Unless you grow all your food in your own garden and prepare all your meals from scratch, it's almost impossible to eat food without preservatives added by manufacturers during processing. Without such preservatives, food safety problems would get out of hand, to say nothing of the grocery bills. Bread would get moldy, and salad oil would go rancid before it's used up.

Food law says preservatives must be listed by their common or usual names on ingredient labels of all foods that contain them — which is most processed food. You'll see calcium propionate on most bread labels, disodium EDTA on canned kidney beans, and BHA on shortening, just to name a few. Even snack foods — dried fruit, potato chips, and trail mix — contain sulfur-based preservatives.

Manufacturers add preservatives mostly to prevent spoilage during the time it takes to transport foods over long distances to stores and then our kitchens. It's not unusual for sourdough bread manufactured in California to be eaten in Maine, or for olive oil manufactured in Spain to be used on a California salad. Rapid transport systems and ideal storage conditions help keep foods fresh and nutritionally stable. But breads, cooking oils, and other foods, including the complex, high-quality convenience products consumers and food services have come to expect, usually need more help.

Preservatives serve as either antimicrobials or antioxidants — or both. As antimicrobials, they prevent the growth of molds, yeasts and bacteria. As antioxidants, they keep foods from becoming rancid, browning, or developing black spots. Rancid foods may not make you sick, but they smell and taste bad. Antioxidants suppress the reaction that occurs when foods combine with oxygen in the presence of light, heat, and some metals. Antioxidants also minimize the damage to some essential amino acids — the building blocks of proteins — and the loss of some vitamins.

Safety Questions

Consumers often ask the Food and Drug Administration about the safety of preservatives, and if there's a system in place to make sure preservatives are safe.

Many preservatives are regulated under the food additives amendment, added to the Federal Food, Drug, and Cosmetic Act in 1958. The amendment strengthened the law to ensure the safety of all new ingredients that manufacturers add to foods. Under these rules, a food manufacturer must get FDA approval before using a new preservative, or before using a previously approved preservative in a new way or in a different amount. In its petition for approval, the manufacturer must demonstrate to FDA that the preservative is safe for consumers, considering:

• the probable amount of the preservative that will be consumed with the food product, or the amount of any substance formed in or on the food resulting from use of the preservative
• the cumulative effect of the preservative in the diet
• the potential toxicity (including cancer-causing) of the preservative when ingested by humans or animals.

Also, a preservative may not be used to deceive a consumer by changing the food to make it appear other than it is. For example, preservatives that contain sulfites are prohibited on meats because they restore the red color, giving meat a false appearance of freshness. (The U.S. Department of Agriculture regulates meats, but depends on the FDA regulation to prohibit sulfites in meats.)

The food additive regulations require the preservative to be of food grade and be prepared and handled as a food ingredient. Also, the quantity added to food must not exceed the amount needed to achieve the manufacturer's intended effect.

Regulations about the use of nitrites demonstrate the scrutiny given to the use of additives. Nitrites, used in combination with salt, serve as antimicrobials in meat to inhibit the growth of bacterial spores that cause botulism, a deadly food-borne illness. Nitrites are also used as preservatives and for flavoring and fixing color in a number of red meat, poultry, and fish products.

Since the original approvals were granted for specific uses of sodium nitrite, safety concerns have arisen. Nitrite salts can react with certain amines (derivatives of ammonia) in food to produce nitrosamines, many of which are known to cause cancer. A food manufacturer wanting to use sodium nitrites must show that nitrosamines will not form in hazardous amounts in the product under the additive's intended conditions of use. For example, regulations specify that sodium nitrite, used as an antimicrobial against the formation of botulinum toxin in smoked fish, must be present in 100 to 200 parts per million. In addition, other antioxidants, such as sodium ascorbate or sodium erythorbate, may be added to inhibit the formation of nitrosamines.

As scientists learn more about the action of certain chemicals in our bodies, FDA uses the new data to reevaluate the permitted uses of preservatives. Two examples are the commonly used preservatives butylated hydroxyanisole (BHA) and sulfites.

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Tags: Food Safety

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.