We're baking a ton of meringue cookies for a party this weekend, so I picked up a carton of egg whites. It wasn't until after I got home that I noticed a warning stating:
"Due to pasteurization, liquid egg whites are not recommended for whipping or meringues."
I don't quite understand this. While pasteurization could denature proteins if the temp goes too high, the eggs whites generally shouldn't be getting hot enough for that to really happen. Further, you can buy dried egg whites at grocery stores labelled as "instant meringue" and those are also pasteurized.
I went ahead and whipped them anyway, and they seem to have worked just fine. The peaks could be stiffer if I had beaten them longer, but I was working quickly and just needed them to come to a reasonable piping stiffness.
I'm just trying to understand the rationale of the warning on the label. Is it also a matter of age? Maybe these were fresher?