1. It is forbidden to eat fish with meat, even with the fat from fowl, because of the possible danger. Similarly, one should not roast fish and meat in the same oven unless one of them is covered. Nevertheless, there is no problem regarding our ovens, for they are large.
2. When a person eats fish, and then meat, or the opposite, he should eat some bread and drink something in between. Thus, it will be as if he had cleaned and washed out his mouth.
3. One must be careful of human sweat, for all human sweat is like poison, with the exception of sweat from the face. Therefore, a person should not place food between his clothes and skin because of sweat. Similarly, a person should not place coins in his mouth, because they might have come sweat upon them. Futhermore, they are handled by many people and may carry infection