以解决这个争论。我记得版主也说过应限制携带者从事饮食行业，但是有报道说食品安全法已经允许了，不知美国的情况怎么样
http://news.sina.com.cn/c/2009-07-29/060816029867s.shtmlblackbox给出的链接有关于saliva和food传染性
Don’t pre-chew food for babies.
Can HBV be transmitted in daycare via saliva, e.g., drooling infants?
Though HBV has been found in saliva, there are no data to suggest that saliva alone transmits HBV infection. There have been reports of HBV transmission when an HBV-infected person bites another person. In these reports, bloody saliva was usually present in the infected person’s mouth and the blood was more likely the vehicle of transmission. HBV is not spread by kissing, hugging, sneezing,coughing, food or water, sharing eating utensils or drinking glasses, or casual contact.
What is the risk for transmitting HBV by oral sex?
There are no specific data on transmission of bloodborne viruses through oral-genital sex. Saliva has not been associated with HBV transmission unless biting has taken place.
Can "French" kissing transmit HBV?
While HBV has been found in saliva, there are no data to suggest that kissing transmits HBV; however, there have not been studies to specifically look at "French" kissing.