Apparently this is an advertising slogan for the Thermapen BBQ temperature gauge.
Note 1 of the Food Standards Agency document shows us that, “cooking food until the CORE TEMPERATURE is 75c or above will ensure that harmful bacteria are destroyed.“ This is the reason why I use the saying “75 – Stay Alive!” to help people remember the final temperature of well done meats. If you read further down the document you will see there are other variations, but for the bulk of what we do at home, cooking food to an internal temperature of 75c will mean you serve up food that is safely cooked, time and time again. It will also save so many people from overcooking food and allowing it to become dry and tough.
Oh well. https://www.richardholdenbbq.co.uk/bbq-masterclass-thermapen/