Generally speaking, the worst thing you can say about ice cream is that it melts. When it comes to an ice cream sandwich, however, the worst thing you can probably say is that sometimes it takes a freakishly long time to melt. 

Last month, an Australian woman named Mary Salter encountered this strange phenomenon and quickly assumed the worst about the reasons behind it. In a Facebook post, Salter explained that her grandson recently threw half an ice cream sandwich from the supermarket brand Coles on the ground outside. Four hot days later, she claimed, it was still intact. “Now I am a little concerned just WHAT is in this ‘treat,'" she wrote. Coles told an Australian reporter that the company uses “very simple, commonly-used food techniques that help slow the melting process.” But I'm always in the relentless pursuit of the truth, particularly when it comes to ice cream, so I decided to investigate further.

Should we be worried about everlasting ice cream sandwiches? The short answer is no, according to Cary P. Frye, the vice president of regulatory and scientific affairs at the International Dairy Foods Association. Frye is a food technologist, and she’s used her expertise to advise companies that make ice cream and other dairy-based delights.

“There is no reason to be concerned,” Frye told me, when I called her mid-freak out. “If you have one ice cream sandwich that melts quickly and another that melts slowly, they may have different ingredients but they’re the exact same safety level.”

Why do some ice cream sandwiches melt so slowly, then? According to Frye, the answer has to do with the product’s two delicious yet inherently incompatible elements. “You have hard cookies and soft ice cream. When they’re formulating the product the goal is to be able to eat them together so you can crunch down on the cookie and not have the ice cream squirt out on your summer dress or shirt,” she said. The ice cream, therefore, has to stay solid to maintain the whole structure’s integrity. If the ice cream melts too quickly, the result is basically sandwich anarchy.

Manufacturers keep things in order by adding a few crucial stabilizing and emulsifying ingredients to the ice cream. There are gums made from beans and seaweed, and some that are made from chemicals. Emulsifiers can be made with vegetable fat or egg yolks. Manufacturers also tinker with the amounts of certain key ingredients to slow melting. More cream, more sugar and less fat in the ice cream make for a longer-lasting sandwich.

Unfortunately, these well-intentioned innovations can have the unintended effect of freaking customers out, especially if a sandwich’s melt time is uniquely prolonged. In 2014, Cincinnati television station WCPO checked out Walmart’s Great Value ice cream sandwich after a viewer reported that one she bought lasted 12 hours outside in the sun. Indeed, when WCPO tested it, the Walmart sandwich barely melted after 30 minutes, while similar products from Häagen-Dazs and Klondike turned into soup. While that may seem suspicious to many consumers, Snopes reported that all of the ingredients in the Great Value sandwich “have been deemed safe for consumption by the FDA.” The same can be said for other sandwiches with comparable longevity.

Frye hasn’t had a look at the Coles sandwich in question, but she said if indeed it lasted four days without melting, “that would be on the extreme end of the meltability spectrum.” That isn’t bad, she said, but she said it’s worth emphasizing that consumers should by no means eat an ice cream sandwich that has been exposed to the elements for four days.

“You would never want to eat something that’s been left out for even a day because of bacteria spoilage with dairy products,” she said.