How "not' to kill mold spores, and the right way

[ithacaartist]

Originally Posted by lugerholsterrepair

My heat treatment has NEVER failed me. It has always worked with no damage providing the leather is left exposed, NOT enclosed.

Jerry, I must concede most of my suggestions are probably more appropriate for something other than holsters, except for the outside of a black one! Although the actual ignition of something in the oven would not quite happen at 350, stuff left in for extended periods winds up black/brown. Everything that gasses off up to 350 will be gone.

I think the success of your method is the two key factors of your instructions: Five minutes, and exposed. I found the chart below, along with some more general discussion of mold. 350 falls somewhere between incineration and an autoclave, but all the times listed are much longer for lesser temps. Your method appears to give a deadly dose of heat to kill the spores, but not so long as to cook off the leather's volatile components--just long enough to "heat it through".

Table 1. Recommended use of heat to control bacterial growth (degrees Celsius)

Incineration >500o Vaporizes organic material on nonflammable surfaces but may destroy many substances in the process

Boiling 100o 30 minutes of boiling kills microbial pathogens and vegetative forms of bacteria but may not kill bacterial endospores

Intermittent boiling 100o Three 30-minute intervals of boiling, followed by periods of cooling kills bacterial endospores

Autoclave and pressure cooker (steam under pressure) 121o/15 minutes at 15# pressure kills all forms of life including bacterial endospores. The substance being sterilized must be maintained at the effective T for the full time

Dry heat (hot air oven) 160o/2 hours For materials that must remain dry and which are not destroyed at T between 121o and 170o Good for glassware, metal, not plastic or rubber items

Dry heat (hot air oven) 170o/1 hour Same as above. Note increasing T by 10 degrees shortens the sterilizing time by 50 percent

Pasteurization (batch method) 63o/30 minutes kills most vegetative bacterial cells including pathogens such as streptococci, staphylococci and Mycobacterium tuberculosis

Pasteurization (flash method) 72o/15 seconds Effect on bacterial cells similar to batch method; for milk, this method is more conducive to industry and has fewer undesirable effects on quality or taste