We are in the process of trying to introduce a new RTE Chicken Breast into our product line. It is vacuum packaged, and HPP'd (the cooking+vacuum packaging are contracted out to one company, the HPP out to a second company, after which it is returned to us for final packaging in a cardboard sleeve).
We received the fully processed product, however we were still working out kinks in our process flow and outer packaging and during this time the product was on QA hold. We were performing a confirmatory Shelf Life Study (based off of a "Best By" date provided by our contractors, with our QA department sending samples out once a week). The first four samples looked great, however the next two subsequent samples that we tested had extremely high APC counts (one at 10^7) and one had a coliform count of 2900. All previous samples had counts of 10 or <10.
Per our agreement with our HPP contractor, any breached packages were to be disposed of prior to shipping, and a "leaker rate" provided with each shipment. The leaker rate they provided was 0.0%, so I was very surprised to get such high counts after just 4 weeks of storage. Additionally, one of our shipping and receiving employees provided me with a package that had busted clean open (!!), presumably during storage of the product. None of the packages that we sent out for testing appeared to be breached in any way, at least to the naked eye. We subsequently sent out another sample which came back fine, and then 10 additional samples collected randomly, none of which appeared to have compromised packaging, yet 2/10 of the samples came back with high APC counts (>2500000 and 120,000).
Samples have also been tested for various pathogens (listeria, e. coli, salmonella, staph), all of which have come back negative, so I am guessing that the high counts are due to spoilage micro, though we have not had an opportunity to go too much into detail as to the type.
My questions are, has anyone ever had issues with breached packaging of an HPP product that was not detectable with the naked eye? Is a 0% leaker rate plausible? Obviously we cannot use the product but i'm trying to figure out where the breakdown happened, and who is ultimately responsible - the company who vacuum packed, or the company that HPP processed? Or are we storing it in a manner that would lead to the packaging being damaged??
any insight would be greatly appreciated!