How you eat is how you live.
Let's eat well together.
Sign up for our useful and inspiring emails.
Get a $10 credit at Provisions,
our new kitchen and home shop, launching soon!
Well played.
You deserve a cookie.
We'll email you about claiming your credit and earning more by inviting friends.
Or Claim Your Credit Now
There are some bacteria/ molds that grow at certain temperatures. The one that causes the most food spoilage occurs at the medium range of 68-113 Farenheit range. These bacteria are known as mesophiles. They have molds and bacteria that grows at even hotter temperatures or in your case, colder (psychophiles aka cold-lovers). Either that, or it is just a collection of unknown materia (could be from packaging dye scrapings) that collected on the ice. Hope that helps.
Molds won't grow below freezing but they can easily survive the process. With that in mind, possibilities include that the mold grew before you put the tortillas in the freezer, while they were cooling in the freezer, and after they were removed from the freezer. Mold could also have grown during repeated defrost cycles or because your freezer isn't working properly.
I'd say your freezer doesn't work properly. To check, put in ice cubes in a bag / box, and check them. Once they aren't cubes anymore your freezer (and its contents) thawed.