RE: EGG
Allergic infection is one thing. The main thing is the egg, quite commonly, has a deadly bacteria called salmolena. Event adult can be sick if got infected, but since our immune system is strong, we are usually okay, but there are seriously infected cases in adult also (meaning when you are sick, avoid half boil egg). But for baby, NO EGG WHITE AT ALL can be allowed. Though theorectically, the bacteria should have been killed by hard boiling, but you don't want to "what if", do you?
Blessedbaby, yes, according to the teacher (with >10 years of experience with infant), the correct way to intro egg yolk to young babies is to give baby 1/4 of hard boil egg during the day. Monitor carefully. If okay, give 1/2, then 3/4, then finally 1 whole egg yolk. If baby has family history of allergy/ashtma, egg is a NO-NO.