The tenets of kashrus (kosher dietary laws) are rooted in the Written and Oral Torah (the Bible). In the post-Biblical era, the rabbis elaborated upon these laws with explanations, details, and organization. These laws determine which foods are acceptable and conform to the Jewish Code.
The word kosher is an adaptation of the Hebrew word meaning “fit” or “proper.” It refers to foodstuffs that meet the dietary requirements of Jewish Law.
The barometer of kosher and non-kosher depends on two variables: the source of the ingredients and the status of the production equipment. Kosher certification, which is the guarantee that the food meets kosher requirements, revolves around these two criteria.
A common misconception is that kosher reflects the conferring of a blessing on food by a rabbi. There is no truth to this whatsoever. Although Jewish ritual does require the recitation of a blessing prior to the consumption of food, there is no blessing which can make the food itself kosher or non-kosher.