What about ingredients?
Life used to be very simple. Food arrived in the kitchen without prepackaging and without all those delicious additives. As far as kashrut is concerned, modern food technology raises several problems, many of which have not yet been satisfactorily answered.
First, many common additives can be produced from either animal or vegetable sources; the original animal matter may undergo as many as three chemical processes. The source of the additive is then not determinable by chemical means: glycerol produced from animal fat is exactly the same as that derived from plants.
The quantity of non kosher additive and its function in the product must also be considered; there is a difference in a product which contains an ingredient and one where the ingredient determines the nature of the finished product. Thus, the same substance may render one foodstuff non kosher, while being perfectly acceptable in another.
The following is a partial list of ingredients that may or may not be problematic:
Emulsifiers & Stabilisers
Most modern processed foods contain one, and sometimes both, of these substances. Powdered foods especially require emulsifiers in order that the powder mixes easily with liquids. Unfortunately they are usually non-Kosher. In "E" numbers, these are in the 400 series.
Mono & Di Glycerides (Emulsifiers), (The 470 series of "E" numbers).
These are widely used in the preparation of baked goods and other food products. Other related emulsifiers that you must look out for are Polysorbates E430's and Monostearates F490's. They may not be Kosher.
Glycerides are processed from fatty acids, both animal and vegetable, and unless Kosher supervised and certified, they must be considered as non kosher.
Lecithin, another type of emulsifier used in chocolate products, is derived from soy bean or maize and is kosher.
Anti caking Agents: Calcium Stearate Magnesium Stearate (E572):
This powdery substance is produced from fatty acids (usually animal tallow) and is used as an anti caking agent in garlic and onion salt and numerous spice powders and blends. These products, therefore, should not be used unless Kashrut endorsed.
This glutinous material is obtained from beef, pork and calf and is usually non Kosher. Because of its congealing qualities it is used in a wide range of foods so you should therefore be careful to check the ingredients.
In a limited number of kosher products a specially produced kosher gelatin is used, derived from kosher prepared skins and meat of ritually slaughtered animals.
There are a variety of products which present no Kashrut problems and are used as substitutes for animal gelatin. These include Agar E406, Carrageenan E407, Vegetable gums E410 to E416
NOTE: that whenever the labels list "gelatin" as an ingredient it is definitely of animal origin.
Consumers are often puzzled when they find glycerin listed as an ingredient on kosher products. Originally, glycerin was produced commercially as a by product in the manufacture of soap from animal tallow. Today's technological advances in the food industry have made it possible to also produce glycerin from mineral and vegetable sources. All glycerin must, therefore, be Kashrut endorsed.
Vitamin preparations in tablet or capsule form often contain stearates, gelatin binders and coatings of non kosher origin. In other preparations, vitamins from natural sources, such as non kosher liver, bone meal and fish oils are used. Glycerin is used extensively as a base in liquid vitamin preparations. Where vitamin therapy is medically prescribed, the Kashrus Guide or a Rabbinic authority should be consulted.
Shortenings and Oils
In the UK "pure vegetable oils" can usually be relied upon to be just that, with no additives at all. Shortenings or margarine, however, require Kashrut endorsement.
Lactic Acid E270
This item, while in itself not a problem, often confuses consumers who assume that it is a milk product. Although it is possible to produce lactic acid from milk, commercial and industrial producers derive it from the fermentation of maize, molasses, or synthetically, and it is therefore Kosher and pareve.
LACTIC ACID IS NOT TO BE CONFUSED WITH LACTOSE, WHICH IS OF MILK DERIVATION.
EEC Numbers representing non kosher or dubious ingredients :
E120 E422 E432 E433 E434 E435
E436 E470 E471 E472(a) E472(b) E472(c)
E472(e) E473 E474 E475 E476 E477
E481 E482 E483 E491 E492 E493
E494 E495 E542 E570 E572