1. Effect of cold pasteurization on the color and flavor of frozen packaged ground beef patties D. D. Johnson University of Florida

2. Objectives Does increasing dosage level of irradiation affect visual and sensory properties of ground beef patties? Does increasing dosage level of irradiation affect visual and sensory properties of ground beef patties? Does chill state at cooking affect visual and sensory properties? Does chill state at cooking affect visual and sensory properties?

3. Process Formulation Formulation 15% fat 15% fat.1% Rosemary Extract.1% Rosemary Extract 1/4 Lb. Patties 1/4 Lb. Patties Frozen (-40°C) Frozen (-40°C) Packaged (D955 Thermoform laminate Cryovac Seal Air Corp.) Packaged (D955 Thermoform laminate Cryovac Seal Air Corp.) Irradiated with electron beam 0,.5, 1, 2, 3 or 4 kGy (Florida Accelerator Services and Technology) Irradiated with electron beam 0,.5, 1, 2, 3 or 4 kGy (Florida Accelerator Services and Technology)

4. Process Kept Frozen at -40°C Kept Frozen at -40°C Thawed Thawed  Color  Grilled to 71°C Frozen Frozen  Color  Grilled to 71°C

5. Effect of Irradiation Level and Chill State on Color and Discoloration of Ground Beef Patties 4.5 a 4.7 a Thawed 4.5 a 4.8 a Frozen Chilled State 2.1 e 2.7 e 4.0 2.5 d 3.2 d 3.0 3.5 c 4.1 c 2.0 5.9 b 5.8 b 1.0 6.0 b 5.8 b 0.5 7.0 a 6.9 a 0DiscolorationColor Irradiation, kGy Color scale: 8 = light cherry red; 1 = extremely dark red or brown Discoloration: 8 = no discoloration; 1 = 100% discolored. a-e Means in a column lacking a common superscript differ (P <.05)

9. Measuring Color: CIE Color Space

10. Effect of Irradiation Level and Chill State on Hunter Color Measurements in Ground Beef Patties Hunter Values 11.9 b 19.4 b 46.5Thawed 12.2 a 18.4 a 47.7Frozen Chilled State 10.6 f 15.3 f 46.24.0 11.2 e 16.1 e 47.33.0 11.6 d 17.6 d 46.32.0 12.4 c 19.8 c 48.21.0 12.7 b 20.9 b 46.80.5 13.6 a 23.8 a 47.80 b* b* a* a* L* L* Irradiation, kGy a-f Means in a column lacking a common superscript differ (P <.05)

11. Effect of Irradiation Level and Chill State on Sensory Properties of Ground Beef Patties 5.0 a 5.2 b Thawed 5.1 a 5.0 a Frozen Chill State 5.0 ab 5.04.0 5.1 b 5.13.0 5.3 b 5.22.0 5.4 b 5.41.0 5.3 b 5.00.5 4.7 a 5.10Off-flavorOff-odor Irradiation, kGy Off-odor scores: 5 = Threshold, barely detected; 4 = slight Off-flavor scores: 5 = Threshold, barely detected; 4 = slight a,b Means in a column lacking a common superscript differ (P <.05)

12. Summary 1. As irradiation level increased, color became darker and more reddish brown. 2. As irradiation level increased, discoloration increased. 3. Off-odors were not affected by irradiation level, but patties thawed before cooking had slightly less off-odor. 4. Irradiated patties had less off-flavor than non- irradiated patties.

13. Conclusion End users may perceive quality changes (color, discoloration) in ground beef patties irradiated at high levels. However, we did not detect sensory changes at the levels evaluated. End users may perceive quality changes (color, discoloration) in ground beef patties irradiated at high levels. However, we did not detect sensory changes at the levels evaluated.