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The objective of the current study was to evaluate the effects of aging on myoglobin chemistry of dark-cutting beef. Ten USDA Choice (mean pH = 5.6; normal pH beef) and 10 no-roll dark cutter (mean pH = 6.4) strip loins were obtained from a commercial packing plant within 3 d of harvest. Loins were cut into 4 sections, vacuum packaged, randomly assigned to 0-, 21-, 42-, and 62-d aging at 2°C in the dark. Following aging, loin sections were cut into 2.5-cm-thick steaks and were used to determine bloom development, oxygen consumption (OC), metmyoglobin reducing activity (MRA), and lipid oxidation. Surface color readings were measured using a HunterLab Miniscan XE Plus spectrophotometer. A significant muscle type × aging time interaction resulted for OC ( < 0.001). Normal pH steaks declined more ( < 0.001) in OC during aging than dark-cutting beef. On d 0, dark-cutting beef had a greater OC ( < 0.001) than normal pH beef. There was a significant muscle type × oxygenation time × aging period interaction for L* values, deoxymyoglobin (DeoxyMb), and oxymyoglobin (OxyMb). When dark-cutting sections were aged for 62 d, both 0 and 60 min bloom development L* values were greater ( < 0.0001) than 0 min dark-cutting sections aged for 21 or 42 d. At all aging periods, normal pH beef had greater OxyMb content and lower DeoxyMb ( < 0.0001) during bloom development than dark-cutting beef. An aging period × muscle type interaction was significant for % overall reflectance ( = 0.0017) and absorbance ( = 0.0038). Dark cutting and normal pH beef loin sections aged for 62 d had greater reflectance ( < 0.0001) than 21 d. On d 0, dark-cutting beef had greater ( < 0.0001) MRA than normal pH beef. There were no significant ( = 0.14) differences in MRA between 42 and 62 d between dark-cutting and normal pH beef. Dark cutting steaks had lower thiobarbituric acid reactive substances values ( < 0.0001) than normal pH steaks. The results indicate that characterizing the myoglobin chemistry during aging will help to design strategies to improve appearance of high pH beef.

The objective was to evaluate the effects of wet-aging, rosemary-enhancement, and modified atmospheric packaging on the color of dark-cutting beef during simulated retail display. No-roll dark-cutting strip loins ( = 12; pH > 6.0) were selected from a commercial packing plant within 3 d postharvest. Using a balanced incomplete block design, dark-cutting loins were sectioned in half, and assigned to 1 of 3 aging periods: 7, 14, or 21 d. After respective aging, each aged section was divided into 3 equal parts, and randomly assigned to 1 of 3 enhancement treatments: nonenhanced dark-cutting, dark-cutter enhanced with 0.1% rosemary, and dark-cutter enhanced with 0.2% rosemary. Following enhancement, steaks were randomly assigned to 1 of 3 packaging treatments: high-oxygen modified atmospheric packaging (HiOx-MAP; 80% O and 20% CO), carbon monoxide modified atmospheric packaging (CO-MAP; 0.4% CO, 69.6% N, and 30% CO), and polyvinyl chloride overwrap (PVC; 20% O). Instrumental and visual color measurements were recorded during 5 d simulated retail display. Lipid oxidation was determined utilizing the thiobarbituric acid reactive substances (TBARS) method. There was a significant packaging × enhancement × display time interaction for values and chroma ( 0.001). On d 0 of display, dark-cutting steaks enhanced with 0.1% and 0.2% rosemary and packaged in HiOx-MAP had greater ( 0.001) values and chroma than other dark-cutting packaging/enhancement treatments. A significant packaging × enhancement × display time interaction resulted for values ( 0.001). Dark-cutting steaks enhanced with 0.2% rosemary and packaged in HiOx-MAP was lighter ( 0.001; greater values) than other dark-cutting treatments on d 5 of display. There were no differences ( 0.34) in discoloration scores on d 5 among different dark-cutting treatments when steaks were packaged in HiOx- and CO-MAP. There was an aging period × enhancement × packaging interaction ( < 0.0033) for lipid oxidation. On d 0 of display, there were no differences ( 0.54) in TBARS values between different aging periods and enhancement treatments. Dark-cutting steaks enhanced with 0.2% rosemary had lower ( 0.001) TBARS values than 0.1% rosemary on d 5 when aged for 21 d and in HiOx-MAP. The results suggest that rosemary enhancement with CO- or HiOx-MAP has the potential to improve the surface color of dark-cutting beef.

ABSTRACT The objective was to evaluate the effects of wet-aging, rosemary-enhancement, and modified atmospheric packaging on the color of dark-cutting beef during simulated retail display. No-roll dark-cutting strip loins (n = 12; pH > 6.0) were selected from a commercial packing plant within 3 d postharvest. Using a balanced incomplete block design, dark-cutting loins were sectioned in half, and assigned to 1 of 3 aging periods: 7, 14, or 21 d. After respective aging, each aged section was divided into 3 equal parts, and randomly assigned to 1 of 3 enhancement treatments: nonenhanced dark-cutting, dark-cutter enhanced with 0.1% rosemary, and dark-cutter enhanced with 0.2% rosemary. Following enhancement, steaks were randomly assigned to 1 of 3 packaging treatments: high-oxygen modified atmospheric packaging (HiOx-MAP; 80% O2 and 20% CO2), carbon monoxide modified atmospheric packaging (CO-MAP; 0.4% CO, 69.6% N, and 30% CO2), and polyvinyl chloride overwrap (PVC; 20% O2). Instrumental and visual color measurements were recorded during 5 d simulated retail display. Lipid oxidation was determined utilizing the thiobarbituric acid reactive substances (TBARS) method. There was a significant packaging × enhancement × display time interaction for a* values and chroma (P < 0.001). On d 0 of display, dark-cutting steaks enhanced with 0.1% and 0.2% rosemary and packaged in HiOx-MAP had greater (P < 0.001) a* values and chroma than other dark-cutting packaging/enhancement treatments. A significant packaging × enhancement × display time interaction resulted for L* values (P < 0.001). Dark-cutting steaks enhanced with 0.2% rosemary and packaged in HiOx-MAP was lighter (P < 0.001; greater L* values) than other dark-cutting treatments on d 5 of display. There were no differences (P = 0.34) in discoloration scores on d 5 among different dark-cutting treatments when steaks were packaged in HiOx- and CO-MAP. There was an aging period × enhancement × packaging interaction (P < 0.0033) for lipid oxidation. On d 0 of display, there were no differences (P = 0.54) in TBARS values between different aging periods and enhancement treatments. Dark-cutting steaks enhanced with 0.2% rosemary had lower (P < 0.001) TBARS values than 0.1% rosemary on d 5 when aged for 21 d and in HiOx-MAP. The results suggest that rosemary enhancement with CO- or HiOx-MAP has the potential to improve the surface color of dark-cutting beef.

Recent reports of biovolatilisation of phosphorus and antimony by anaerobic bacteria and of leaching of phosphorus and antimony fire-retardant additives from PVC cot mattress covers, indicate that the polyurethane inner-foam of cot mattresses could be a site for generation of toxic gases of group 15 elements. A toxic gas hypothesis for sudden infant death syndrome (SIDS) involving polyurethane foam of cot mattresses was proposed and tested experimentally. Levels of antimony, phosphorus, arsenic and bismuth were determined at four sites for 44 SIDS and 50 control (no death) cot mattress foams. There was no evidence to suggest that the levels of these elements in cot mattress foam have a causal relation to SIDS. Leaching of antimony trioxide from PVC mattress covers could account for detectable levels of this element in 52% of the cot mattress samples analysed. Volatile forms of antimony, phosphorus, arsenic and bismuth was not detected in the headspace of mixed or monoseptic cultures of anaerobic bacteria containing polyurethane foam. Past microbial activity had given rise to involatile methylated species of antimony in some of the cot mattress foams tested (61%, n = 24). Abiotic oxidation of biogenic trimethylatimony together with physical adsorption of methylantmony forms to the polyurethane foam matrix could account for the apparent absence of “escaped” volatile antimony species in culture headspaces of incubation vial. There was no evidence to suggest that levels of trimethylantimony or total methylantimony forms in cot mattress foams have a causal relation to SIDS.

The objective was to evaluate the effects of wet-aging, rosemary-enhancement, and modified atmospheric packaging on the color of dark-cutting beef during simulated retail display. No-roll dark-cutting strip loins (n = 12; pH > 6.0) were selected from a commercial packing plant within 3 d postharvest. Using a balanced incomplete block design, dark-cutting loins were sectioned in half, and assigned to 1 of 3 aging periods: 7, 14, or 21 d. After respective aging, each aged section was divided into 3 equal parts, and randomly assigned to 1 of 3 enhancement treatments: nonenhanced dark-cutting, dark-cutter enhanced with 0.1% rosemary, and dark-cutter enhanced with 0.2% rosemary. Following enhancement, steaks were randomly assigned to 1 of 3 packaging treatments: high-oxygen modified atmospheric packaging (HiOx- MAP; 80% O2 and 20% CO2), carbon monoxide modified atmospheric packaging (CO-MAP; 0.4% CO, 69.6% N, and 30% CO2), and polyvinyl chloride overwrap (PVC; 20% O2). Instrumental and visual color measurements were recorded during 5 d simulated retail display. Lipid oxidation was determined utilizing the thiobarbituric acid reactive substances (TBARS) method. There was a significant packaging ... enhancement ... display time interaction for a* values and chroma (P < 0.001). On d 0 of display, dark-cutting steaks enhanced with 0.1% and 0.2% rosemary and packaged in HiOx-MAP had greater (P < 0.001) a* values and chroma than other dark-cutting packaging/ enhancement treatments. A significant packaging ... enhancement ... display time interaction resulted for L* values (P < 0.001). Dark-cutting steaks enhanced with 0.2% rosemary and packaged in HiOx-MAP was lighter (P < 0.001; greater L* values) than other darkcutting treatments on d 5 of display. There were no differences (P = 0.34) in discoloration scores on d 5 among different dark-cutting treatments when steaks were packaged in HiOx- and CO-MAP. There was an aging period ... enhancement ... packaging interaction (P < 0.0033) for lipid oxidation. On d 0 of display, there were no differences (P = 0.54) in TBARS values between different aging periods and enhancement treatments. Dark-cutting steaks enhanced with 0.2% rosemary had lower (P < 0.001) TBARS values than 0.1% rosemary on d 5 when aged for 21 d and in HiOx- MAP. The results suggest that rosemary enhancement with CO- or HiOx-MAP has the potential to improve the surface color of dark-cutting beef.

The objective of the current study was to evaluate the effects of aging on myoglobin chemistry of dark-cutting beef. Ten USDA Choice (mean pH = 5.6; normal pH beef) and 10 no-roll dark cutter (mean pH = 6.4) strip loins were obtained from a commercial packing plant within 3 d of harvest. Loins were cut into 4 sections, vacuum packaged, randomly assigned to 0-, 21-, 42-, and 62-d aging at 2°C in the dark. Following aging, loin sections were cut into 25-cm-thick steaks and were used to determine bloom development, oxygen consumption (OC), metmyoglobin reducing activity (MRA), and lipid oxidation. Surface color readings were measured using a HunterLab Miniscan XE Plus spectrophotometer. A significant muscle type x aging time interaction resulted for OC (P < 0.001). Normal pH steaks declined more (P < 0.001) in OC during aging than dark-cutting beef. On d 0, dark-cutting beef had a greater OC (P < 0.001) than normal pH beef. There was a significant muscle type x oxygenation time x aging period interaction for L values, deoxymyoglobin (DeoxyMb), and oxymyoglobin (OxyMb). When dark-cutting sections were aged for 62 d, both 0 and 60 min bloom development L values were greater (P < 0.0001) than 0 min dark-cutting sections aged for 21 or 42 d. At all aging periods, normal pH beef had greater OxyMb content and lower DeoxyMb (P < 0.0001) during bloom development than dark-cutting beef. An aging period x muscle type interaction was significant for % overall reflectance (P = 0.0017) and absorbance (P = 0.0038). Dark cutting and normal pH beef loin sections aged for 62 d had greater reflectance (P < 0.0001) than 21 d. On d 0, dark-cutting beef had greater (P < 0.0001) MRA than normal pH beef. There were no significant (P = 0.14) differences in MRA between 42 and 62 d between dark-cutting and normal pH beef. Dark cutting steaks had lower thiobarbituric acid reactive substances values (P < 0.0001) than normal pH steaks. The results indicate that characterizing the myoglobin chemistry during aging will help to design strategies to improve appearance of high pH beef.

Recent reports of biovolatilisation of phosphorus and antimony by anaerobic bacteria and of leaching of phosphorus and antimony fire-retardant additives from PVC cot mattress covers, indicate that the polyurethane inner-foam of cot mattresses could be a site for generation of toxic gases of group 15 elements. A toxic gas hypothesis for sudden infant death syndrome (SIDS) involving polyurethane foam of cot mattresses was proposed and tested experimentally. Levels of antimony, phosphorus, arsenic and bismuth were determined at four sites for 44 SIDS and 50 control (no death) cot mattress foams. There was no evidence to suggest that the levels of these elements in cot mattress foam have a causal relation to SIDS. Leaching of antimony trioxide from PVC mattress covers could account for detectable levels of this element in 52% of the cot mattress samples analysed. Volatile forms of antimony, phosphorus, arsenic and bismuth was not detected in the headspace of mixed or monoseptic cultures of anaerobic bacteria containing polyurethane foam. Past microbial activity had given rise to involatile methylated species of antimony in some of the cot mattress foams tested (61%, n = 24). Abiotic oxidation of biogenic trimethylantimony together with physical adsorption of methylantimony forms to the polyurethane foam matrix could account for the apparent absence of \"escaped\" volatile antimony species in culture headspaces of incubation vial. There was no evidence to suggest that levels of trimethylantimony or total methylantimony forms in cot mattress foams have a causal relation to SIDS.

Influenza A virus (IAV) infection leads to variable and imperfectly understood pathogenicity. We report that segment 3 of the virus contains a second open reading frame (\"X-ORF\"), accessed via ribosomal frameshifting. The frameshift product, termed PA-X, comprises the endonuclease domain of the viral PA protein with a C-terminal domain encoded by the X-ORF and functions to repress cellular gene expression. PA-X also modulates IAV virulence in a mouse infection model, acting to decrease pathogenicity. Loss of PA-X expression leads to changes in the kinetics of the global host response, which notably includes increases in inflammatory, apoptotic, and T lymphocyte-signaling pathways. Thus, we have identified a previously unknown IAV protein that modulates the host response to infection, a finding with important implications for understanding IAV pathogenesis.

Completing 6 months of treatment for tuberculosis in children is a challenge. In this open-label trial involving 1204 children in sub-Saharan Africa and India, 4 months of antituberculosis therapy was noninferior to 6 months of therapy.