Always thought freezing kilt everything.
The Chilling Reality Of Listeria Contamination In Frozen Foods
It’s easy to understand the importance of washing fresh produce and following standard kitchen safety rules when cooking with raw meat, but we don’t typically think of frozen foods as hotbeds for bacterial contamination. Recent studies, however, have shown that listeria bacteria have the ability to live on frozen foods — including vegetables and hot dogs — during long-term storage. Listeria is a genus of bacteria, and Listeria monocytogenes is a particularly harmful pathogen described by the Food and Drug Administration as “a type of disease-causing bacteria that can be found in many places, including soil, water, sewage, rotting vegetation, and animals.”
Freezing food doesn’t kill most bacteria on it, but doing so can hinder bacteria from multiplying. What makes listeria so dangerous is its ability to multiply in temperatures exceeding 0 degrees Fahrenheit (the average home freezer temperature). The bacteria can spread through water, dirt, and even open air, making it easy for contamination to occur during food processing. Symptoms of non-invasive listeriosis (listeria infection) include gastrointestinal symptoms, muscle aches, and fever. Invasive listeriosis is far more serious and can cause convulsions and death, especially in vulnerable populations.
I did not know 0 was not cold enough.
0 degrees does stop it:
https://content.ces.ncsu.edu/listeria
https://ask.usda.gov/s/article/Can-Listeria-grow-at-refrigerator-temperatures