STUDIES ON THE ALLERGENICITY OF COW'S MILK III. Effect of Heat Treatment on the Allergenicity of Milk and Protein Fractions from Milk as Tested in Guinea Pigs by Sensitization and Challenge by the Oral Route

Oral challenge with heat-denatured milk produced no reactions in guinea pigs sensitized parenterally to beta-lactoglobulin and alpha-lactalbumin, but produced typical anaphylactic reactions in animals sensitized to the heat-stable alpha-casein. In contrast, feeding of pasteurized skimmed milk resulted in frequent reactions in animals sensitized to alpha-casein and betalactoglobulin and one reaction in an animal sensitized to alpha-lactalbumin. Oral administration of heat-denatured milk failed to produce sensitization, even as tested by intravenous challenge with pasteurized skimmed milk. In contrast, pasteurized skimmed milk, given orally, resulted in sensitization of about two-thirds of the animals, as tested later by oral challenge with pasteurized skimmed milk, and of an even greater proportion as tested by intravenous challenge. Although alpha-casein is generally considered to be heat stable, under the conditions of these experiments the evidence indicated that it may be partially denatured by heat. These studies, designed to stimulate clinical sensitization to milk, suggest that heatdenatured milk can be fed safely to individuals allergic to milk, unless they are extraordinarily sensitive to the heat-stable alpha-casein.