I think the 'white goo' is probably the protective plastic film thats often on stainless steel sheetmetal.

The sinks are made seperate & the sheetmetal firm welds them into their stainless steel sinktop then grinds down the welds & sands/grinds/polishes the weld down till you can't see the weld from the top.



Bleach 'eats' stainless steel if its left on it long enough, so I found when I noticed tiny holes in my SS frypan, then the sinktop....