Frozen Pizza: Some Hot Kashrus Issues

The role of pizza in America and the general Western world has undergone a major transformation in the past quarter century. Prior to the late 1970’s or early 1980’s, pizza was considered a novelty; most people certainly did not think of it as a staple, real meal food. Typically, a town had a pizzeria owned by an Italian family, and the pizzeria served the purpose of providing pizza for special ‘nosh‘ purposes, such as children’s birthday parties, where ‘junk food’, including pizza, ice cream and soda were served. Aside from birthday parties, pizza was associated with home sports events and leisure activities: a group of men would order in pizza to accompany a football game, or an informal youth event would occasionally be capped off with pizza.

Times have certainly changed. Once Western society began to realize the nutritional value of pizza, it was pretty much declassified from ‘junk food’ status and made a staple in the eating habits of the masses. School lunch menus now feature pizza, and pizza chain stores and franchises are found all over the globe. An old-style Italian pizzeria is now more of a relic than the norm.

As the Yiddish saying goes, that which general society does is mimicked by Jewish society, and pizza has thus gained great prominence and normalcy in the Jewish world. Most cities that serve a kosher consumer base have one or several kosher pizza shops, and there are over a dozen national brands of kosher frozen pizza currently available.

Unlike most of the baked and dairy foods featured in this series, the manufacture of pizza is rather simple. Its kashrus issues are also not too numerous, but they are very sensitive and warrant discussion.

Production of Kosher Frozen Pizza

How is pizza made? Typically, raw dough consisting of flour, water and other ingredients standard to simple bread dough is produced. The dough is subsequently covered with tomato sauce, then cheese and toppings as desired, and the product is baked for approximately 15 minutes.

Of course, there are varied permutations of every ingredient used. The dough may contain conditioners in order to provide a specific texture. Tomato sauce is often specially seasoned for use on pizza; such pre-seasoned sauce is industrially termed ‘pizza sauce’. Although pizza almost always utilizes mozzarella cheese (due to its elastic texture that provides smooth melting quality and does not easily run), some pizza manufacturers add edam, muenster and cheddar cheese as well, while others omit mozzarella cheese altogether.

The above description of pizza production applies to fresh pizza sold in pizza shops and to some types of frozen pizza. These varieties of pizza are fully baked by the manufacturer, with the sauce, cheese and toppings being baked in an oven with the dough.

However, in the case of other forms of frozen pizza (typically the older types), only the dough is baked. The rest of the ingredients – sauce, cheese and toppings – are added raw after the dough has been baked and cooled, and the product is then frozen for the consumer to himself heat, at which time the fresh-frozen sauce, cheese bits and toppings will be baked.


The most kosher-sensitive ingredient in pizza is cheese. Halacha (Yoreh Deah 115:2) stipulates that cheese made by non-Jews is fully non-kosher. This cheese is called ‘gevinat akum’, and the consensus among the vast majority of poskim is that gevinat akum is deemed non-kosher even if all of its components and enzymes are kosher. (See Gemara Avodah Zarah 29b and 35a and Rambam Hil. Ma’achalot Asurot 3:13-15.) Gevinat Yisrael – kosher cheese – requires full-time supervision of a Yisrael according to the Rema (ibid.), and the Shach (ibid. s.k. 20) rules that a Yisrael must personally add the (kosher) rennet enzyme during cheese-making in order for it to be kosher. (The rule of gevinat akum has nothing to do with chalav akum and chalav Yisrael; even those who consume chalav stam are prohibited from eating gevinat akum.)

Because of the hashgacha costs involved in manufacturing kosher cheese (its price is usually far higher than its non-kosher counterpart) the incentive for companies to cut corners and use non-kosher cheese is great. Thus, the tightest of hashgacha controls must be in place when dealing with kosher products that contain cheese, and pizza is surely no exception.

The only real kashrus concern pertaining to dough is the use of dough conditioners, as they may contain enzymes or other problematic components. (Of course, as with all baked grain foods, challah must be reliably separated as well.)

Tomato sauce is often made in plants that use non-kosher cheeses and meats for some of their production, and there is a serious risk of shared factory equipment for both pure tomato sauce and tomato sauce that has cheese or meat content. (This is why so many brands of tomato sauce do not bear recognized kosher symbols.) Obviously, a kashrus agency must be very careful when dealing with tomato sauce sources.

‘Mixed’ Pizza Factories

Although most kosher pizza is made in fully-kosher facilities, some kosher frozen pizza is produced in ‘mixed’ plants that carry on kosher and non-kosher manufacture. These facilities are non-kosher most of the time, and they schedule special kosher campaigns with a kashrus agency once in a while, usually to produce kosher pizza under a special brand.

How is kashrus monitored in these situations?

If the plant makes old-style frozen pizza, where only the dough is baked in the oven, it is fairly straightforward, as the oven is not in contact with non-kosher cheese or toppings. If it can be verified that the dough itself is kosher – which is often the case – then the oven needs no kashering prior to kosher production campaigns.

However, if the oven is used to bake the entire pizza – cheese and all – then it will need to be kashered before kosher production. This is a very labor-intensive procedure. The oven needs to undergo ‘libun’, meaning a total burn-out, requiring it to be turned on or torched to about 1000 degrees, all under a mashgiach’s supervision. The oven’s trays also need to be exposed to this intense, scorching heat.

Libun is only required for equipment that has direct exposure to fire. Other equipment used for non-kosher production needs ‘hagalah’, meaning a boil-out or scalding. Therefore, in the case of mixed pizza facilities that bake non-kosher cheese and toppings with the pizza dough, belts and trays that convey and handle hot non-kosher pizza all need to be immersed in boiling water in order to be kosher.

Mixed pizza plants have other kashrus concerns as well. Unlike in a consumer setting, where cheese is purchased in slices or small pieces, most pizza producers buy large industrial-size blocks of cheese that are shredded at the pizza factory right before use. If the cutters used for shredding the kosher cheese are shared with non-kosher cheese, they need to be abrasively cleansed under the watch of a mashgiach, who will inspect them for cleanliness upon completion.

Additionally, in the case of old-style frozen pizza plants, where cold tomato sauce and cheese bits or shreds are added to the product once it is cooled, there is an area where much care and caution must be exercised. These facilities usually perform a ‘pre-melt’ to the product just before freezing and packaging it, in which the pizza passes through a set of heating elements on a metal belt for half a minute or so, ever so slightly melting the cheese and toppings onto the dough. This melting process is not detectable when viewing the pizza in its frozen state, but its effect is very discernable, as without it, the cheese bits and toppings would totally fall off the pizza in the box.

The mashgiach who supervises such production at mixed pizza operations must carefully determine any areas of contact and be prepared to kasher as necessary.

The Proper Brachot for Pizza

Although this column is not a forum for psak halacha, and the reader must consult his personal moreh hora’ah for actual procedure, it would be irresponsible not to touch upon the brachot to be recited before and after consuming pizza.

As noted earlier, pizza was in previous times regarded as a ‘junk’ or snack food; rarely would people make meals around pizza. Thus, although some poskim have always maintained that pizza is a form of bread and requires Netilat Yadayim, Hamotzi and Birkat HaMazon under all circumstances, common halachic thinking has been to classify pizza as Pas Ha-Ba B’Kisnin – baked dough food that is not inherently classified as true bread (such as pie, cake or crackers), upon which one recites Mezonot and Al HaMichya when eaten as a snack and Hamotzi and Birkat HaMazon when eaten as a meal. Since pizza was usually not served as a meal food, common rule-of-thumb for many people was that pizza necessitated the recitation of Mezonot and Al HaMichya.

However, in light of the current role of pizza, such that it is often eaten as a meal, there is compelling reason to require that one wash, say Hamotzi and Birkat HaMazon when eating it under most circumstances. Here are some of the factors for this:

  • If one eats an amount of Pas Haba B’Kisnin that is equivalent to the total volume of food that the average person would consume in a typical meal, he must wash and recite Hamotzi and Birkat HaMazon. (Shulchan Aruch Orach Chaim 168:6 and Mishnah Berurah s.k. 24) According to this, if one eats an amount of pizza even as a snack that equals the volume of food that makes up a regular meal, he must wash, recite Hamotzi , as he is considered to have been ‘kove’a seudah’ (made a meal) out of his pizza.
  • If one eats Pas Haba B’Kisnin as his meal, and he is satiated from it, he must typically wash and say Hamotzi Only if he eats an amount so small that the average person would consider it too meager to serve as a meal would Mezonot and Al HaMichya be recited (Shulchan Aruch ibid.). Therefore, making a meal out of pizza would usually require washing, Hamotzi, and Birkat HaMazon, unless the average person would deem the amount consumed too small to be his meal, which is not usually the case.
  • If one eats Pas Haba B’Kisnin along with other foods, and the amount of Pas Haba B’Kisnin equals the amount of bread that would accompany the other foods in an average person’s meal, he must wash and recite Hamotzi and Birkat HaMazon (Mishna Berurah). Accordingly, if – for example – a person eats a slice of pizza and a soup or salad for lunch, and the volume of pizza dough is the same amount of dough that would be eaten in the form of a bagel or roll for lunch with that soup or salad (or whatever else), then the person must wash etc.

It must be emphasized that these halachos apply to all types of Pas Haba B’kisnin, including dough baked with apple juice.

Thus, the next time you take a bite out of a delicious slice of warm pizza, remember that a kashrus agency (hopefully) addressed the multiple halachic issues pertaining to that slice.

OU Kosher Staff