I made some liver wurst using pork. I did not cook the pork beforehand but sous vided it for 4 hours at 180° in glass containers.
Will this be enough to prevent my product from going bad if I keep it on the shelf without refrigeration, or do I need to freeze or refrigerate it?
Oooh. Boy. Lots of warning bells going off here.
Most meat products that are stored at ambient temperatures are heavily laden with preservatives.
Your liverwurst will require refrigeration.
Whether or not the product received enough time at temperaure depends on the dimensions of the product within the jar, the density (which impacts heat absorption) and to a much lesser degree the thickness of the jar. For that it would be best to refer to Baldwin.
http://www.douglasbaldwin.com/sous-vide.html
For the storage life, assuming proper pasteurisation, that will depend on your fridge temperatures. There is a table in Baldwin that gives safe shelf life of pasteurised product at various temperatures.
Pasteurization (to enable storage at ambient temperatures for very long times) depends on both the maximum temperature reached AND the time at which it is held there - in general, the longer the time at max temperature, the lower the max temperature that will Pasteurize. But there is a limit on how low the max temperature can be, no matter how long the temperature is held there and all of this varies between different foods. (It also varies with pressure, but with sous vide it’s all at atmospheric pressure. Which means you’d have to make adjustments for high altitudes.)
The only way to be sure is to consult an authoritative source and use a margin of safety.
Also note that the degree of risk from falling just below pasteurization conditions varies considerably between different foods.
Bottom line here, IMHO, is that the less you know, the higher the margin of safety you should maintain. (This is why some just nuke everything to death. They may not know much, but at least they are aware of the limitations of their knowledge.)
The three critical factors to take into account are:
maximum temperature attained
the time period for which that temperature is maintained
and the pressure under which the temperature is maintained.
If something isn’t heated enough to pasteurize it, then there are two major factors that determine how long it will store in the fridge (varys with each food, of course):
what the storage temperature is
and how long it takes to get down to that temperature.
For example, I put things like pots of soup into a water bath immediately once they’ve cooked sufficiently to cool them down quicker so they will store a lot longer. Commercial dairlys milking equipment automatically chills the milk immediately as it is collected so it is in much better quality when it reaches the consumer.
So a big advantage of sous vide cooking that I’ve not yet seen mentioned yet is that, because the maximum temperature is less, it can be cooled down faster which means it can be stored longer in the fridge. Of course freezing is better (and you can reheat it in the sous vide) but the quality when frozen also holds up better for longer when it’s cooled faster.
The wording here is a little bass ackwards, but you did correct yourself later.
Given that the time and the temperature have already been set, 4 hours at 180F (82.2C) the question still remains: was it at temperature long enough to achieve pasteurisation? The variables that will answer that were mentioned earlier, the dimensions of the product in the jar.
Assuming proper pasteurisation and rapid chilling through the danger zone for botulinum growth, safe storage times are as follows:-
Regardless of whether pasteurisation was achieved or not, I would not recommend storing this product at ambient (household) temperatures.
@Abe, Baldwin is the best introductory source for someone exploring sous vide processing. His work has been used by many government food safety authorities when formulating their safe handling requirements for commercial sous vide processing.