At least some of the wax that is melted down for foundation must come from AFB infected colonies, and it is known that cappings wax taken directly from AFB colonies can contain large numbers of spores (up to 9 million/gm). However, most of the AFB spores are removed by the initial melting and later processing of wax into foundation.
Tests have been carried out on eight lines of foundation produced in New Zealand and no AFB spores were found. Foundation is probably therefore no more than a very minor source of cross-infection.
Foundation is not thought to be an important factor in the spread of AFB.