Purification and characterization of tinamou egg white ovotransferrin as an antimicrobial agent against foodborne pathogenic bacteria

- Purified tinamou OTF was identified by peptide mass fingerprinting.
- Chicken and tinamou OTFs were antimicrobial against E. coli O157:H7 and S. aureus.
- Antimicrobial activity was concentration, NaHCO3 and iron saturation dependent.
- Tinamou OTF has potential as a natural antimicrobial agent for food industry use.

Chilean tinamou (Nothoprocta perdicaria) egg white ovotransferrin was purified with anion-exchange Fast Protein Liquid Chromatography and identified by peptide mass fingerprinting. Tinamou egg white ovotransferrin was compared to chicken (Gallus gallus) and emu (Dromaius novaehollandiae) ovotransferrin by SDS-PAGE analysis. Though all three species contained similar molecular weight ovotransferrins, tinamou egg white contained 20% more ovotransferrin than chicken, but 30% less than emu.The effectiveness of tinamou ovotransferrin as a natural antimicrobial agent was compared to chicken ovotransferrin against two food related pathogens, Escherichia coli O157:H7 and Staphylococcus aureus. The bacteriostatic and bactericidal activities of the native, apo and holo forms of the proteins were dependent on the presence of 50 mM bicarbonate and protein iron saturation. Native ovotransferrins were the most effective at a concentration of 10 mg/ml with 50 mM bicarbonate, exhibiting bacteriostatic and bactericidal activities against both pathogens. Holo ovotransferrins exhibited moderate antimicrobial activity in the presence of bicarbonate. Different antimicrobial activities were observed between chicken and tinamou ovotransferrins, suggesting tinamou ovotransferrin may possess unique antimicrobial motifs that warrant further investigation of its amino acids composition. Further, our results suggest that tinamou ovotransferrin may represent a natural antimicrobial agent suitable for use in food matrices or on food preparation surfaces.