I found several rubber molding manufacturers online that have info about ordering injection molded pieces in FDA food grade silicone (and also medical grade). They state that it can come in a variety of colors including white. My husband just bought some high temp resistant spatulas yesterday that are made of silicone, and they are opaque white. Maybe you said before, but where did you get the information that food grade silicone could only be translucent? I tried looking, but couldn't find that information.
Someone asked me that before (forget who) and like I told him, when I was looking for
medical/food grade silicone tubing I spent a few nights reading through literally dozens and dozens of websites... some silicone manufacturers, FDA pdf's, etc.... this was a month ago so I cannot tell you now but it wasn't one website. It was the distillation of a lot of information from various professional, industrial sites (not Wiki or the like). The understanding I came away with was that rubber and silicone that meet different classifications are color-coded per FDA standards to make them visually identifiable, particularly medical/food grade materials. Different grades meet different FDA specs e.g. "Class IV" or the like. (For example even within medical grade silicone there are three types... one for external use, one for temporary implants and one for permanent implants, each meeting a different FDA classification.)
In the midst of this I also learned that black rubber washers, for instance, made for a faucet are rated EPDM, which is a lesser rating than food grade, because they are only supposed to handle water... not chemicals like we have in food substances. Within EPDM there are many classifications, but all are black. Food grade rubber orings are colored orange per FDA standards... a higher classification than EPDM. (And if you notice some tank vendors that let you pick your tank parts often offer black or orange orings... and they specifically state the black rings are EPDM... always better to go with FDA-orange between those two, but silicone is even better.) And the food grade silicone orings are.... yes, you guessed it. Clearish cloudy white, like the orings in the PT2, both on the head and in the base and top gutters.
I was not looking to special order silicone from a manufacturer and I do not know the laws for asking for a special order of medical grade silicone to be colored in some fashion for the specific purposes of a company.
I was looking for info on readily available o-rings, washers, and tubing from the local hardware store, grocery store, etc. and how to identify medical/food grade silicone over other grades.
So that's the tail I was chasing, and I then found the silicone tubing for beer making.... medical/food grade, rated to 500F and clearish cloudy white. It met the criteria of the FDA spec I was looking for.
I am not a chemist and my understanding is limited to only what I read that night. But
because of what I read that night, unless the makers of these grommets specifically state they are made from food grade silicone and not just "silicone" I have no reason to believe it is food grade silicone, myself. YMMV!!
Finally, the tube I found is cheaper, I am sure it is the proper grade, and works great for me.
So I'm not very motivated.
Bottom line.... I don't personally believe these grommets are food grade silicone but I could be totally wrong and I admit that readily and without equivocation. And if it were proved they were food grade, I'd think, "huh." And that's all I got.
