In vitro digestibility and immunoreactivity of bovine milk proteins

•Current digestibility models solely utilize pepsin stability for safety assessment.•We identified allergenic pepsin and pancreatin stable milk proteins.•β-Lactoglobulin and casein were stable and allergenic within intestinal conditions.•Improved digestibility models are needed for improved food safety assessment. Current models of digestibility solely utilize pepsin stability to assess the safety of allergenic food proteins. However, in vivo complete protein digestion requires acid denaturation and pepsin, trypsin, and/or chymotrypsin cleavage. This study aimed to identify the immunoreactivity and allergenicity of stable bovine milk proteins, using an improved digestibility model to simulate physiological gastric and intestinal conditions in vitro. Gel electrophoresis and immunoblot analysis were used to determine protein stability and immunoreactivity, respectively. Immunoreactivity of bovine milk proteins, β-lactoglobulin (β-LG) and casein (CN) was greatly diminished with gastric simulation (0–60min), but some proteins were stable and immunoreactive with simulated intestinal digestive conditions (0–60min). This study demonstrates the need for improved digestibility models for more accurate assessment of the behavior of food allergens in vivo.