"but many naturally purple-coloured foods contain a certain antioxidant called anthocyanin. These are beneficial plant pigments which give fruit and veg their deep red, purple or blue hues."

Looks to be purple food.

So assuming this is true and not just trying to scare people into podcast views, the likely case is that this theoretical new weapon would use the same/similar backbone as the original WIV strain of commie lung rot, probably with a new spike protein that's New and Improved thanks to what would amount to beta testing, the appropriate common nutrients that would help prevent infection would be the same as/similar to the currently circulating modified virus:

Vitamin D/D3 - Sunlight. Literally just sunlight. Available in supplement form but it's still not as good as sunlight.

Vitamin C - Oranges, broccoli, bell/chili peppers, strawberries, tomatoes, etc etc etc.

Quercetin - Capers, red/yellow onions, shallots, red apples, grapes, cherries, scallions, tomatoes, broccoli, brussel sprouts, cabbage, bell peppers, citrus fruits, asparagus, etc.

Zinc - Red meat (grass-fed is better), chicken, cashews/almonds, spinach, mushrooms, etc.

There are plenty of sources of tablet/pill form of all the above, but again, with these sorts of general nutrients, getting it from food will always be more effective than taking a pill in terms of metabolizing what you're ingesting.

The combination of zinc and quercetin does act as an ACE2 inhibitor which is the same mechanism of action as The Forbidden Horse Paste, but if you do start having cold/flu-like symptoms, just get some ivermectin. And if for whatever reason you can't get ivermectin, it can be substituted with black cumin seeds/oil (nigella sativa), though from what I've read is slightly less effective.

Vitamin C along with the regular immune boosters we've gotten used to from the flu.