BACKGROUNDER
Sulfites
1. What are sulfites?
Sulfites, or sulfiting agents, are sulfur-based substances used primarily as preservatives. Six are used by the food industry: sulfur dioxide, sodium sulfite, sodium bisulfite, potassium bisulfite, sodium metabisulfite and potassium metabisulfite.
2. Why and how are sulfites used?
They are used primarily to reduce or prevent spoilage and discoloration during the preparation, storage and distribution of foods. The products so treated include processed potatoes, many dried fruits, dehydrated vegetables and some seafood, especially shellfish. Sulfites retard browning and inhibit the deterioration of such nutrients as vitamin C.
Sulfites also are used to bleach food starches, to condition dough for some baked goods, to control fermentation of wine and to soften corn kernels during the wet-milling process.
Until recently sulfites were used to help maintain the fresh appearance of fresh fruits and vegetables in salad bars and produce departments. When safety concerns were raised in 1984, the Food and Drug Administration (FDA) banned the use of sulfites in salad bars and produce departments. Presently, FDA has one unfinished regulation on the use of sulfites in potato products: The courts set aside a ban on sulfites in raw, peeled potatoes/potato products; and FDA has yet to rule on their use in dehydrated and frozen potato products, and in raw, peeled potatoes/potato products.
Sulfites are used in a substantial number of prescription and over-the-counter drugs to help maintain their potency and stability. A chart provided at the end of the paper lists the types of foods and drugs that may contain sulfites.
3. Do sulfites appear naturally in food?
Naturally occurring sulfites exist in a few foods, especially in fermented products, such as beer, wine and wine coolers. They are produced by yeasts in the fermentation process. Even wine marketed as "sulfite-free" contains small amounts of naturally occurring sulfites.
4. Are sulfites dangerous?
Sulfites pose no hazard to most Americans, according to a report released in January 1985 by the Federation of American Societies for Experimental Biology (FASEB), an assessment supported by other scientific panels. For a specific segment of the population, however, sulfites pose a definite, documented health risk. Reported reactions cover a wide variety of symptoms - from hives, nausea and diarrhea to respiratory failure. The most often reported reaction is asthmatic attack. Such an attack can be caused by ingesting sulfites or inhaling sulfur dioxide gas.
The link between sulfites and asthma has been well established through a variety of testing methods, but other reactions, including hives and nausea, have not been substantiated. Scientific authorities believe more studies are needed to verify a definite cause-and-effect relationship between sulfites and such reactions.
5. Who is sensitive to sulfites?
Sulfite sensitivity appears to occur almost exclusively in severe asthmatics, although some reports of sulfite reactions indicate that a small number of non-asthmatic individuals also may be at risk.
Estimates of the total number of affected individuals are conflicting. One study suggested that 8 percent of all asthmatics, or approximately 720,000 people, may be sensitive to sulfites. More recent research indicates that only 100,000 to 200,000 asthmatics may be sulfite-sensitive.*
Thresholds for sulfite sensitivity among the affected population vary. Individuals with higher thresholds are not likely to have problems with dietary sulfites, but those with lower ones could ingest a provoking dose in a single meal. To make matters more complex, asthmatics may respond one day and not another, depending on the natural course of their illness.
6. Do sensitive individuals react to all sulfited foods?
Some sulfited foods do not elicit asthma in sulfite-sensitive individuals, according to ongoing studies at the University of Wisconsin Clinical Sciences Center. A leading researcher, Dr. Robert Bush, believes that most sulfite-sensitive asthmatics do not react to residues (sulfites remaining in food after treatment) below 100 parts per million (ppm), although he says more research is needed because reactions may depend on a combination of factors, including the level of sulfite residues, the sensitivity threshold of the individual and the type of food consumed. Non-dietary factors also may play a part.
7. Are there alternatives to sulfites?
A variety of alternatives are available for some products, including salads and other greens, fruits and juices. Members of the potato industry maintain that alternatives for use on precut potato products are not as effective as sulfites. A national consumer advocate group, the Center for Science in the Public Interest, disagrees. They point out that there are several sulfite-free processed potato products. No acceptable substitutes for sulfites have been found for use on dried fruit, corn syrup or shrimp.
8. Who regulates the use of sulfites?
The FDA regulates sulfite use in drugs and food, except for meat and poultry, which fall under the purview of the U.S. Department of Agriculture (USDA). The Bureau of Alcohol, Tobacco and Firearms (BATF) regulates the use of sulfites in alcoholic beverages. Use of sulfur dioxide as a fungicide on grapes comes under the authority of the Environmental Protection Agency (EPA). Regulations involving grapes are discussed below.
9. Why did FDA ban the use of sulfites on produce?
For years, FDA included sulfiting agents on its Generally Regarded As Safe (GRAS) list and permitted their use on fresh produce and a wide variety of processed foods and medications.
Following a government investigation of more than 500 reports of allergic reactions, including 13 deaths, the agency banned the use of sulfites on fresh fruits and vegetables - including those imported into the United States. Raw produce was targeted because more than 40 percent of the complaints received involved reactions following consumption of fresh fruits or vegetables. Another 15 percent of the complaints involved wine and beer, while 14 percent involved various processed, packaged foods eaten at home.
10. What is the impact of the ban?
The ruling has limited impact on the food industry because most restaurants and supermarkets voluntarily stopped using sulfites on their salad bars and produce in response to consumer concern.
The only produce exempt from the ban are pre-cut or peeled potatoes that are used, for example, to make french fries or hash browns. Thus, potato products in delis and restaurants may still contain sulfites. (The exemption does not apply to whole potatoes presented to consumers in the raw state.) Fresh peeled potato producers have argued that suitable substitues for sulfites have not been discovered and that a ban would destroy their industry.
11. What are the sulfite labeling requirements for packaged foods?
Prior to January 9, 1987, only those sulfites involved in the processing of the final product, such as those used for preservation, had to be listed on a product label. Currently, however, labels must list any use of sulfites in preparation that leaves a detectable residue on the final product at least 10 parts per million (ppm). Current technology does not allow reliable detection of amounts below this threshold.
Consumers should check food labels for any of the following terms as indicators of sulfites: sulfur dioxide, sodium sulfite, sodium bisulfite, potassium bisulfite, sodium metabisulfite, potassium metabisulfite or the term "sulfiting agent."
Manufacturers who fail to list sulfites on product labels risk removal of their product from the marketplace. In 1986, FDA requested hundreds of recalls for products with labels that failed to disclose the presence of sulfites. Many of these were dried fruit and trail mixes.
USDA prohibits the use of sulfites on meat because these can restore the red color and thus create a false appearance of freshness. Ingredients treated with sulfites may be added to meat in the preparation of certain processed foods, such as beef stew. Therefore, the agency's Food Safety and Inspection Service (FSIS) on December 17, 1986, adopted a labeling policy for processed meat products consistent with FDA's regulation. FSIS requires ingredient statements to include either the specific name of the sulfiting agent or the term "sulfiting agent(s)" if the use of sulfited ingredients results in a level of 10 ppm or more in the finished product. Sulfites must also be declared if one part of a multi-component dinner, such as mashed potatoes, contains 10 ppm or more of sulfites, even if the entire dinner contains a lower level.
12. Are there any sulfite labeling requirements for alcoholic beverages?
Since July 9, 1987, warning labels have been required on all alcoholic beverages with at least 10 ppm of sulfites. Only beverages bottled prior to that date are exempt.
The warning appears on either the front or back label of the product or on a bottle neck strip. It contains a generic statement, such as "contains sulfites," or a specific statement as to the type of sulfiting agent involved.
13. Do drugs list sulfites on their labels?
FDA regulations that went into effect June 3, 1987, require manufacturers to include a warning label on all prescription drugs to which sulfites have been added. Sulfites need not be listed on the labels of over-the-counter products so sulfite-sensitive individuals should contact the manufacturer to determine whether sulfites are used in specific over-the-counter products.
14. Can sulfite residues in food be detected?
Because all sulfiting agents can produce sulfur dioxide, residues are measured as parts per million of this gas. These residues cannot be detected with the human eye.
FDA supports the use of a test known as the modified Monier-Williams method for measuring sulfite residues. The agency published a description of the procedure in the Federal Register along with its recent sulfite labeling regulation.* Less expensive, less time-consuming alternatives to the Monier-Williams method are being evaluated.
Despite the availability of sulfite strips, a commercial device designed to indicate the presence of sulfites, caution in their use has been urged by leading scientists in sulfite research at the Food Research Institute of the University of Wisconsin. They oppose use of the strips unless users are carefully instructed in the procedures and are provided a list of foods that could give false positive or negative results. An FDA advisory committee condemned the test strips, citing their "inherent errors and false negative determinations." Their inaccurate readings may confuse consumers.
15. On what foods are sulfites still being used?
Use of sulfites as a preservative is now limited to certain seafood products and a variety of processed foods, including peeled potato products. A list of food categories in which sulfites are sometimes used appears at the end of this paper. FDA advises sulfite-sensitive individuals to use this list only as a guideline and to read labels on processed foods carefully.
Sulfites also may still be used as a fungicide to prevent grey mold or bunch rot on domestic or imported grapes during shipment and storage. The long-term storage necessary to extend the availability of grapes often involves repeated sulfite treatement.
On December 31, 1986, EPA announced an interim policy regarding the use of sulfiting agents on grapes. The goal was to inform sulfite-sensitive individuals until a tolerance or other appropriate clearance could be established. The policy stated that sulfite residues on domestic or imported grapes must be below detectable levels (10 ppm) when the grapes entered the United States or were introduced into interstate commerce. Each shipper was required to have an FDA-approved certification program to ensure that sulfite residues were below 10 ppm. Any shipment not covered by certification or found to have sulfite residues in excess of 10 ppm would be deemed adulterated and subject to seizure or detention by FDA.
Because of the cost and logistical problems encountered by the California table grape industry, EPA amended its interim policy on August 26, 1987, to include alternatives to its existing certification requirements. The amendment permits grapes with sulfite residues above 10 ppm as long as the shipper 1) enters into a written agreement with the retail seller ensuring that placards are posted at the retail point of sale or 2) tags at least 40 percent of the individual bunches of treated grapes in a given box and the tags are retained at the retail point of sale. The placards or stem tags must state clearly and conspicuously that the "grapes have been treated with sulfites." An explanatory phrase, such as "to ensure freshness" or "to ensure quality," may follow the mandatory message. Any shipment of grapes with detectable residues that is not in compliance with the placarding or tagging program will be deemed adulterated and subject to enforcement action by FDA.
Most retailers have rejected the placard option, insisting that shippers bear the responsibility for identifying the sulfited grapes by attaching stem tags.
The amendments to the December 1986 policy went into effect on the date of their publication in the August 26, 1987, Federal Register. On January 5, 1989, EPA extended its interim policy regarding the use of sulfites on grapes until a tolerance for the residues on or in grapes is established. At the same time, EPA proposed to establish a tolerance standard at 10 ppm, the current level of detection.
FDA GUIDE TO FOODS AND DRUGS WITH SULFITES
The following foods and drugs may contain sulfites, according to the Food and Drug Administration. Not all manufacturers use sulfites in these products, and the amounts may vary. Remember to check the product label.
Food Category Type of Food
Alcoholic Beverages Beer, cocktail mixes, wine,
wine coolers.
Baked Goods Cookies, crackers, mixes with
dried fruits or vegetables,
pie crust, pizza crust, quiche
crust, flour tortillas.
Beverage Bases Dried citrus fruit beverage
mixes.
Condiments and Relishes Horseradish, onion and pickle
relishes, pickles, olives,
salad dressing mixes, wine
vinegar.
Confections and Frostings Brown, raw, powdered or white
sugar derived from sugar beets.
Modified Dairy Products Filled milk (a specially
prepared skim milk in which
vegetable oils, rather than
animal fats, are added to
increase its fat content).
Drugs Antiemetics (taken to prevent
nausea), cardiovascular drugs,
antibiotics, tranquilizers,
intravenous muscle relaxants,
analgesics (painkillers),
anesthetics, steroids and
nebulized bronchodilator
solutions (used for treatment
of asthma).
Fish and Shellfish Canned clams; fresh, frozen,
canned or dried shrimp; frozen
lobster; scallops; dried cod.
Fresh Fruit and Vegetables Sulfite use banned (except for
fresh potatoes).
Gelatins, Puddings Fruit fillings, flavored and
and Fillings unflavored gelatin, pectin
jelling agents.
Grain Products and Pastas Cornstarch, modified food
starch, spinach pasta, gravies,
hominy, breadings, batters,
noodle/rice mixes.
Jams and Jellies Jams and jellies.
Nuts and Nut Products Shredded coconut.
Food Category Type of Food
Plant Protein Products Soy protein.
Processed Fruits Canned, bottled or frozen fruit
juices (including lemon, lime,
grape and apple); dried fruit;
canned, bottled or frozen
dietetic fruit or fruit juices;
maraschino cherries and glazed
fruit.
Processed Vegetables Vegetable juice, canned
vegetables (including potatoes),
pickled vegetables (including
sauerkraut), dried vegetables,
instant mashed potatoes, frozen
potatoes and potato salad.
Snack Foods Dried fruit snacks, trail mixes,
filled crackers.
Soups and Soup Mixes Canned seafood soups, dried soup
mixes.
Sweet Sauces, Toppings Corn syrup, maple syrup, fruit
toppings, and Syrups high-fructose
corn syrup, pancake syrup.
Tea Instant tea, liquid tea
concentrates.
FREE daily e-mail newsletter for grocery retail executives.