Product tampering in order to kill or harm people has a long history.

Cases now under investigation involving needles in airline meals on Air Canada and Delta Air Lines have once again brought the focus on this frightening crime.

Here's a list of five of the more sensational cases, beginning with one from the 19th century.

1. Bromo-Seltzer, U.S.A., 1899

It was not the first product tampering case of its era but it's certainly the most famous.

On Christmas Eve, 1898, Harry Cornish, the director of New York's Knickerbocker Athletic Club received a package at the club. Inside were a silver bottle holder and a Bromo-Seltzer bottle.

There was also a small gift envelope but with no card inside. Cornish thought it was a playful hint to avoid excessive drinking over the holidays.

He took the bottle holder and the bottle home. A few nights later, a relative of Cornish's, who had admired the bottle holder, awoke with a headache. Katherine Adams took some of the Bromo-Seltzer, which she said tasted bitter. Then Cornish also took a sip.

The drink's bitter taste resulted from something that had been added to the Bromo-Seltzer: cyanide. (See sidebar).

An hour later, Adams was dead. Although sickened, Cornish survived. In November, another club member, Henry Barnet, had died under similar circumstances.

New York newspapers were all over the story. The police investigation soon centred on a former club member and chemist, Roland Molineux, who had feuded with Cornish and had been Barnet's romantic rival.

The 1899-1900 trial was one of the longest in New York history at that time. Molineaux was found guilty of Adams' murder.

He appealed and won a new trial because of evidentiary error. The prosecution had linked Molineux to Barnet's death even though he was not charged.

The Court of Appeals ruling was a landmark in U.S. law because it established that the presumption of innocence means that previous crimes cannot be used as evidence in an unrelated case.

In the second trial, the jury took just 12 minutes to deliberate. Molineux was found not guilty.

Today, in New York state when there's a pre-trial hearing on the admissibility of evidence, it's called a Molineux hearing.

2. Tylenol, U.S.A., 1982

It was the case that changed the way drugs are packaged and led to new product tampering laws.

Seven people in the Chicago area died in 1982 and another woman died in New York state in 1986 after taking cyanide-laced Tylenol. The case has not been solved. (Mark Blinch/Reuters)

Seven people died in the Chicago area after taking extra-strength Tylenol that had been laced with cyanide.

And it remains one of the biggest unsolved murder cases in the U.S., a case that has had more than 100 police investigators, more than 6,500 leads and 400 possible suspects.

But there's no known crime scene and no known motive.

Tylenol was recalled and its market share plummeted, but after a few years it was the No. 1 analgesic in the U.S.

James W. Lewis was charged in the case but only with extortion. Lewis, a former tax consultant, had moved from Chicago to New York in September 1982. (The murders happened at the end of September and Oct. 1.)

Lewis had sent a letter to Tylenol's manufacturer, a subsidiary of Johnson & Johnson, demanding $1 million "to stop the killing." Lewis served 11 years in prison.

In the months following the Tylenol murders, there were 270 cases of suspected product tampering in the U.S.

Tylenol began using tamper-resistant packaging. Nevertheless, in February 1986 in New York state, Diane Elsroth died after taking cyanide-laced Tylenol. That case, too, has not been solved.

3. Oronamin C, Japan, 1985

About 12 people died in Japan in 1985 after consuming paraquat-laced drinks from vending machines, which are ubiquitous in Japan. (Toru Hanai/Reuters)

Beginning in April 1985, people in Japan began dying after consuming popular drinks that usually appeared to be dispensed from vending machines.

The death toll across Japan may be as high as 12, making the so-called "vending machine murders" possibly the deadliest product-tampering case in history. Many more people became seriously ill.

The most-frequently tampered drink was Oronamin C, an energy drink with added vitamins. It sells in the billions every year.

The drinks had been laced with paraquat, an herbicide. At the time, vending machines would sometimes give out two drinks as a marketing ploy.

Police suspected that the killer usually left the poison drink in the machines' dispenser slot. Police also speculated that some of the deaths might have been suicides or the work of copycat killers.

The case remains unsolved. Japanese broadcaster NHK and CBC News were unable to find any reports of an arrest in the case.

In 1998, Japan had another wave of poisonings of drinks sold in vending machines and convenience stores.

4. Excedrin, U.S.A., 1986

Oronamin-C, advertised above, a very popular energy drink in Japan, was the most common target in the 1985 vending machine tampering deaths.

In Washington state in 1986, two people died after taking cyanide-laced Excedrin.

Bruce Nickell was the first to die, a result of emphysema, physicians said.

Then Susan Snow died after taking extra-strength Excedrin.

Bristol-Myers instituted a nationwide recall of Excedrin. Nickell's wife, Stella, then came forward with the information that her husband had also taken Excedrin, which turned out to have the same lot number. She filed a wrongful death lawsuit against Bristol-Myers, as did Snow's husband.

Cyanide-laced Anacin was also discovered on the shelf in a third area store.

An indictment finally came in December 1987. The person responsible for tampering with all three bottles was Stella Nickell.

She killed her husband in order to collect on the insurance. The other two bottles — and Snow's death — were a result of her efforts to cover her tracks.

Nickell is currently serving a 90-year sentence.

Her conviction and sentence were the first to follow the product tampering laws passed after the Tylenol murders.

5. Sudafed, U.S.A., 1991

Kathleen Daneker and Stanley McWhorter died in Washington state after taking cyanide-laced Sudafed, a decongestant.

Burroughs Wellcome & Co., Sudafed's manufacturer, recalled the product from across the U.S.

Three other tampered bottles of Sudafed were found on store shelves.

But there was, in fact, a sixth bottle of cyanide-laced Sudafed.

On Feb. 2, 1991, before the deaths, Jennifer Meling took a Sudafed that her husband, Joseph, had given her, to stop her snoring.

Soon after she became unconscious, Joseph called 911, and Jennifer was rushed to hospital. She survived.

In August 1992, police arrested Joseph Meling after determining that he had purchased sodium cyanide weeks before the poisonings, using a false name.

According to the prosecution, Meling's motive had been to collect insurance money for his wife's death and, worried he would be a suspect in the poisoning, he planted the other five bottles to deflect suspicion.

Meling was convicted and sentenced to life in prison.