If you are an actual gaffer, you'd better learn up on it asap. The guts are the primary arena of your immune system and when they fall apart, everything falls apart.
Sheesh....I’m 73 and know about good and bad intestinal microbes and immunity. The “FLORA” moniker threw me because it’s stupid.
BTW, a gaffer can be one of several things. In England it can mean a boss, other places it can mean an old fart, in TV and film it means chief electrician, etc. Some places it can also mean an electrician
I have been or am most of those.