I use steel with a non-heat-conducting handle.

With silicone, there's no telling what it is contaminated with. Refer to DOI 10.1016/j.polymertesting.2016.09.021 titled "Extraction, confirmation, and screening of non-target compounds in silicone rubber teats by purge-and-trap and SPME combined with GC-MS" (2016).

Large discussion 16 days ago (475 points, 844 comments) https://news.ycombinator.com/item?id=41996156

a larger discussion would center on our growing abilities to confirm exactly which substsances and compounds ,found in any domestic environment, are causing demonstrable harms to the most people, and eliminate those. with some sort of regulatory control stating, "thou shalt not contaminate the sanctity of the human domestic environment,by chemical or other bio disruptive inputs" and introduce catestrophic penaltys for those that do