Some of the “food safety” concerns may be exacerbated by or minimized by the type of food you are intending to cook. For example, if you are cutting your own steaks from a primal cut of beef, the likelihood of intoxication is minimized because the interior meat is unlikely to have been contaminated by anything like A. botulinum or E.coli unless it happens to be thriving in your kitchen . . . in which case you must be immune. Grinding your own beef from whole muscle meat – same thing. If you are slicing/processing and vacuum sealing ASAP and using good handling techniques and basic sanitation, it’s highly unlikely that anything bad is lurking inside that bag.
Not that you should play with the idea of trying to see how far you can exceed the safe food handling guidelines for time and temperature, but consider how sous vide works to begin with. Milk is pasteurized commercially at 145F for 30 minutes – “low temp long time”. We are told the food danger zone is between 45-140F, but we routinely hold steaks and roasts, pork shoulders, and whole briskets at temps below 140F for hours at a time – like 24 or more for a pork shoulder or even 48 or more for a brisket, and no one dies.
And if your meat is also frozen to begin with, that will help, too. I routinely buy whole primals and cut my own roasts or steaks from the single muscle, season them, vacuum pack them, and put them in the freezer for cooking when I choose. I have not found a significant difference between cooking a steak or roast which was frozen and thawed or one that was cooked directly from fresh (which may actually have been previously frozen before I bought the bag).
As a Jewish kid growing up in the 1950s-60s, we routinely ate chicken, beef, and lamb that was taken from the freezer and left on the counter top to thaw before it was cooked a couple of hours later. Some of us still do that to this day, dodging the danger zone bullets. Now I attend church where we frequently have “potluck” luncheons and dinners where we are blessed not to be sickened by food that left home at least 1-2 hours ago or longer without being insulated against heat loss, has been sitting idly at room temp descending to 120F or much lower while the pastor preaches away.
Although I have not yet tried it, setting up your sous vide pan as an ice water bath at 6am with the intent to begin cooking at 2 or 3 pm for a nice dinner around 5 or 6 pm should not be a problem on any kitchen counter in America where folks are routinely cooking sous vide under “normal” conditions. You could play with the idea in advance to know how long it takes for different ratios of ice to water to reach room temperature or cooking temperature – 60/40 50/50 40/60. You also need to know how long your cooker takes to heat a certain volume of water to your desired temperature . . . my Anova 3.2 takes about 90 minutes to raise 4-5 gallons of 120F hot water from the tap to 185F. I’m sure it would take at least 2 hours to raise 60F water to 130F to cook my steaks, so I would have to know how long it takes for a 35F water bath to reach 60-70F in my kitchen, then how long to get to 130F from there, and backtime all of it to know what time to turn on the Anova for a 6pm sear . . . assuming I don’t get stuck in traffic coming home from work (but, then again, with sous vide, that doesn’t matter at all)…
On the other hand, things that come into our kitchens from the outdoors, like fruits and vegetables, where airborne spores of botulinum abound, but rarely cause problems, you would certainly want to reconsider how you plan to cook them. Allowing them to sit at those unsafe temps too long could be really problematic. And the kinds of bacteria that make us ill or worse, such as E.coli, salmonella, and listeria, which contaminate chicken, cheese/dairy products, and ground beef, well, they are usually introduced through the handling processes in the slaughterhhouses or processing plants that long precede our kitchens, too. So knowing the source of what we consume is important. I would never consider trying to cook those foods “remotely” as this thread originated.
Finally, without a robot or a kid who comes home from school, I can think of no way you would be able to heat then chill a tank of sous vide water and food appropriately in a refrigerated environment.