Making a kosher pizza is much like preparing any type of kosher food in that all of the kosher food regulations must be followed. In the specific case of pizza there are a few key ingredients which must be specifically prepared to ensure that the pizza is kosher.
The Proper Cheese
For any cheese to be deemed kosher, it must be made under the supervision of a Jewish person who is knowledgeable in the intricate laws of kosher food production. The cheese must also contain an added ingredient called rennet. In addition, this enzyme must be added only by a Jewish person to ensure that only kosher rennet is used in the process.
A less commonly considered aspect of kosher pizza is the crust. Any grain used to make the flour for the crust must adhere to kemach yashan which is a law that states that the grain being used had taken root prior to Passover of the present year. This aspect of kosher law is strictly followed in Israel but some Jews in other countries are not required to abide by this law.
True kosher pizza can never be prepared during Shabbos, the Sabbath Day. And according to kosher law, dairy and meat can never be mixed so kosher pizza can never contain any meat. Instead of meat, many kosher pizzas are made with added spices, herbs and a variety of kosher cheeses to increase the flavor and variety of the meal.
Kosher Law Applies
As with any dish, all kosher food laws must be followed to the letter for pizza or any dish to be considered kosher.