Twenty-first century technology and the intricacies of the global food industry make it impossible to know what is in a food product by simply scanning the label. A sampling of the ways ingredients can make it into the food but not onto the label:

  • Many additives used to enhance the flavor, texture and color of food are not kosher. Their names are often technical or vague (e.g. "natural flavors"), with the result that we do not know exactly what they are. All additives must also be processed on kosher equipment for the product to be kosher.
  • Only "ingredients" must appear on the label. Processing agents, release agents, and other substances, often of animal origin, are technically not considered "ingredients" and usually are not listed. For example, oils and fats used to coat the pans for baked goods are not listed as ingredients and are often not kosher.
  • Oils or shortening must be certified kosher and pareve. According to government standards, an ingredient may be listed as vegetable oil or shortening even when containing a small percentage of animal fat.
  • A food may be processed in a factory where non-kosher products are also prepared and the same machinery is used for both. The food produced in such a factory is non-kosher, unless a reliable mashgiach supervises the koshering of this equipment.
  • Not all ingredients are necessarily listed. If an ingredient falls below a certain percentage of the content, the government does not require it to be listed on the label.
  • The ingredients of a product may have been slightly altered, yet the manufacturer is allowed to continue using the same labels until new ones are printed.
  • Manufacturers of certain products, such as ice cream, are not required to list ingredients at all, and therefore may list them selectively.
  • Israeli products, which need special supervision, are often used by large companies. We would never be aware of their presence simply by reading the label.

Thus, foods are often not what they appear to be, and even the simplest products require certification. Even "pure apple juice" or "pure apple cider," with "no artificial ingredients or additives," may not be kosher. Apple juice is a good example of what may happen to a "natural" product when nature meets technology, so we will explore it in further detail.

"Pure apple juice" generally has gelatin (made from the skin, cartilage, bones and meat of non-kosher animals) added to remove the pectin from the juice and to give it a clear appearance. The pectin attaches itself to the gelatin and both are filtered out. Kashrut problems can arise in the filtering method or if the juice is heated before filtering. Even a "cloudy" juice, which would seem to indicate that no clarifying agent has been added, sometimes indicates the opposite: the gelatin has been added, but not totally removed, in order to give it a "natural" appearance.

In addition, the FDA (Food and Drug Administration) currently approves a number of different food colorings. Many are of natural origin, including fairly common red dyes derived from insects -which may be completely "natural" but are not kosher. Nutritional additives such as proteins, amino acids or vitamins may also be non-kosher or render a pareve product dairy. For example, some tuna fish is made dairy by virtue of the type of protein added.

For all of these reasons, we can only be sure that a food is kosher when all the ingredients, factories, and processes have been inspected by an expert. Reliable certification assures us of this.