Some of the very people who have been using sulfites to keep salad bar ingredients green and crisp now say the preservative should be banned.

In testimony Thursday before an ad hoc panel of the Federation of American Societies for Experimental Biology (FASEB), the National Restaurant Association (NRA), in conjunction with the Produce Marketing Association, called for a ban on the uses of sulfites for salad ingredients and pre-cut potatoes.

FASEB has been commissioned by the Food and Drug Administration to review the scientific literature on sulfites and to help reexamine its status on the Generally Recognized as Safe (GRAS) list. The purpose of Thursday's public meeting was to gather responses to a tentative report issued this October by FASEB, in which the scientific group concluded that sulfites may cause "acute allergic-type" reactions in certain individuals, particularly asthmatics.

The FDA estimates that about 5 percent of the nation's asthmatics, or 450,000 individuals, may be hypersensitive to the preservative. The agency is presently investigating 300 reports of consumer complaints associated with the consumption of sulfites, as well as four reports of death linked with consumption of the preservative in restaurants.

The proposed NRA and PMA ban calls for the elimination of those uses of sulfites that have most often been linked with allergic reactions, said the NRA. Salad ingredients and pre-cut potatoes, according the trade association, fall into that category. In addition, the ban proposes that the compounds be abolished at both the retail and wholesale levels.

NRA is proposing the ban even though according to Jeff Prince, spokesman for the association, less than 3 percent of its 10,000 members are actually still using sulfites. The preservative may, however, already be present in foods restaurateurs purchase from suppliers, says NRA, although according to the Produce Marketing Association, an informal survey of 57 of its members who distribute fresh produce to food service operations showed that 95 percent of the firms no longer use the preservative either.

Some members of both associations have instead pursued two alternatives -- they either use nothing to preserve salad items (at the restaurant level, they are instead slicing foods more frequently) or are using ascorbic acid-based preservatives.

However, despite efforts to convince consumers that the association's members no longer use sodium bisulfites, "there remains a lingering doubt that salad bars are somehow tainted," wrote Steven N. Ahlberg, staff vice president of the PMA, in a letter to the NRA in endorsement of the ban. A ban "would be the decisive step necessary to restore consumers' confidence in the safety of fresh fruits and vegetables consumed away from home," Ahlberg worte.

In addition, a ban of sulfites on salad bar ingredients and pre-cut potatoes would override the FASEB report's recommendation that foods containing sulfitess be labeled as such. The trade association has also raised this objection with the FDA, which is presently considering a labeling proposal.

The NRA contends that sulfite labeling is an ineffective and confusing answer to the problem. "Labels on menus and signs in restaurants could unnecessarily frighten those patrons who have no reason for concern, supply insufficient and incomplete information to those members of the population who should be concerned and offer no protection to those asthmatics who are unaware of their sulfite-sensitivity," said James T. Rogers of the NRA, reading the testimony of the association's executive vice president, William P. Fisher at Thursday's meeting.

In addition, there are no "neat" channels of food service distribution that would ensure consistent and accurate labeling of sulfite-containing products from manufacturer to the retail level, said Rogers. Restaurateurs rely on a diversity of supply sources, he said. "How do you label six heads of lettuce or other raw produce products purchased at a farmer's market?"

Sanford Miller, director of the FDA's Center for Food Safety and Applied Nutrition, said he is "sympathetic" about the restaurateur's dilemma when it comes to sulfite labeling, but that NRA's ban proposal on specific uses of the preservative creates complex legal difficulties for the agency. "We're working towards a situation where we can legally alleviate what we think is the most important usage of sulfites ," said Miller. Labeling, he added, is an approach that can be done in the interim, although it "is not the end," Miller said.

Michael Jacobson, director of the Center for Science in the Public Interest, commended the NRA and PMA for their proposed ban, adding that it is "rare" that industry groups "take this stand." Jacobson, who also testified at the meeting, agreed with the associations that sulfite labeling "cannot adequately protect the public." CSPI is urging the FDA to ban all unnecessary uses of sulfites.

Although Miller of the FDA said salad bars constituted the highest exposure to sulfites, their ingredients are by no means the only foods that contain the preservative. Among processed foods, sulfites are found in wines, beer, dried fruits, soups and salad dressings.

Both the National Food Processors Association and the Grocery Manufacturers of America testified at the meeting, stating that there is no evidence to date to suggest that sulfiting agents in processed foods demonstrate a hazard to the general public. Both associations agree with the FASEB report, however, that additional studies need to be done.

The NRA's Prince said the association doesn't see its proposed ban as the ultimate solution to the sulfite situation, but in the meantime "we don't want to risk customers getting ill in our restaurants." He said the ban is a way to reduce the problem until the necessary research can be done.

The NRA, in conjunction with the American College of Allergists, is distributing a leaflet that gives dining-out tips to sulfite-hypersensitive individuals. A copy of the leaflet can be obtained by sending a self-addressed stamped envelope to the National Restaurant Association, Communications Dept., 311 First St. NW, Washington D.C. 20001.