There is not a magical cut-off at 40*. Food will still go bad in the refrigerator at 38* or 34*, it just takes longer. At 44* it will just go bad more quickly. There are charts estimating the times, but these really are just estimates. The salt certainly will help preserve, depending on how much you have. There are so many variables involved, you cannot consider any hard and fast rules. I've had meat go bad in a very cold refrigerator way before the expiration date and I've had it last longer also. You can really tell when meat goes bad just by smelling it. The best way to tell is to use your wife's nose, as her's is more sensitive than yours. That said, when in doubt, I do throw it out, as I just can't enjoy a meal thinking I might be paying for it later.
Incidentally, before the era of refrigeration, not really that long ago, meat often went bad. The remedy was to cook it sufficiently long to destroy anything in it that might kill you, usually turning it into sausage. This really is the key to why spices were such a big deal and so costly in the middle ages. It was to cover up the sour flavor of all the meat that went bad, thus saving a LOT of money. For many of us, eating meat seasoned just with salt is great, but if that meat went bad, the sour would still come through.
Usually, we cook poultry for a pretty long time to kill the bad bacteria -- it's what we were trained to do, the result of the very poor quality meat processing done in the US. The last I read, you have about a 1 in 10,000 chance of getting salmonella poisoning from a chicken egg, suggesting that 1 in 10,000 chickens is contaminated. However, I'm told the processing of chickens is done in large quantities where all the chickens become contaminated. It is estimated that 1 in 3 chickens purchased are contaminated with salmonella, suggesting about 3000 to 4000 chickens are processed at a time before sufficient cleaning is performed. The net result is that we don't have serious problem eating raw or undercooked eggs (small odds of getting sick), but we wouldn't eat raw chicken (high odds of getting sick). Incidentally, in some countries where they process things the old-fashioned way (which is considered unsanitary in the USA), they have no problem eating their chicken cooked medium rare as it is as safe as eating a raw egg.
Assistant to a Mad BBQ Scientist (and a squirrel): Primo Oval XL, Small Offset, Gasser, Optigrill, UBS
"I love everything about the pig, even the way she walks." -- Spanish proverb
(='.'=) This is the rabbit baby. Invests him in yours signature,
(")_(") and the help rabbit baby takes over control of the world!
Hmmmm, I wonder, WWGALD? Avatar courtesy of Grillman and NorthwestBBQ
Promoted by Bigabyte to "Idiot #1"