On 25th October 2023, a 24-year-old youth named Rahul D Nair from Kochi, Kerala lost his life to food poisoning after allegedly eating shawarma ordered from a food joint in the city. The man who ordered shawarma on 18th October was undergoing treatment in a private hospital in Kochi. Rahul has been one of the many victims of food poisoning caused by shawarma and other Middle Eastern dishes including Al Fahm and Mandi. Experts opine that mayonnaise, a sauce used in Shawarma, is the key culprit in food poisoning.
A month before the incident, a 14-year-old girl from Namakkal, Tamil Nadu died of food poisoning after consuming shawarma from a restaurant. 43 others, including the girl’s family, who dined at the restaurant were taken ill and underwent treatment.
“The instances of shawarma-related food poisoning have been on the rise off late, with the mushrooming of eateries serving Arabic cuisine,” says Sakkeer Hussain, assistant commissioner of food safety, Kozhikode, Kerala.
Mayonnaise and food poisoning
Mayonnaise is an emulsion of raw eggs and vegetable oil. The thick creamy sauce serves as an ingredient as well as a popular side dish for several Arabic delicacies.
In the wake of the rise in shawarma-related fatalities, the Kerala government imposed a ban on the use of raw eggs in mayonnaise.
Harmful salmonella in raw eggs
“The risk of food poisoning is associated with locally made mayonnaise. Store-bought mayonnaise doesn’t pose harm,” says, Dr Rajeev Jayadevan, gastroenterologist and member, Public Health Advisory Panel, Kerala State Branch, Indian Medical Association.
“The eggshells get fecally contaminated, on coming in contact with bird droppings in the cage,” says Dr Rajeev.
Salmonella is a bacterium commonly present in animal and human intestines and released with feces. The eggshells get exposed to salmonella after coming in contact with fecal matter.
“The shell is rarely washed before the egg is used. When the egg is cracked, the contents of the egg tend to ooze over the surface of the egg, and the bacteria present on the surface can wash down into the bowl along with the contents of the egg,” explains Dr Rajeev.
It has also been observed that salmonella bacteria can penetrate the eggshells.
Dr Rajeev says that when mayo is locally made, there is no monitoring. So, the bacteria can stay alive in the medium.
Unlike bakery products like cake, cookies which are prepared in high temperatures, mayonnaise is uncooked, posing a risk of food poisoning.
Cooking eggs kills bacteria
Temperatures above 60 degree Celsius kill most bacteria. When raw eggs are used in preparing cakes, the high temperature kills the bacteria. One must refrain from eating uncooked cake batter or cookie dough.
Hussain recommends pasteurizing the eggs before use, to kill salmonella. Elaborating on the pasteurization process, he says, “Heat the eggs in warm water at 65 degrees Celsius for 3 to 5 minutes, and rinse the eggs with cold water, until the shell drops to room temperature.”
Lapses in storing mayonnaise
According to Hussain, a lapse in storage and handling of locally made or homemade mayonnaise can cause proliferation of the bacteria, leading to food poisoning. Bacterial growth depends heavily on temperature.
“When mayonnaise is stored at room temperature, which averages 28 to 35 degrees Celsius in India, it serves as an ideal breeding ground for bacteria,” says Hussain.
Hussain opines that mayonnaise shouldn’t be left at room temperature beyond 30 minutes.
“Bacteria when kept at room temperature multiplies at an exponential rate, which means that one cell divides into 2, then 4, then 8, 16, 32 and so on,” says Dr Rajeev.
He adds that the longer the product sits at room temperature, the more bacteria present in it, increasing the chances of the person getting infected.
Refrigeration of mayo is important
According to the United States Department of Agriculture, mayonnaise needs to be refrigerated and used within four days. It is not recommended to freeze mayonnaise, as it will separate and appear curdled after freezing.
Bacterial reproduction drops when the temperature is below 4 degrees C, refrigeration of mayo pauses the bacterial multiplication, reducing chances of food borne illnesses.
Who is at risk?
Not everyone who eats the same contaminated food gets food poisoning. Some people are more vulnerable than others.
“The possibility of a person getting infected, and the severity of the symptoms depends on their gut immunity,” says Dr Rajeev.
The amount of bacteria ingested also plays a role in the person getting infected. The more the amount consumed, the greater the chances of infection, notes Dr Rajeev.
“Symptoms include vomiting and diarrhea, which causes a loss of fluids and electrolytes. Loss of fluids without replacement can cause complications including organ failure,” says Dr Rajeev.
He advises seeking treatment including administration of IV fluids.
Meat: A high-risk food
Besides the mayo in shawarma, spoilt or undercooked meat can also give way to food borne illness.
Preparing shawarma involves slow-roasting meat slices stacked on a vertical spit and shaving off the cooked surface.
“Parts of the meat can remain undercooked,” says Hussain.
Besides, when the meat is stacked on the spit, there are chances of spoilage of the meat at the core, adds Hussain.
He recommends pre cooking the meat to kill the bacteria before the meat is stacked on the spit.
Hussain also stresses that meat needs to be refrigerated (at -5 degrees Celsius), and the exposure to room temperature should be minimal.
Takeaways
- The raw eggs in locally made mayonnaise pose a risk of food poisoning.
- Eggshells contain the bacteria salmonella which is responsible for food poisoning.
- Refrigeration of mayo pauses bacterial multiplication, reducing chances of food borne illnesses.
