It's pretty well-known and scientifically established that rather cool temperatures are bad for bread: putting your bread in the refrigerator will tend to dry it out and accelerate chemical reactions in the starches that cause staling (as discussed, for example, in some answers to this question). Freezing, on the other hand, stops some of those reactions and is a common method for maintaining bread quality for longer storage. Regardless of quality issues, both types of cooling will help to prevent molding, so there are trade-offs.
My question is: what happens when we store bread at warmer temperatures, say in the 90-130F range (about 35-55C)? How will quality be affected? Will the shelf-life be altered? Are the effects only good, only bad, or mixed? I'm particularly interested in short-term holding (less than a day) at elevated temperatures.
Also, are there any food safety issues raised by a practice like this (i.e., worse than bread storage at room temperature)? Bread is not a particularly good growth medium for bacteria, but I imagine that Bacillus cereus or something might be at least a potential concern.
[Background, for those who are curious: The reason I ask this question is because I sometimes need to store bread temporarily in a hot car. The only bakery near me that I trust to make decent bread sometimes has "day-old" bread on sale for half price. Their normal prices are, to my mind, excessively high; so if I can't buy their loaves for half-price, I usually just make bread myself. Occasionally, I'll pick up some loaves on the way to work, but it's inconvenient to take them back home immediately. And while I have sometimes carried them into work with me, it would be easier to just leave them in my car. I also can't pick up the bread on the way home, because the half-price bread (when they have it) generally sells out by mid-morning. Although I can sometimes park under a tree or something, the reality is that the summer sun will often raise the temperature of my car interior to above 100F. Thus, the bread will be subjected to quite a few hours of elevated temperatures. I've done this once or twice without a major change in quality, but I'm wondering if there are benefits to justify the inconvenience of keeping it near room temperature.]