How do kosher food preparation requirements compare with what is known by modern science to make food safe for eating?

Question

As discussed in What are the requirements for a dish to be kosher?, kosher food must follow various rules and procedures. I noticed a pattern in these rules which suggests some consistency with modern food scientists' understanding of food safety and handling.

For example:

• Shellfish often contains harmful bacteria which can make one sick. Avoiding this is probably good advice.
• Many fish or "creatures of the sea", that do not have scales, contain dangerous poisons and are probably best avoided.

Are there any scientific explanations for why it might be good to avoid the other food? E.g.:

• Meat in which the blood has not been drained.
• Eating milk together with meat or cooking beef in milk.

Pigs are often fed garbage and other meat, including meat from other pigs. Could this lead to diseases similar to mad cow disease?

Answer 1

Interesting question and I'll try to give an answer to the questions that you state explicitly.

Blood is edible and is eaten in loads of countries. Black sausage comes to mind. However, blood tends to coagulate rather fast and meat needs a fair amount of time to mature. I'm guessing that leaving blood in the meat will give the meat dark spots that are not appealing, therefore the prohibition.

Milk and meat are eaten together at least in Spain. The only reason I can imagine for not mixing them is historical. Originally the Jewish tribes lived in a desert. A hot climate and food... don't go well together. Maybe milk turned sour fast, or it turned into yoghurt, and maybe that was feared...

All this is just guessing, so anybody that finds a valid reference is welcome to post here.

Answer 2

While some of the kosher rules are food-safety rules developed by the Israelite priests (or given by God), the prohibition against mixing meat and milk is because of an ancient ritual that involved cooking the meat of a slaughtered animal in its mother's milk, a religious practice forbidden in Exodus 34:26 "... You shall not boil a kid in its mother's milk", part of a passage sometimes known as the ritual decalogue that prescribes the destruction of artifacts of other religions, forbids the creation of idols, and lays out other religious responsibilities.

The laws regarding separation of meat and milk come from the concern that a person might accidentally break this law and boil a kid in its mother's milk if they purchase both meat and milk and prepare them together, or if a residue of milk is left on cooking utensils from a previous dish, which then gets into a dish involving the meat of a slaughtered kid.