I'm not sure if this topic goes with the Food Microbiology category. But right I'm out of ideas, so any input would be very appreciated.
I work in a plant where frozen breaded poultry products are produce with no vacuum package. A couple of months ago, we starting receiving complaints about blown package from several customers. That is a first for me, I would not expect this kind of spoilage in a frozen product.
The product is not sensory altered, it doesn't seem like it was thawed (I can't be 100% sure about this), but usually when the product is thawed the breaded coating starts to detached. No off-flavor, off-smells...nothing. But my gut keeps telling me that this is related to temperature abuse.
The package has no micro-perforations.
We have tested some swollen packages and lactic acid bacteria and psychotropic counts are under 4 log10. Is there any chance this could be microbiological? Should we test for other indicator?
Any other probable cause for swollen package spoilage in frozen products?