Premature browning in cooked ground beef after modifying myoglobin

Some ground beef patties developed an internal, brown cooked color and looked well-done at temperatures as low as 131 ̊F, whereas normal patties were re d to pink. The premature brown color was not relate d to percent fat; patty compaction; animal source and maturity; pH (5.5 to 5.8); or concentrations of raw patty heme and nonhemeiron, myoglobin, and total pigment. Because oxidation-reduction potential and total reducing activities were higher (P<.05) and TBA numbers were lower (P<.05) in normal than prematurely brown patties, the brown color is apparently related to greater patty oxidation

Use of visual appearance as an indicator of degree of doneness in ground beef patties

Outbreaks of food-borne illness have emphasized the need for proper cooking of ground beef patties. Because of difficulties in measuring internal temperature of ground beef patties, visual indicators usually are used to estimate degree of doneness. As internal temperature increases from 130 to 170 ̊F, the internal appearance is expected to change from very red to brown and juice color from red to clear. Based on ground beef patties from three sources, we found that internal color over-estimated internal temperature. Expressible juice decreased in redness as internal temperature increased but did not run clear even at temperatures over 160 ̊F. Regardless, expressible juice color was a better indicator of degree of doneness than internal color

Factors affecting premature browning in cooked ground beef

Some ground beef patties developed an internal, brown cooked color and looked well-done at temperatures as low as 13 1EF, whereas normal patties were re d to pink. The premature brown color was not relate d to percent fat; patty compaction; animal source and maturity; pH (5.5 to 5.8); or concentrations of raw patty heme and nonhemeiron, myoglobin, and total pigment. Because oxidation-reduction potential and total reducing activities were higher (P<.05) and TBA numbers were lower (P<.05) in normal than prematurely brown patties, the brown color is apparently related to greater patty oxidation

Effects of modified atmosphere packaging and carcass chill rate on pork loins

Use of 10% oxygen in a modified gas atmosphere package resulted in more off-odor, higher microbial counts, and a less desirably colored loin and loin chops. Furthermore, it reduced chop display life and is not recommended

Bone-in pork loins: modified atmosphere packaging to extend shelf-life

Modified atmosphere packaging with 100% carbon dioxide was used to investigate changes in daily gas composition, as well as the influence of fat trim level and location of loin in the box on shelf life characteristics. Length of storage was the primary factor influencing shelf life of whole loins and their retail chops. Although microbial qualities was acceptable in loins stored up to d 19, sirloin and blade discoloration was obvious at 11-13 d. Storage for more than 11 d reduced the display life of retail chops to 1-2 d. Shelf life characteristics of bone-in pork loins were superior with this packaging system compared to more traditional systems

NK cells and monocytes modulate primary HTLV-1 infection

We investigated the impact of monocytes, NK cells, and CD8+ T-cells in primary HTLV-1 infection by depleting cell subsets and exposing macaques to either HTLV-1 wild type (HTLV-1WT) or to the HTLV-1p12KO mutant unable to infect replete animals due to a single point mutation in orf-I that inhibits its expression. The orf-I encoded p8/p12 proteins counteract cytotoxic NK and CD8+ T-cells and favor viral DNA persistence in monocytes. Double NK and CD8+ T-cells or CD8 depletion alone accelerated seroconversion in all animals exposed to HTLV-1WT. In contrast, HTLV-1p12KO infectivity was fully restored only when NK cells were also depleted, demonstrating a critical role of NK cells in primary infection. Monocyte/macrophage depletion resulted in accelerated seroconversion in all animals exposed to HTLV-1WT, but antibody titers to the virus were low and not sustained. Seroconversion did not occur in most animals exposed to HTLV-1p12KO. In vitro experiments in human primary monocytes or THP-1 cells comparing HTLV-1WT and HTLV-1p12KO demonstrated that orf-I expression is associated with inhibition of inflammasome activation in primary cells, with increased CD47 "don't-eat-me signal" surface expression in virus infected cells and decreased monocyte engulfment of infected cells. Collectively, our data demonstrate a critical role for innate NK cells in primary infection and suggest a dual role of monocytes in primary infection. On one hand, orf-I expression increases the chances of viral transmission by sparing infected cells from efferocytosis, and on the other may protect the engulfed infected cells by modulating inflammasome activation. These data also suggest that, once infection is established, the stoichiometry of orf-I expression may contribute to the chronic inflammation observed in HTLV-1 infection by modulating monocyte efferocytosis.SCOPUS: ar.jinfo:eu-repo/semantics/publishe