Date of Award:

5-2011

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Nutrition, Dietetics, and Food Sciences

Committee Chair(s)

Conly Hansen

Committee

Conly Hansen

Committee

Daren Cornforth

Committee

Silvana Martini

Committee

Wynn Walker

Committee

Charles Carpenter

Committee

Frost Steele

Abstract

High-pressure needleless injection (HPNI) is a process where small-diameter, high-velocity burst of liquid, penetrate foods at pressures ≤ 10,000 psi. The potential of HPNI as an enhancing technique for meat was studied. In study 1, HPNI translocated surface E. coli O157 into the interior of beef eye-of-round subprimals with an incidence of 40 (±7), 25 (±8), and 25 (±8)% for meat that had been surface-inoculated with a four-strain cocktail at 0.5, 1, and 2 log10 CFU/cm2, respectively. Run-off water contained 2, 2, and 3 log10 CFU/ml and was used for HPNI of additional subprimals, which resulted in a cross-contamination incidence of 83 (±4), 60 (±15), and 37 (±6) %, respectively. Incidence of translocation and cross-contamination was similar at all sampled levels below the inoculated surface. Study 1 results indicate that surface microflora will be translocated from the surface into the interior of HPNI-treated beef by the injection fluid and by cross-contamination with recycled fluid.

In study 2, E. coli was undetected in cooked steaks (63˚C internal) cut from subprimals inoculated with 2 log10 CFU/cm2 and HPNI processed (study 1). Although cooking reduced E. coli counts, determination of complete kill was not possible because the detection limit for bacterial recovery was about 1 log10 CFU/g. Steaks cut from HPNI-processed subprimals took longer (p < 0.05) to reach 63˚C with grilling or broiling, compared to control steaks, possibly due to increased moisture in enhanced steaks.

In study 3, sensory acceptance of steaks was evaluated by a consumer panel. Appearance, flavor, and overall acceptance were similar among the untreated control, HPNI steaks, blade tenderized steaks (BT steaks), and steaks cut from subprimals that had been needle-injected with 0.35% (wt/vol) sodium tripolyphosphate using needle injection (NI-subprimal steaks) or HPNI (HPNI-subprimal steaks). Texture of BT steaks (6.5±1.9) was more liked than control steaks (5.8±1.8), while texture was similar for all other comparisons. Conversely, Warner-Bratzler shear force was NI-subprimal steaks < control < HPNI steaks = HPNI-subprimal steaks = BT steaks. Lack of correspondence between texture acceptance data and WBSF suggests that sensory scores were influenced by factors other than the force required for mechanical shear.

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Comments

This work was made publicly available electronically on September 30, 2011.

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