Rangsiya Sara-uppatham, a 34-year-old Chon Buri resident, on May 31 posted photos of the eggs that were bought from a Tesco Lotus store and which turned into something that looked like worms when being boiled.
A day later, Tesco Lotus and the Department of Disease Control took the eggs for a lab test.
Dr Taweesak Songserm, from the Faculty of Veterinary Medicine at Kasetsart University, said worms cannot normally enter eggs due to their hard shells.
The strange texture was caused by the high quantity of bacteria that changed the property of the eggs and resulted in a worm-like appearance, he added.