How Does the OU Certify… Cheese, Flavors, Lettuce

OU Kosher Staff

How Does The OU Make Kosher Cheese for Pesach?

by Rabbi Avrohom Gordimer

Cheese is the most kosher-sensitive dairy product—and Passover is no exception.

What makes cheese so sensitive from a kosher-for-Passover perspective?

The two main ingredients that turn milk into cheese are cultures and rennet.

Cultures that are used in cheese-making to acidify the milk impact cheese’s flavor and texture; whether a vat of milk produces parmesan, Swiss, cottage or cream cheese is determined by the cultures, as well as the temperature to which the vat is heated. In the case of “soft cheeses” such as cottage and cream, the cultures are THE absolute most important ingredient, as rennet is typically not used.

Rennet is the enzyme that performs the physical conversion of milk into hard cheese. Rennet can come from animal stomachs or from other natural or synthetic sources. Obviously, OU-certified cheeses use only natural or synthetic rennet.

Cultures and rennet are commonly produced from materials that pose a Passover concern. Cultures can be nourished and grown on substances that are chametz—such as bleu cheese cultures, which are grown from bread—and they also commonly share the same processing equipment as non-kosher materials.

Rennet can be grown on glucose that is nourished on real chametz. Similar to cultures, rennet often shares processing equipment with substances deemed to be chametz.

Cheese factories typically need to be kashered before the manufacture of kosher-for-Passover products, since the manufacturing and packaging equipment is shared with non-Passover products year-round. OU-certified Passover cheeses are always manufactured with a mashgiach temidi, who is present and involved with the process from before the kashering of the equipment and facility all the way through to final packaging. 

How Does The OU Certify Flavors for Pesach?

By Rabbi Nosson Neuberger and Dr. Avraham Meyer

FLAVOR: The mysterious ingredient added to almost all processed foods that completes the gastronomic experience. As it is an important component in many OU-P products each flavor must be specifically certified for Pesach before it can be incorporated in the finished product or used as an ingredient in processing, cooking or baking an OU-P certified product.

What is involved in this extra certification process of making flavors kosher for Pesach as well?

What is a flavor? A typical flavor will have more than 50 flavor-chemicals combined together. These mixtures are formulated by a “flavorist” to give a food product a unique flavor.

So, what’s so hard? Just make sure that the ingredients are not natural and you know that none of the five grains (wheat, rye, barley, oat and spelt) are included, since all of the ingredients will be artificial. A basic challenge to this premise is that even when a product says that it has artificial flavors, there may be a Pesach issue because “artificial” does not preclude the use of natural ingredients!

Granted, ingredients that are derived from nature and earn the right to be called natural are more expensive than synthetic or artificially derived ingredients, but often due to availability or other reasons, natural ingredients may be used in a flavor that is still referred to as artificial.

Other items that are addressed together with flavors are fragrances, since many of the same companies that manufacture flavors make fragrances as well. While fragrances do not present a kosher challenge for year-round use, since they are not ingested, and Jewish law only requires items that are eaten to be kosher, Pesach rules stipulate that no leavened material be owned by a Jew over the course of the Pesach holiday. This necessitates Pesach certification of fragrances unless they are totally inedible to the point that even a dog wouldn’t eat them.

What are the general guidelines for Pesach flavor certification?

All components and processing aids need to have Pesach certification. This in turn makes it necessary for any item derived from wheat, rye, oat, barley or spelt be replaced. In addition, substitutes for derivatives of legumes, including corn, must be used because of the Ashkenazic restriction against eating kitniyot on Pesach.

Case in point where the OU addressed a flavor chemical used in production, is THF.

What is THF? TetraHydroFuran

What is the Pesach concern with THF? The F stands for Furan that can be derived from the husks of oats. Furan also can be derived from the husks of grains, and though husks should be possible to be approved, if steam is used to loosen the husk from the grain, there can be absorption of the grain into the husk—rendering it chametz.

The OU sent its representative to follow the supply chain of Furan all the way up to the distributor over many thousands of miles to confirm its production processes.

Luckily, the greatest concern was on the part of the distributor who feared the rabbi would open a competing field in Israel—despite the agricultural challenges. Once his fears were allayed the interview continued and the rabbi was able to certify the end product as kosher-for-Pesach use.


Enjoy a flavorful Pesach!

How Does The OU Certify Whole Leaf Romaine Lettuce for Pesach?

Rabbi David Bistricer & Rabbi Iser Fuchs

A great contemporary kosher challenge is ensuring that vegetables are clean of insect infestation. Insects are forbidden according to Torah law, and there is a rabbinic requirement to check those vegetables that are commonly found to house insects. Although the FDA has thresholds for insects in produce, kosher requirements are far more stringent. For example, the U.S. government allows up to 60 insects per 100 grams of broccoli and 50 insects per 100 grams of spinach—kosher law allows for none. It’s not uncommon for a product to fall within the FDA tolerance and still fall short of kosher requirements, posing a serious challenge for the kosher certification community when approving and kosher-certifying the infestation-prone Romaine lettuce. This challenge is particularly acute when the lettuce is sold as whole leaves—commonly used at the Seder as maror—and not chopped or shredded.

Ensuring that vegetables are insect-free is a daunting task. Constantly changing environmental factors directly impact the presence of insects in produce. This has posed a great challenge for growers and kosher-certifying agencies. Nevertheless, innovation and creativity have made kosher, bug-free vegetables a reality.

Vegetables are greenhouse grown, which in addition to providing infestation control, greatly minimizes the risk of bacteria and other safety concerns. As an added benefit, fewer pesticides are used than with their traditionally grown counterparts. A team of experts ensures that products conform to the highest quality, as well as FDA, HAACP, GMP, and OU guidelines.

These individually owned and operated growing ranches are in exclusive control of their product from seed to bag. Specialized growing programs have been introduced, outside product is not used, and all products are checked regularly by a mashgiach throughout the entire growing process to monitor the harvest.

Once the harvest is initially approved, it is shipped to a packing facility for further processing in a state-of-the-art facility utilizing sophisticated machinery to further test and triple wash each product. Samples are taken pre and post washing by a team of mashgichim, who continue the checking process to ensure that all products are free of any possible infestation. The mashgichim check the samples in a dedicated area—a modern laboratory that allows them to comfortably and effectively inspect the vegetables.

Currently the only whole leaf romaine lettuce approved by OU is manufactured by Kosher Gardens (see Consumer Guide Page 49).

How to check lettuce at home

Romaine lettuce is commonly used as maror at the Seder. This lettuce type is known as an open leaf variety. This means that as they sprout from the ground, the leaves begin to open up like a flower. Toward the end of their growth, the leaves begin to close around the stalk. Since romaine lettuce grows in an open fashion, it is much more prone to insect infestation throughout the head than other varieties of lettuce that primarily grow as a closed ball.

The insects most commonly found in open leaf lettuce are small black or green aphids and thrips. The leaves of the vegetable often camouflage these insects. The open structure of these vegetables allows insects to penetrate the entire head. Often, insects may be found between the innermost layers of leaves of an infested head. Therefore, each leaf must be washed and checked individually. The use of a light box for checking lettuce can be extremely convenient and helpful. However, even if a light box is not used, it is crucial to examine both sides of each leaf against a good source of light.

The following are step-by-step recommendations to properly check romaine lettuce for insects:

  1. Cut off the lettuce base and separate the leaves from one another.
  2. Soak leaves in a solution of cold water and soap. The proper amount of soap has been added when some bubbles are observed in the water.
  3. Agitate lettuce leaves in the soapy solution.
  4. Spread each leaf, taking care to expose all its curls and crevices. Using a heavy stream of water or a sink hose, remove all foreign matter and soap from both sides of each leaf. Alternatively, a vegetable brush may be used on both sides of the leaf.
  5. Leaves should be checked over a light box or against strong overhead lighting to verify that the washing procedure has been effective. Pay careful attention to the folds and crevices in the leaf where insects have been known to hold tightly through several washings.

Occasionally, worms may be found in burrows within the body of the leaf. Look for a narrow translucent burrow speckled with black dots breaking up the deep green color of the leaf. These burrows will often trap the worm within the leaf. To rid the leaf of these worms, carefully slit the bumpy part within the burrow with a sharp knife and remove the worm. It is important to note that many of these varieties feature curly leaves with many folds in which the insects tend to hide; therefore it is recommended they be washed and checked with extreme caution.

OU Kosher Staff

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