Plaster, Wood, and Sand in My Grated Cheese?

The other day, my wife and I went to the local grocery to purchase the components for a baked salmon casserole. One of those ingredients is grated cheddar cheese. For convenience, my wife normally buys the pre-grated kind. Being a retired chemist, I thought I'd check the label of one or two well-known brands. The labels included calcium sulfate, silica, and cellulose among the ingredients. In all fairness, these substances, in small quantities, are not dangerous. Still, are these additives desirable to eat? First, we will discuss each of these chemicals, individually; then we will consider what can be done to eliminate them.

Calcium Sulfate

Calcium sulfate, chemically CaSO₄, is the white powdery solid derived from processed rock. It is sometimes called gypsum, or Plaster of Paris, though commercially sold Plaster of Paris often contains additional substances. Calcium sulfate is commonly found in the western United States. One of the most common building materials in use today, wallboard, is largely calcium sulfate. This chemical is inexpensive, is admittedly a source of calcium, and acts as a dessicant.

Cellulose

Cellulose is an insoluble carbohydrate - a polysaccharide - and is the primary constituent of wood found in trees. It can be identified with ordinary sawdust. It is sometimes referred to as "dietary fiber," though cellulose used in foods would be carefully processed; sometimes it is listed as microcrystalline cellulose. Cellulose prevents slivers of cheese from sticking together, thus it is useful for avoiding clumps in packages of commercially grated cheese.

Silica

Silica (silicon dioxide), chemically SiO₂, is the "correct" name for purified sand. Silica powder, food grade, is added as an anti-caking agent to improve flow. Certainly, one wishes to see a freshly opened package of grated cheese pour out its contents as individual slivers, rather than in clumps. Silica imparts this property because it is an excellent dehydrating agent - preventing moisture from settling on surfaces. If the particles of "sand" are extremely small, the large surface area of the particles can accomplish this job with the use of only a small quantity of additive. In some products, silica may be added in the form of silicates or aluminosilicates.

Eliminating These Chemicals

Although these chemicals found in ordinary grated cheeses are generally recognized as safe, many consumers are rightly concerned about the cumulative effects that could conceivably result if all the food they eat contains added chemicals. Even though it would be impossible to point to some specific individual's death as arising from the food additives he or she consumed over a lifetime, the rise in cancer and other diseases has brought renewed interest in "eating natural." Happily, in the case of grated cheese, it is a relatively simple matter to get rid of the calcium sulfate, cellulose, and silica found from our diet. Simply buy block cheese and grate it yourself.