The coroner in the case of the Canadian teenager who was initially thought to have died from a peanut allergy after kissing a boyfriend, says lack of oxygen to the brain was the most likely cause of her death.
The boyfriend who had just eaten peanut butter, was at first thought to have inadvertently caused a severe allergic reaction, resulting in the girls death.
But it now appears that Christina Desforges, 15, suffered from a lack of oxygen to the brain, which caused serious damage.
It is believed Desforges had asthma and was suffering from an asthma attack before she collapsed and died in a Quebec hospital in November.
Officials at the time said that doctors were unable to treat her allergic reaction to a kiss from her boyfriend the previous weekend.
But now it seems peanut butter was not the cause of Desforges' death and claims that injections used to treat allergic reactions were ineffective, were in fact incorrect.
The coroner said the girl and her boyfriend had kissed, many hours after he ate peanut butter and he had also eaten popcorn and drunk beer, generating saliva that would have cleansed his mouth before the kiss.
But according to a study released this week people with peanut allergies should be careful about kissing partners who have eaten peanuts or peanut butter.
The study looked at how much peanut allergen remained in saliva following a meal, and as a result of their findings people with peanut allergies are now advised to make sure their partners brush their teeth and then wait a number of hours before kissing, especially if the kissing is going to be passionate.
The new study involved 10 people and found that the peanut allergen was detectable in a majority of subjects after eating but left the saliva after several hours.
According to Dr. Jennifer Maloney of Mount Sinai Medical Center in New York, a member of the study team, a significant number of people with food allergies have significant reactions from kissing, especially "passionate kissing".
Maloney says cleaning the teeth or rinsing after eating and chewing gum did not immediately result in undetectable allergen levels, and won't necessarily make patients safe.
The study was presented at the American Academy of Allergy, Asthma and Immunology's annual meeting in Miami Beach.