The implication is that those not listed are permitted. The rabbis of the Talmud, however, deduced four distinguishing marks of birds that are permitted. 2, no. 16, but see also Yad Halevi , Y.D. no. Handbook for Home and School , published by the Union of Orthodox Congregations. Our brethren from Yemen claim to be expert at the identification of permitted locusts and have eaten them.
Cheese is made from curdled milk.
Since the curdling agent was rennet, which is extracted from the walls of a calf's stomach, Cheese was forbidden as a mixture of dairy and meat. According to some authorities, however, the use of rennet does not affect the kashrut of cheese because rennet no longer has the status of food and instead is comparable to a mere secretion. The Committee on Law and Standards of the Rabbinical Assembly has decided to follow the lenient opinion. First of all, it reasons, the fears expressed by those who require a hekhsher applied only in former times, when cheesemaking was a cottage industry and there was no way to control the ingredients used. Under these conditions, there was always the danger that an individual farmer who made cheese might use the milk of a nonkosher animal or might add lard to the mixture.