This article positions as something invented between the USA and the USSR... But, just looking into wikiepdia:
"One such solution was a method proposed in 1809 by the French pastry chef Nicolas François Appert, which involved long-cooking meat or vegetables (approximately 1-2 hours) and pasteurizing the finished product in a brine solution. Appert received a personal award for this invention from Napoleon."
Thanks for posting this. I knew what Tushonka is from the game Escape from Tarkov, but like other Russian food items in that game, it's presented in a limited, practical context, so it was cool to learn more about it.