The Kosher certification concerns religious rules governing eating habits of practising Jews. The Hebrew word “Kosher” or “Kasher” means fit or proper, and it indicates that a food product has been produced in compliance with the dietary regulations prescribed by the Bible (the Torah). Kosher foods are widely traded especially in the Unites States where also Muslims, Hindus and vegetarians and allergic consumers consider the kosher certification as the most reliable for the analysis of ingredients. The biblical rules allow eating only ruminant animals and biungulates (cattle, sheep and goats, and wild animals such as deer) if slaughtered by experts in the prescribed manner and therefore not camels, rabbits and pigs; only fish with fins and scales and therefore not mollusks or dogfishes; and only domestic birds such as chickens and not birds of prey. It is forbidden to eat insects and food that contains blood, and mix meat and dairy products. While certifying products such as olive oil is quite simple, the certification of food products which contain many ingredients can become very complicated because of these limitations: all the ingredients in a food product must be kosher and the machines used for the production of non-kosher products can be used for kosher products only after being subjected to heated cleaning.