Peanuts were once a stock-in-trade for airlines but finding them is getting harder with Korean Air the latest to join a growing list of carriers no longer serving the snack. Korean came under fire after it offloaded two teenage brothers on a flight from South Korea to the Philippines because of one of them was severely allergic to peanuts. The boys, whose father was temporarily based in Manila, had been visiting their sick grandfather in Atlanta. They had informed Delta Air Lines, which handled the first leg of the flight, of the allergy. They were offloaded from Delta partner Korean when they revealed the condition to staff. The incident prompted Korean to revisit its policy on the peanuts and it announced Monday decided to replace the snack with crackers in order to provide "a safe environment for all passengers" and prevent similar problems. READ: Passengers happier when they can track their baggage. It will also remove food containing peanut ingredients from in-flight meals. "The decision to stop peanut products and peanut ingredients is the minimum safety measure for peanut-allergy passengers," a Korean Air spokesperson said. The emergence of passengers with severe allergies that can cause life-threatening symptoms has prompted other airlines to look at the peanut question including a long time champion of the snack, Southwest Airlines. Southwest stopped serving peanuts on August 1, 2018, and replaced them with pretzels. "Peanuts forever will be part of Southwest’s history and DNA," the airline said at the time. "However, to ensure the best onboard experience for everyone, especially for customers with peanut-related allergies, we’ve made the difficult decision to discontinue serving peanuts on all flights beginning Aug. 1." Other airlines that no longer serve peanuts as snacks include American Airlines, Air Canada, Aer Lingus, Lufthansa, Qantas and United Airlines,  while Delta Air Lines will not serve them on a flight where a passenger notifies it of an allergy. A comparison of airlines is available at Allergy and Anaphylaxis Australia. All airlines warn that they cannot guarantee an allergen-free environment, or that people won’t bring on board their own nuts,  and several suggest that allergy sufferers bring EpiPens with them. American allows customers with peanut allergies to board first, giving them a chance to wipe down their seat and avoid contact with any residue left by previous passengers. One airline suggests customers with allergies fly on early morning flights shortly after aircraft have been cleaned.