Effects of Low-Dose, Low-Penetration Electron Beam Irradiation of Chilled Beef Carcass Surface Cuts on Escherichia coli O1...
Escherichia coli O157:H7 <ul><li>E. Coli O157:H7 produced toxins that   cause severe illness </li></ul><ul><li>Can be foun...
Escherichia coli O157:H7 <ul><li>E. coli is a target pathogen for control in the beef processing technology. </li></ul>
Incidents of E. coli <ul><li>2008, Jan:  A Minnesota meatpacker has recalled about 188,000 pounds of ground beef patties b...
Irradiation <ul><li>Many studies show irradiation significantly reduced foodborne pathogen concentration. </li></ul><ul><l...
Which part of the meat do you think is most likely to be contaminated with E. coli? INSIDE? OUTSIDE?
Low-dose low-penetration E-beam <ul><li>Electron beam technology has been developed such that large nonuniform surface are...
Objectives <ul><li>To assess the efficacy of E-beam irradiation for reducing concentrations of E. coli O157:H7 on carcass ...
Materials and Methods
Outline of Methods <ul><li>Pathogen Reduction Ability of Irradiation </li></ul><ul><ul><li>Detecting/enumerating E. coli <...
Samples <ul><li>Chilled beef carcasses </li></ul><ul><ul><li>Cutaneous Trunci </li></ul></ul>
Samples <ul><li>Chilled beef carcasses </li></ul><ul><ul><li>Cutaneous Trunci </li></ul></ul><ul><ul><li>Flank Steak </li>...
Samples <ul><li>Chilled beef carcasses </li></ul><ul><ul><li>Cutaneous Trunci </li></ul></ul><ul><ul><li>Flank Steak </li>...
E-beam Irradiation <ul><li>3-MeV Dynamitron at a dosage of 1 kGy/s </li></ul><ul><li>Dynamitron is an accelerator allowing...
Pathogen reduction: Meat Sample Warm 40 cutaneous trunci pieces to room temp Outline two 200 cm 2  (10x20 cm) areas using ...
Marking a piece of cutaneous trunci  3 control (5x5 cm) 2 control (5x5 cm)
Pathogen reduction: strain <ul><li>E. coli O157:H7 strain lacking both Shiga toxins was used for inoculation </li></ul><ul...
Pathogen reduction: inoculation <ul><li>To inoculate, 4 ml of appropriate culture dilution was dispensed across the 400 cm...
After inoculation <ul><li>For each cutaneous trunci, </li></ul><ul><ul><li>Control1    remain at room T for 1 h </li></ul...
Pathogen reduction: detection and enumeration of E. coli <ul><li>Detecting E. coli </li></ul><ul><ul><li>Direct Plating </...
<ul><li>30 flank steaks with 20 mm thickness </li></ul><ul><li>They were randomly assigned to irradiation: </li></ul><ul><...
Meat quality evaluation: flank steaks <ul><li>After radiation treatment, steaks were stored at 5C for 12-14 days. </li></u...
Meat quality evaluation: ground beef patties <ul><li>Boneless chuck short ribs were sliced into 2 cm think strips and tran...
Meat quality evaluation: ground beef patties <ul><li>Proportions prepared: </li></ul><ul><ul><li>(1) 100% treated </li></u...
Results and Discussion
Table1 Effect of electron beam irradiation and time post-treatment on E. coli O157:H7 in beef Minimum level of detection =...
Table1 Effect of electron beam irradiation and time post-treatment on E. coli O157:H7 in beef 1.3 log reduction in cell co...
Table1 Effect of electron beam irradiation and time post-treatment on E. coli O157:H7 in beef The treated ones have cell c...
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...
Table1 Effect of electron beam irradiation and time post-treatment on E. coli O157:H7 in beef For the high concentration, ...
Table 2 MPN estimates for E. coli O157:H7 following electron beam irradiation of beef <ul><li>MPN Method </li></ul><ul><ul...
Table 2 MPN estimates for E. coli O157:H7 following electron beam irradiation of beef <ul><ul><li>The results are similar ...
Table 3 Effect of depth of electron beam penetration on trained sensory panel ratings of flank steak Rank from 8 to 1 At 8...
Table 3 Effect of depth of electron beam penetration on trained sensory panel ratings of flank steak Rank from 8 to 1 At 8...
Table 4 Effect of depth of electron beam penetration on color of raw flank steak <ul><li>Shows a dose-related pattern </li...
Table 5 Effect of proportion of irradiated trim and frozen storage time on trained sensory panel ratings of ground beef pa...
Table 5 Effect of proportion of irradiated trim and frozen storage time on trained sensory panel ratings of ground beef pa...
Table 5 Effect of proportion of irradiated trim and frozen storage time on trained sensory panel ratings of ground beef pa...
Table 5 Effect of proportion of irradiated trim and frozen storage time on trained sensory panel ratings of ground beef pa...
Table 6 Effect of proportion of irradiated trim on color of raw ground beef patties No significant effect on color
Conclusion
Conclusion <ul><li>Low-dose, low-penetration E-beam irradiation has great potential as an antimicrobial intervention in th...
Controversy <ul><li>Cartoon by John Jonik </li></ul>
THANK YOU FOR YOUR ATTENTION
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Effects of low-dose e-beam (student preso)

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Nuclear and Radiochemistry
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  • Flank steak is used as a model muscle because it is partially surface exposed, consistent in size, shape and location, and easy to access and remove and possesses sufficient surface fat to allow appropriate trimming and surface layer molding to achieve variable penetration
  • Effects of low-dose e-beam (student preso)

    1. 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
    2. 2. Escherichia coli O157:H7 <ul><li>E. Coli O157:H7 produced toxins that cause severe illness </li></ul><ul><li>Can be found in human and animal’s intestines </li></ul><ul><li>Its presence indicates fecal contamination </li></ul>
    3. 3. Escherichia coli O157:H7 <ul><li>E. coli is a target pathogen for control in the beef processing technology. </li></ul>
    4. 4. Incidents of E. coli <ul><li>2008, Jan: A Minnesota meatpacker has recalled about 188,000 pounds of ground beef patties because of E . coli bacteria concerns after five illnesses were reported. </li></ul><ul><li>2007, Oct : Recall of 21.7 million pounds of Topp’s frozen beef after reports of 37 patients with diarrhea, 21 were hospitalized. </li></ul>Source: Msnbc
    5. 5. Irradiation <ul><li>Many studies show irradiation significantly reduced foodborne pathogen concentration. </li></ul><ul><li>Traditionally, high-penetration and high-energy radiation is needed to ensure uniform treatment of both exposed surface and internal regions. </li></ul><ul><li>However this leads to off-odors and may affect flavor. </li></ul>
    6. 6. Which part of the meat do you think is most likely to be contaminated with E. coli? INSIDE? OUTSIDE?
    7. 7. Low-dose low-penetration E-beam <ul><li>Electron beam technology has been developed such that large nonuniform surface areas can be effectively treated. </li></ul><ul><li>Only the surface of beef (15 mm penetration) can be treated with E-beam. </li></ul><ul><li>Since pathogen contamination is a surface phenomenon, this treatment is expected to significantly reduces the pathogen load. </li></ul>
    8. 8. Objectives <ul><li>To assess the efficacy of E-beam irradiation for reducing concentrations of E. coli O157:H7 on carcass surface tissues. </li></ul><ul><li>To evaluate the effect of E-beam irradiation on product quality. </li></ul>
    9. 9. Materials and Methods
    10. 10. Outline of Methods <ul><li>Pathogen Reduction Ability of Irradiation </li></ul><ul><ul><li>Detecting/enumerating E. coli </li></ul></ul><ul><li>Meat Quality Evalutaion: Flank Steaks </li></ul><ul><ul><li>Sensory Attributes </li></ul></ul><ul><ul><li>Color  consumer purchase decision </li></ul></ul><ul><li>Meat Quality Evalutaion: Ground Beef Patties </li></ul><ul><ul><li>Sensory Attributes </li></ul></ul><ul><ul><li>Color </li></ul></ul>
    11. 11. Samples <ul><li>Chilled beef carcasses </li></ul><ul><ul><li>Cutaneous Trunci </li></ul></ul>
    12. 12. Samples <ul><li>Chilled beef carcasses </li></ul><ul><ul><li>Cutaneous Trunci </li></ul></ul><ul><ul><li>Flank Steak </li></ul></ul>
    13. 13. Samples <ul><li>Chilled beef carcasses </li></ul><ul><ul><li>Cutaneous Trunci </li></ul></ul><ul><ul><li>Flank Steak </li></ul></ul><ul><ul><li>Ground Beef Patties </li></ul></ul>
    14. 14. E-beam Irradiation <ul><li>3-MeV Dynamitron at a dosage of 1 kGy/s </li></ul><ul><li>Dynamitron is an accelerator allowing rapid and easy computer control for any voltage from 0.3 MeV to 4.0 MeV. </li></ul>
    15. 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. 16. Marking a piece of cutaneous trunci 3 control (5x5 cm) 2 control (5x5 cm)
    17. 17. Pathogen reduction: strain <ul><li>E. coli O157:H7 strain lacking both Shiga toxins was used for inoculation </li></ul><ul><li>It was grown overnight to ~5x10 8 CFU/ml </li></ul>CFU = Colony Forming Unit
    18. 18. Pathogen reduction: inoculation <ul><li>To inoculate, 4 ml of appropriate culture dilution was dispensed across the 400 cm2 area using a sterile spreader. </li></ul>20 10 3 Low Inoculation 20 10 6 High Inoculation No. of cutaneous trunci to be inoculated CFU/cm 2 Level
    19. 19. After inoculation <ul><li>For each cutaneous trunci, </li></ul><ul><ul><li>Control1  remain at room T for 1 h </li></ul></ul><ul><ul><li>Control2 </li></ul></ul><ul><ul><li>Control3 </li></ul></ul><ul><ul><li>Treated1 </li></ul></ul><ul><ul><li>Treated2 </li></ul></ul><ul><li>For the treated, they were irradiated. </li></ul><ul><li>All samples will be aerobically bagged, refrigerated, and shipped for processing. </li></ul>Refridgerated overnight
    20. 20. Pathogen reduction: detection and enumeration of E. coli <ul><li>Detecting E. coli </li></ul><ul><ul><li>Direct Plating </li></ul></ul><ul><li>Enumeration of E. coli </li></ul><ul><ul><li>MPN </li></ul></ul>
    21. 21. <ul><li>30 flank steaks with 20 mm thickness </li></ul><ul><li>They were randomly assigned to irradiation: </li></ul><ul><ul><li>(1) 75% muscle penetration (no fat tissue) </li></ul></ul><ul><ul><li>(2) 50% muscle penetration (5mm fat tissue) </li></ul></ul><ul><ul><li>(3) 25% muscle penetration (10mm fat tissue) </li></ul></ul><ul><ul><li>(4) 10% muscle penetration (13mm fat tissue) </li></ul></ul><ul><ul><li>(5) 0% muscle penetration (untreated control) </li></ul></ul>Meat quality evaluation: flank steaks
    22. 22. Meat quality evaluation: flank steaks <ul><li>After radiation treatment, steaks were stored at 5C for 12-14 days. </li></ul><ul><li>They were cut into cubes and stir-fried before being sensory tested by 10 trained sensory panel. </li></ul>
    23. 23. Meat quality evaluation: ground beef patties <ul><li>Boneless chuck short ribs were sliced into 2 cm think strips and transported at -3C to irradiation center. </li></ul><ul><li>After radiation treatment, they were prepared into ground beef. </li></ul>
    24. 24. Meat quality evaluation: ground beef patties <ul><li>Proportions prepared: </li></ul><ul><ul><li>(1) 100% treated </li></ul></ul><ul><ul><li>(2) 50% treated + 50% control </li></ul></ul><ul><ul><li>(3) 25% treated + 75% control </li></ul></ul><ul><ul><li>(4) 10% treated + 90% control </li></ul></ul><ul><ul><li>(5) 5% treated + 95% control </li></ul></ul><ul><ul><li>(6) 100% control </li></ul></ul><ul><li>Evaluate for sensory testing after 20 days and 40 days of frozen storage. </li></ul>
    25. 25. Results and Discussion
    26. 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. 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. 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. 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. 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
    31. 31. Table 2 MPN estimates for E. coli O157:H7 following electron beam irradiation of beef <ul><li>MPN Method </li></ul><ul><ul><li>Detection limit = 0.036 CFU/cm2 </li></ul></ul><ul><ul><li>Enrichment >> Selective Plating </li></ul></ul><ul><ul><li>Allow recovery of injured cells </li></ul></ul>
    32. 32. Table 2 MPN estimates for E. coli O157:H7 following electron beam irradiation of beef <ul><ul><li>The results are similar to table 1, but shows more accurate number of cells surviving irradiation. </li></ul></ul><ul><ul><li>Cells after irradiation were very low </li></ul></ul>
    33. 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. 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
    35. 35. Table 4 Effect of depth of electron beam penetration on color of raw flank steak <ul><li>Shows a dose-related pattern </li></ul><ul><li>Any treatment, except 75%, is unlikely to affect consumer purchase decision </li></ul>
    36. 36. Table 5 Effect of proportion of irradiated trim and frozen storage time on trained sensory panel ratings of ground beef patties
    37. 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. 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. 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. 40. Table 6 Effect of proportion of irradiated trim on color of raw ground beef patties No significant effect on color
    41. 41. Conclusion
    42. 42. Conclusion <ul><li>Low-dose, low-penetration E-beam irradiation has great potential as an antimicrobial intervention in the beef slaughter process. </li></ul>
    43. 43. Controversy <ul><li>Cartoon by John Jonik </li></ul>
    44. 44. THANK YOU FOR YOUR ATTENTION

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