We have been discussing issues related to ritual hand washing. The Gemara on today’s daf (=page) asks whether in a situation where one person is feeding another the person who is doing the feeding – who is touching the food – must wash his hands and whether the person who is eating – but is not touching the food – must wash his hands.
Most of the commentaries explain that Shammai ha-Zaken was reluctant to rely on the “leniency” and wash his hand. The Sages ruled that he should therefore wash both his hands, because they wanted to emphasize that, in this case, there was no prohibition at all. The Ritva points out that there are several similar cases in the Talmud, where the Sages went beyond the letter of the law in order to emphasize the correct ruling. Rabbenu Yehonatan understands this case differently. He argues that Shammai ha-Zaken was concerned lest he touch the food with his unwashed hand, so he refrained from feeding his children entirely. The Sages reacted to this by insisting that he wash both hands.
What was the great concern about touching food?
The Gemara quotes Abayye as explaining that the Sages were afraid of shivta. Rashi explains that shivta is a ru’ah ra’ah – an evil spirit. According to the responsa literature from the period of the Ge’onim, shivta was a disease that affected mainly babies and younger children. From the descriptions that appear in the Gemara it seems likely that it is some type of contagious infection that can be carried by dirty hands.