I work in a hospital, drawing patients, playing with their poop and chunks of their diseased bodies, etc. I almost never get sick, either. But before PB I often did catch the seasonal sniffles that would sweep through the population. Not anymore, I mean just barely, like ONE day of green boogers and then nothing else.
This also. Make a point of not washing my cutting boards, just rinsing dishes with water, and reusing silverware that's been sitting around for a day or two. That, and fermented food in general.
For anyway I'm pretty sure my lack of hygiene has helped. I tend to use the same glass for days, I eat undercooked meat and I've travelled a lot so I'm pretty sure that has given me a strong immune system.
Steak, eggs, potatoes - fruits, nuts, berries and forage. Coconut milk and potent herbs and spices. Tea instead of coffee now and teeny amounts of kelp daily. Let's see how this does! Not really had dairy much, and gut seems better for it.