Colloidal silver actually plates out on glass, not plastic, depending on the type of plastic. Our cobalt blue bottles are a high quality, pharmaceutical grade PET plastic.
Not all plastics are created equal! One researcher brewed a batch of CS, measured it with a spectrophotometer for accurate ppm level, and then stored this batch in several types of plastics for an extended period of time. He then measured the CS from each container to see if the ppm had increased (which would indicate that the plastic was dissolving, or "bleeding" into the CS).
He said the milky-white plastic such as milk frequently is sold in (as well as most 1-gallon bottles of various types of spring and distilled water) was quite guilty of this bleeding-phenomena. The plastics that changed the ppm level not at all (10.7 ppm was still 10.7 ppm, even after extended storage) were the hard, shiny plastic such as soda pop comes in which is PET plastic.
Polyethylene Terephthalate(PET), is a High Density Polyethylene(HDPE), are FDA approved and have been proven to be safe.
PET does not contain plasticizers. “Plasticizers” are added to make plastics soft or flexible. For example, semi-rigid plastic like polyvinyl chloride (PVC or vinyl) typically contains about 10% by weight of plasticizers and is very soft, polyvinyl chloride tubing may contain as much as 80%. Under the right circumstances plasticizers can migrate out of certain plastics.
The International Life Sciences Institute (ILSI) – a nonprofit organization dedicated to advancing the scientific understanding of issues related to nutrition, food safety, toxicology, risk assessment and the environment – has comprehensively reviewed the scientific and technological aspects of PET.
In a report on PET for food packaging applications issued in July of 2000, ILSI summarizes the large body of test data that demonstrates the safety of PET resins and compounds for food and beverage containers:
“PET plastic itself is biologically inert if ingested, is dermally safe during handling and is not a hazard if inhaled. No evidence of toxicity has been detected in feeding studies using animals. Negative results from Ames tests and studies into unscheduled DNA synthesis indicate that PET is not genotoxic. Similar studies conducted with monomers and typical PET intermediates also indicate that these materials are essentially nontoxic and pose no threats to human health… It is important to stress that the chemistry of compounds that are used to manufacture PET shows no evidence of oestrogenic activity. There is a significant body of evidence that demonstrates that the use of PET is not a concern and is perfectly safe in this respect.”