is all PP plastic the same/food grade?

[fredthecat]

I've been looking around for items improvisable as cheese draining forms. I found these plastic sink drain food waste catchers. They are not intended to be used for eating food off of. However they say they are PP (polypropylene) #5. If something is labeled as PPs it good safe? Will the coloured plastic be an issue? Here's a photo of one, however the one i am thinking of getting looks higher quality than the pictured one.

[Kern]

As a general rule both polyethylene (PE) and polypropylene (PP) are food safe.  In their natural state they are colorless translucent solids.  The food trap in your picture contains blue pigment.  It is most likely harmless as it would be difficult to leach it from the PP in a aqueous media with a pH in the 3-10 range.  It is not likely that you'll be able to find out what the blue pigment it but you could put the plastic in a hot vinegar bath for an hour and check to see if the vinegar picks up any blue color.  Use distilled white vinegar so see the blue (if any) more easily.  If no color is transferred it is likely safe to use for cheese draining.  Otherwise find something else.  Likewise if the color changes then don't use it.   

[fredthecat]

Thanks so much for a perfect explanation. I'd gift a virtual cheese if I had any. I'll try the vinegar experiment and report back. If it doesn't leach colour, I'll have a wide variety of mold sizes for cheap prices.

[Danbo]

Just press the "Thumbs up"-link under Kern's name to the left - then he will get a virtual cheese! :-)

[Al Lewis]

I would guess that you're not going to see any color transfer from that food catcher. We do a lot of injection molding at the shipyard and the colorant is mixed at the time of the plastic being melted down, prior to injecting.  There is no way that colorant can come out of the molded product.  I also believe you may find a government standard, for anything that comes in contact with food, that requires the colorants to be locked into the plastic.

[Kern]

Just press the "Thumbs up"-link under Kern's name to the left - then he will get a virtual cheese! :-)

Aw, a virgin no more!