We have 10 freezers on site, 9/10 are Conex type reefer trailers that are running 24/7, and are never turned off. They are all wired to temperature probes that come inside the facility that have low temp audible alarms tied into them, that will alert if they go above freezing, at all. Constant beep that can be heard from a good distance away.
The 10th freezer is a 2000sqft walk in type freezer, that is wired with the same alarm set up.
Then we have a cooler to store yeast in, that is wired the same, but settings are different.
So, it seems that the easiest way to go about this, is to do my research and write into my policy that even with a failure, given normal temperatures form the previous 24 hours, the frozen/refrigerated products are good up to a certain point without checking on them. I'll start looking into some research and see if I can dig up anything verifying that they will hold temps for X amount of time.