Answer:
Social customs that involve kissing as a greeting can have microbiological implications as they may lead to the spread of infectious diseases. Kissing can involve the exchange of saliva, which can contain bacteria and viruses that can be transmitted from one person to another. For example, diseases such as the common cold, flu, and mononucleosis (also known as the kissing disease) can be spread through kissing.
In contrast, social customs that involve bowing or other non-contact greetings may reduce the transmission of infectious diseases. Bowing, for example, involves no physical contact and thus limits the exchange of saliva and other bodily fluids that can transmit diseases.
It is important to note, however, that the risk of transmission of infectious diseases is not limited to kissing alone. Other forms of physical contact, such as handshakes and hugs, can also lead to the spread of diseases. Therefore, it is important to practice good hygiene, such as washing hands regularly and covering the mouth and nose when coughing or sneezing, to reduce the risk of transmission of infectious diseases.