I wish I could claim the research was mine (not really), but it belongs to Vaille Swenson. She is currently a Virology and Gene Therapy PhD student at the Mayo Clinic.
In 2019, she wrote her Masters Thesis titled "Assessment and verification of commercially available pressure cookers for laboratory sterilization"
She looked at pressure cookers by Cosori, Gourmia, GoWISE, and Instant Pot.
The following table summarized the time needs to sterilize agar and soil water.
The Instant Pot passed the spore sterilization test, even against known heat resistant Geobacillus stearothermophilus spores.
A sterilization time of at least 150 mins was required for the Instant Pot to inactivate the spores(Figure 2), which appeared similar in color and opacity to a spore ampoule sterilized in anautoclave and the negative control. None of the other pressure cookers inactivated the sporeseven with sterilization times of up to 300 minutes, which yielded unsterilized spore ampoulesvisually identical to a positive control. These data indicated that the Instant Pot pressure cookercould sterilize spores to the level of an autoclave, and we infer that it would be capable ofinactivating all other less heat resistant organisms to properly sterilize laboratory items forresearch.
It took 150 minutes to eliminate that spore. So I would imagine bags of spawn would require at least 150 minutes, if not longer.
The complete thesis can be found --> here for interested parties.