I know label advice on most products does not allow this for obvious reasons but are there any products that can be sprayed directly onto food preparation surfaces? (wishful thinking or stupid question? you decide)
Are we still talking Biscuit Beetle Tomo or your new diet and enema ? I don't see a non-toxic solution to this particular infestation so it will get the big guns and a quick knock down so that this lady can reclaim her kitchen from the invaders. It will be nice for her to enjoy her breakfast cereal again without crunching beetles.