American consumers forgot about the Chilean grape poisoning last year almost as soon as the U.S. government announced it was again safe to eat the fruit. But in Chile, the bad taste of the cyanide scare lingers.

How could the U.S. Food and Drug Administration, acting on an anonymous threat, have found two poisoned grapes among 6 million cases of fruit after searching for less than a day? In the minds of more and more Chileans, the answer is that the FDA botched the grape tests and Chile lost millions of dollars in fruit sales as a result.

A few Chileans have reached a more sinister conclusion: that the U.S. government concocted the scare to intimidate Augusto Pinochet, then Chile's dictator, and remind him how dependent he was on the United States.

The General Accounting Office is investigating the FDA's conduct in the Chilean grape incident. But the Chilean Exporters Association did its own probe. The exporters concluded, based on research done at labs including one at the University of California at Davis, that someone accidentally or deliberately injected the grapes with cyanide at an FDA lab in Philadelphia.

The exporters do not explain why someone might have done that, but Arturo Claro, senior partner in Chile's oldest law firm, has threatened to sue the U.S. government, claiming the grape incident was sabotage. Claro says that more than a year before the poisoning, a U.S. diplomat asked him what effect it might have if the United States banned Chilean fruit imports as a way to force Pinochet out of power.

"There is an ambassador of a Third World country who will testify against the United States. You will see soon," Claro told our associate Melinda Maas.

The U.S. Embassy in Santiago says Claro's charges are "absurd."

If the fruit was spiked in Chile, then the FDA was either very skillful or very lucky in the resulting investigation.

In early March 1989, the U.S. Embassy in Santiago and a Chilean export company got several anonymous phone calls warning that some Chilean fruit would be poisoned with cyanide. On March 11, a load of fruit arrived in Philadelphia from Chile and sat on the dock overnight. At 10 a.m. on March 12, FDA inspectors confiscated three grapes from the load and on March 13, the FDA announced an embargo on all Chilean fruit, saying two grapes had cyanide in them.

The Chilean Exporters Association now asserts that the temporary ban cost the Chilean fruit industry more than $300 million. The exporters say that, based on their studies, it would have been impossible to inject the amount of cyanide the FDA says it found in the two grapes, ship them to the United States and still have them arrive looking as fresh as they do in the FDA photos. The cyanide would have destroyed the grapes in a matter of hours and also would have affected the surrounding bunch, the exporters' research concluded.

"All of the evidence found shows that the grapes must have been contaminated either accidentally or intentionally in the FDA lab," David Holzworth, the Washington lawyer for the exporters, told us.

FDA officials say they are puzzled by the findings and refuse to believe the grapes were contaminated by someone in the lab.