Elisa,

I've searched through my "stuff" and came up with a couple of references to
studies that might be helpful.  They aren't specifically about iron content
in abm but are related to iron supplementation.

J.J. Bullen et al., "Iron-Binding Proteins in Milk and Resistance to
Escherichia coli Infection in Infants," British Medical Journal, 69:69-77,
January, 1972.
(The protein lactoferrin, when saturated with iron, loses it's ability to
inhibit the growth of bacteria.)

R.R. Arnold et al., "A Bacteriocidal Effect for Human Lactoferrin," Science,
197:263-264, 1977.
(In the absence of iron supplements, lactoferrin can destroy bacteria
responsible for tooth decay.)

Hope these help.

Diane Karnbach, LLLL
Virginia Beach, VA