Amtrak ordered the removal of all "nitrogen packaged" sandwiches from its trains and commissaries yesterday, and immediately stopped sales of the sandwiches in response to "widespread negative news stories" warning of possible health dangers associated with the packaging process.

It was reported in yesterday's Washington Post that several Food and Drug Administration investigators had become concerned about the possibility that the nitrogen packaging process could expose the sandwiches to possible botulism toxins.

The packaging process involves the removal of virtually all air from the sandwich package, followed by the injection of pure nitrogen into the package. It is designed to keep the sandwiches fresh longer.

But internal FDA memos obtained by The Washington Post showed concern within the agency over the fact that the oxygen-free atmosphere created in the package could also fuel the growth of C. Botulinum (botulism).

The FDA investigators working on the case said that under ideal conditions, with proper refrigeration, there appeared to be no problems with the sandwiches. But, according to the memos, at least three FDA field investigators were concerned that Amtrak's equipment was not adequate, and if the sandwiches were left unrefrigerated for long periods, the threat of botulism spreading would be greatly increased.

FDA officials acknowledged yesterday that they are conducting two investigations concerning the sandwiches. The first - beginning Monday - is a test of the sandwiches themselves, in an attempt to see how easily botulism can spread in the sealed sandwich's environment. The second is an investigation into Amtrak's equipment to determine the danger of equipment failure that could lead to underrefrigeration.

FDA spokesman Wayne Pines confirmed an earlier report that the agency did not officially notify the sandwich producer, American Micro-Fare, a Dallas-based firm owned by Dallas Cowboy's owner Clint Murchison, that the FDA above and beyond those conducted by the company earlier for the FDA.

Pines said, however, that the FDA was not "about to take regulatory action . . . our investigation is continuing. Had Amtrak continued to sell the sandwiches, we would not have ordered them to stop."

The Amtrak recall yesterday involved some 96,000 sandwiches which cost the railroad $76,800. Because of its contractual agreement, Amtrak probably will abosrb the costs, although American Micro-Fare president Frank Creager said he expects to "work with Amtrak."

"We think highly of Amtrak people," Creager said in a telephone interview, "and we will do what we can to continue working with them. For now, we have the ability to package without nitrogen merely by turning off two valves, although we think the nitrogen system provides a far superior product."

Amtrak officials began calling regional distributors yesterday and placing rush orders for regularly packaged sandwiches to be delivered as early as 2 p.m.