Jell-O products were removed today from grocery shelves in at least six states, including stores in Detroit, Chicago and Atlanta, after a second day of telephoned threats of tampering.

In addition, officials in the New York metropolitan area were removing 2-liter bottles of lemon-lime Slice from stores after someone claimed to have put cyanide in five bottles of soda.

Federal and state law enforcement authorities were investigating the incidents, and as of tonight no illnesses or evidence of poisoning or tampering had been reported.

But as Dean Schott of the Illinois Department of Public Health said, "We have to take these telephone threats seriously," and the official response was swift. Thousands of boxes of Jell-O dessert, pudding and gelatin mix were pulled from grocery shelves until answers can be found in this latest episode of product-contamination threats.

Store officials said the Jell-O products likely will be returned to the manufacturer, General Foods, for inspection by the Food and Drug Administration.

The first Jell-O threat was phoned in Thursday to General Foods' consumer hotline. An unidentified man warned that cyanide had been put in two boxes of sugar-free Jell-O Gelatin in Jewel Food Stores in the Chicago area, and in one box in a Kroger store in the Detroit area.

"Better take this seriously, this is no joke," the caller warned.

This morning, an anonymous male caller to General Foods -- authorities could not say whether it was the same person -- said that four boxes of Jell-O instant chocolate pudding mix had been "contaminated" in a Dominick's food store in the Chicago area.

"We don't know whether this is a copycat case or not," a spokesman at the FBI's Chicago field office said.

The call prompted General Foods to order the removal of all Jell-O dry-mix dessert products from Chicago-area store shelves.

A spokesman for Jewel said the supermarket chain ordered all Jell-O products removed from its 218 stores in Illinois, Indiana, Michigan and Iowa after learning of the second threat.

Kroger spokesmen said Jell-O products were pulled from shelves in 57 of the company's Detroit-area markets and nine in Atlanta.

Other food chains carried out similar removals. In Quincy, Mass., Jell-O desserts were pulled from a Stop & Shop store after a threat was received, a General Foods spokeswoman said.

In the New York incident, a anonymous caller to the police emergency line said that cyanide had been put in five bottles of a Pepsi product. The lot number the caller gave was nonexistent, but Pepsi-Cola officials decided to recall the lot number most closely resembling it.

A spokesman for Pepsi-Cola Bottling Co. said that lot, 6F18B23-82, consisted of 11,500 cases of Slice drink that had been distributed in New York's five boroughs and suburban Westchester County.

Charles Thomas, president of the bottling company, said that 4,000 cases from the lot had been distributed June 18, and that most of it had probably been consumed, wire services reported. The remaining 7,500 cases were located in a warehouse in Queens.

The incidents are the latest in a wave of product-tampering cases that has swept the nation in the aftermath of the Tylenol cyanide poisonings of seven people in the Chicago area in 1982.

"It's the new terrorism," one Illinois public health official said today.

The Tylenol killer was never caught. To prevent a recurrence, manufacturers turned to tamper-resistant packaging, but the threats have not abated. Most of them have been directed at over-the-counter capsule drugs, but other products -- ranging from baby food to Girl Scout cookies to pickles -- also have been targeted.

Six people have died in the United States this year from cyanide poisioning involving capsule medications, including three suspected suicides. Two of the deaths occurred in Auburn, Wash., where a ban on capsule sales continues although Mayor Bob Roegner lifted his state of civil emergency today, according to wire service accounts