Kosher food is food prepared in accordance with Jewish dietary guidelines or "Kahrut" which means "proper." Any food can be called kosher food if it follows the proper guidelines. Conversely, foods typically labeled as "Jewish" aren't necessarily kosher. The word "kosher" isn't used for only food, however. Kosher basically means something follows all the Jewish legal guidelines.
Some of the laws governing kosher food claim that according to the Torah Processed food must be prepared in the presence of a rabbi. Deer, sheep and goats are all considered to be kosher food. Poultry and meat must be slaughtered under strict guidelines called "shechita." This means the animals are slaughtered without pain. Only those who are trained and qualified are allowed to slaughter kosher animals. Once the animal is no longer alive, another team of experts will examine the animal to be sure the animal is without illness, abnormalities or anything else that can be considered unsanitary. The lungs in particular must be pure. In addition, all blood and most fat must be removed.
Families who eat only kosher food must use two separate sets of utensils, pots, pans and dishes. One set is for poultry or meat, and another is set for everything else. In addition, these dishes and utensils can't be washed together. If a kitchen has two sinks, it is an ideal setup for a kosher family. If not, one set of dishes must be washed; the water emptied and sink scrubbed before the other set can be cleaned. Dishes and utensils must be dried using separate racks or dishtowels.
In determining whether a recipe you want is kosher one should bear in mind the basic concepts of kosher food: no mixing of dairy and meat; no pork or pork products; no shell fish. Any animal which does not both chew its cud and have a split hoof, such as rabbit or hare, pig, horse, dog or cat. All fruits, vegetables and grains are allowed.
Kosher recipes of traditional Jewish foods are rather healthy. Most of what we consider traditional Jewish food always seems to be high in sodium and fat. Times are changing. Food is refrigerated and few of us are so hungry that an intake of fat is needed for survival. None of this changes Halacha and the mitzvah of eating kosher foods. Taking risks with one's health has always been in conflict with respect for life.
In cooking book you may find a recipe of Kosher Beef. It is beef that is processed using specific guidelines of Jewish law and with the supervision of special rabbis. Kosher beef must also be cooked and consumed using specific guidelines. The strict rules of slaughtering have necessitated the creation of regional centers where the slaughtering is performed. The meat is then shipped to local butchers. Only the forequarters of a kosher animal are allowed for human consumption. For beef, this would include the area from the tenth rib forward. The hindquarters of the animal contain the sciatic nerve and fats, which are not allowed for consumption. This means that a wide range of beef cuts, such as sirloin and T-bone steaks, are not available as kosher products.
There is one curious fact worth of mentioning. An opinion that there is no such thing as "Traditional Jewish Food" is not as rare as one should think. As a people, jews have been allowed and occasionally invited to live in countries present and past for hundreds of years and then kicked out. What we call traditional Jewish food is food consistent with that of out previous host country. One should note that traditional Sephardic food is considerable different than Ashkenazic. Ignoring that complication, food is often regionally.