student presentation V. T. Nuclear and Radiochemistry Thailand

1. Effects of Low-Dose, Low-Penetration Electron Beam Irradiation of Chilled Beef Carcass Surface Cuts on Escherichia coli O157:H7 and Meat Quality Terrance M. Arthur, Tommy L. Wheeler, Steven D. Shackelford, Joseph M. Bosilevac, Xiangwu Nou, and Mohammad Koohmaraie Presented by Vipavee Trivittayasil

6. Which part of the meat do you think is most likely to be contaminated with E. coli? INSIDE? OUTSIDE?

9. Materials and Methods

15. Pathogen reduction: Meat Sample Warm 40 cutaneous trunci pieces to room temp Outline two 200 cm 2 (10x20 cm) areas using edible ink One section is not treated (control) Another section is treated. Mark 3 areas (5x5 cm) 2 areas (5x5 cm)

16. Marking a piece of cutaneous trunci 3 control (5x5 cm) 2 control (5x5 cm)

25. Results and Discussion

26. Table1 Effect of electron beam irradiation and time post-treatment on E. coli O157:H7 in beef Minimum level of detection = 10 CFU/cm 2 (for direct plating method)

27. Table1 Effect of electron beam irradiation and time post-treatment on E. coli O157:H7 in beef 1.3 log reduction in cell counts for the control sample from 0 to 120 h

28. Table1 Effect of electron beam irradiation and time post-treatment on E. coli O157:H7 in beef The treated ones have cell counts less than 10 CFU/cm 2

29. Table1 Effect of electron beam irradiation and time post-treatment on E. coli O157:H7 in beef 2.9 Log and 2.6 log decrease respectively for 48 h and 120 h

30. Table1 Effect of electron beam irradiation and time post-treatment on E. coli O157:H7 in beef For the high concentration, similar 1.3 log reduction is shown

33. Table 3 Effect of depth of electron beam penetration on trained sensory panel ratings of flank steak Rank from 8 to 1 At 8: Extremely intense None Extremely tender Extremely juicy Extremely intense None

34. Table 3 Effect of depth of electron beam penetration on trained sensory panel ratings of flank steak Rank from 8 to 1 At 8: Extremely intense None Extremely tender Extremely juicy Extremely intense None

36. Table 5 Effect of proportion of irradiated trim and frozen storage time on trained sensory panel ratings of ground beef patties

37. Table 5 Effect of proportion of irradiated trim and frozen storage time on trained sensory panel ratings of ground beef patties All ground beef patty sensory attributes were affected.

38. Table 5 Effect of proportion of irradiated trim and frozen storage time on trained sensory panel ratings of ground beef patties There is no meaningful difference on different treatment group. 100% treatment ranks lowest in every sensory attributes

39. Table 5 Effect of proportion of irradiated trim and frozen storage time on trained sensory panel ratings of ground beef patties The significant effect of frozen storage time are not logical and may not be of importance

40. Table 6 Effect of proportion of irradiated trim on color of raw ground beef patties No significant effect on color

41. Conclusion

44. THANK YOU FOR YOUR ATTENTION