'Tis Halloween, time to screen the children's trick-or-treat apples for the hidden razor blade or pin. Time to test the candy for the disguised drugs, the planted poisons.

But wait!Here comes Jan Harold Brunvand, America's most famous chronicler of modern legends, to tell us that our fear of killer candies is way out of proportion to the facts.

"Statistics," he says, "suggest that the kind of nasty-neighbor story that incites such fear at Halloween time is just another urban legend.

"The existence of large-scale threats to children from Halloween sadists is taken for granted by most parents," Brunvand wrote in his most recent book of stories in need of debunking, "Curses! Broiled Again!" "But this belief, and the fear that results, is based largely on hearsay and exaggerated reporting, not on documented attacks on children."

Brunvand cites a study, published in Psychology Today in 1985, which examined 76 incidents of treat-tampering reported between 1958 and 1984 in four major newspapers. Many turned out to be unverified reports or hoaxes invented by children in the spirit of Halloween mischief, Brunvand says. Not one report described an incident in which adulterated goodies from a stranger caused death or serious injury.

There were 20 cases of injury - all minor, the study said. There were two deaths. One child died after eating heroin hidden in candy at his uncle's house. Another was poisoned by his father, who put cyanide in his candy to make it look like the work of a Halloween sadist.

Yet stories of lethal trick-or-treats get wide circulation year after year. Newsweek went so far as to write in 1975: "Several children have died and hundreds have narrowly escaped injury from razor blades, sewing needles and shards of glass purposefully put into their goodies by adults."

Brunvand, a professor of English at the University of Utah and one of the nation's leading folklorists, commented on his work while attending the 100th annual meeting of the American Folklore Society in Philadelphia. He says the Halloween phenomenon is really just a form of present-day legend-making.

"These rumors and stories combine two familiar themes of urban legends: dangers to children and the contamination of foods," Brunvand notes.

Particulars of the reports change from telling to telling. But the razor blade and the apple regularly appear - possibly, the professor says, because of the apple's biblical status as a forbidden fruit.

"Mostly, however, the Halloween-sadist rumors seem to combine the fears that we naturally associate with the holiday," Brunvand says, "a fear of strangers, a fear of the night and fear for our children's welfare that is wholly justified, considering the myriad types of mischief that are given license on Halloween."

Despite exaggerated notions of Halloween sadists, Brunvand says it is still a good idea for parents to warn children about the hazards of taking candy from strangers and of eating it without inspection. "After all," he says, "urban legends often give good advice in a fictional framework."