndromes Study Protocol as approved by the University of California San Francisco Medical School Committee on Human Research.

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Standards and Sourcing (From Appendix 2)


Same water, feed, and pasturing requirements as beef, lamb, and goat.

Udder and teat cleaning and treatments for animal welfare and human hygiene must be examined for plastic exposures and contamination minimized.

Milking must be done preferably by hand or using milk machines certified as BPA and phthalate-free. Nitrile gloves to be used. All collected milk must be in stainless steel vessels. Filtering stages cannot use polymer filters. Separation, homogenization (if any) and pasteurization must be plastic free. Glass containers must be used for bottling of milk.

Cream gathered during the separation process will either be used for cheese or discarded to minimize lipophilic contaminate concentration.

Cheese will be made using milk prepared as described above. Preference will be given to low- or moderate-butterfat cheeses.

The cheese process will use stainless steel in the initial heating processes. Curds will be gathered and drained in stainless-steel wire baskets. The whey will be discarded.

Drained curds will be pressed in stainless steel molds. Finished cheese will be packed in aluminum foil then placed in Ziploc-type airtight containers.

Note: Ziploc claims to be BPA free but has not addressed phthalates. It is also unknown whether “BPA free” means a switch to a Bisphenol analog such as BPS.

Rationale (From Appendix 3)

Dairy: Milk & Cheese

The contamination of the dairy chain starts with what the female mammal — aka “cow” — consumes. This is most often a bovine cow in America, but globally includes goats, sheep and other mammals. (see “Meat the enemy”)

The milk from cows — like its flesh and that of its male counterparts — can be contaminated with environmental chemicals from its food and water.

But the milk produced will be further contaminated by many additional processes before milk, cheese, yogurt and the whey for dietary supplements reaches a human consumer.

The introduction of plastic chemicals into the dairy food chain begins with the milking process and continues to increase at each step before reaching the consumer.

Milking machines

Other than the rare artisan-produced cheese, the hand-milking of cows, goats and other livestock has mostly vanished. Milking machines make the first step of production more cost effective, time-efficient, and sanitary — all benefits to the consumer.

Before milking begins, the udder and teats undergo a number of hygiene steps that include cleaning with anti-bacterial solutions (Hygiene in milk production).

This helps insure the cleanliness of the milk and starts a process to extend the length of time before milk can sour. This also helps prevent injuries to the cow, including mastitis, a serious inflammation of the udder and mammary gland.

Another anti-bacterial cleaning occurs after milking. All of the cleaning and irritation from the milking machine results in the application of salves.

No research can be found so far on whether antibiotics, salves and cleaning agents may contaminate the collected milk.

It’s also notable that plastic gloves worn by handlers through the milking process can result in phthalate transfer to the teat. This extent of this transfer is unknown.

In addition, the phthalates and other EDCs in the gloves can leach out and be absorbed through the skin of the wearer. The leaching and transfer is encouraged by people who use hand creams.

Plastic contamination and the milking machine

Milking machines use a pulsating vacuum to draw raw milk from the udder.

The teatcup that attaches to each teat is lined with a flexible plastic (phthalate soft) that alternately compresses and relaxes as the vacuum pump operates.

The milk is drawn into a one-way plastic chamber (known as “the claw”) which allows the milk to be drawn off and transferred into a collection tank that is sometimes plastic, sometimes stainless steel. From the collection tank, milk flows to a bulk tank, frequently via plastic piping or tubing. (How the milking system works)

From the bulk tank at the dairy, milk is transferred via plastic hoses to a tanker truck which reverses the process through plastic hoses to larger tanks at the creamery. All of the processing involves plastic hoses, pipes, fixtures, pumps, valves, vats, vessels and other equipment that often contain or are made of plastic.

At the creamery, plastic hoses dominate the processes of separating cream from the whole milk. The skimmed milk and cream are usually pasteurized separately.

Some cream is returned to the skimmed milk to create a range of butterfat levels, some is made into butter. Cheese can be made from milk at a variety of stages in this process.


Significantly, BPA, phthalates and many other harmful environmental chemicals are “lipophilic” — they are easily dissolved in fats.

This means that the cream separation process creates a high-fat environment that encourages leaching of these environmental chemicals into dairy products.

Cheese & Whey

Cheese made from whole milk contains more fat. More fat offers contamination opportunities for lipophilic chemicals like BPA and phthalates.

The cheesemaking process can use plastics at various points, but most likely as utensils, filtering materials, molds for curds and the process for draining off whey. Further contamination can occur in the processing that cuts large blocks then wraps individual blocks, wheels, and other large shapes. Sliced and grated cheeses expose cheese to contamination as well as the plastic pouches and bags they are packed in.

Most organic cheeses use plastic in their final packaging. The most highly contaminated will be blocks which have been shrink-wrapped. This is because the film is warm/hot when it comes into contact with the cheese. The heat encourages migration of contamination from the plastic into the cheese.

Whey is a mostly water-loving substance left over from the cheesemaking process. However, studies have shown that many organic contaminates can be bound to the milk proteins.