Please can you help me with this question? My mother came back from a trip to Israel and the people who she was staying with told her that she just found out from her son that you may NOT peel eggs before Shabbos. I have asked various Rabonim here and none of them had heard of this. One woman who overheard the question said that when she went on a Mashgiach course she was told that concerning eggs and raw onions. Do you have any more info for me?
The Talmud in Tractate Niddah 17a says that eating eggs onions or garlic that were peeled and left overnight is dangerous, as it is susceptible to "ruach ra'ah" (evil spirit". According to some opinions, this is no longer applicable, as ruach ra'ah is not known in our locales, and for this reason the custom is not universal. However many poskim do say that one should be careful, and many people are in fact careful about not peeling or cracking eggs and leaving them overnight. If part of the egg shell (on hard boiled eggs) or part of the peel on the onion and garlic iis left intact, one need not be careful. According to Rav Moshe Feinstein, this stringency does not exist when the peeling is done for long term (industrial) use, so that it is not a concern in bought foods.