You can get botulism from store bought processed foods LOL
I use pressure cookers/canners that range in size with weighted gauges and follow the USDA guidlines religiously for cooking times. The time you process at the correct temperature decides what is killed and what isnt, not the cool down period. If you wnt to see a mistake, try opening a pressure cooker or canner immediatley after the timer goes off. You will notice no cool down times on the USDA proceedures as they all state to allow the canner to cool down on its own, thats for your immediate safety not the prevention of botulism. The biggest mistake I see people make is trying to use a hot water bath to can low acid foods.
To each their own ofcourse, but follow those weights and processing times and you will be just fine