Symbol for plastic to indicate that it is free of animal fat

The majority of plastics packaging products today are made with additives which could contain animal fat, says Premier Group International (PGI). Animal-derived additives, called stearates, are used with packaging for food, beverages, and medicines, the company said.

Plastics which carry PGI's officially registered ERC (ethically and religiously compliant) certification are guaranteed free of animal stearates or byproducts, says the company. There are standards to certify food ingredients, but not for the plastics used to package those foods, notes the company website. 

There are indications that additives to plastics can leach out into the surrounding environment*. Additives in plastic food packaging could thus get into the food it is in contact with. 

A 2010 study by Dr Dennis Jenke, currently a Baxter Distinguished Scientist in the Technology Resources Division of the Baxter Healthcare Corporation, studied the leaching behaviour of stearic acid, calcium stearate, and zinc stearate and four polymeric (plastic) materials containing these compounds by putting them in contact with liquids of different acidity and alkalinity.

Dr Jenke found that more acidic liquids were able to extract the chemicals for materials that only contained stearic acid, calcium stearate or zinc stearate. Neutral liquids did not cause much reaction, while alkaline liquids extracted stearates from the materials "to a very limited extent". It was not clear what would happen if the material contained stearates as well as other substances, as in the case of today's plastics, and the research did not cover plastic that had been in contact with oil or liquids of different temperatures.

PGI has also launched its own plastic bowls and storage containers with the ERC symbol. According to the PGI website, its subsidiary Premier Classic Products manufactures the only plastic containers that are certified kosher/halal compliant and are made exclusively with ingredients that are acceptable to these religions.

*A 2009 study on Harvard College students found that those who drank cold drinks out of polycarbonate bottles (the clear, hard plastic type sold for sports and used for baby bottles and which can be used for hot drinks) had higher concentrations of bisphenol-A (BPA) in their urine than students who did not. And in 2011, a researcher from the University of Gothenburg soaked newly-purchased plastic items in deionised water for one to three days, then introduced water fleas to the water. One-third of 83 randomly chosen plastic products and synthetic chemicals that were tested released substances that were acutely toxic to the water fleas. According to the report of the research, the toxicity was mainly caused by fat-soluble organic substances.