Novel nitrite-embedded packaging improves surface redness of dark-cutting longissimus steaks

Effect of Nitrite-Embedded Packaging Film on Growth of Listeria monocytogenes in Nitrite-free and Conventionally-cured Bologna Sausage

Listeria monocytogenes is a pathogen frequently associated with ready-to-eat (RTE) meat and poultry products. Nitrite is a key antimicrobial additive that can offer some degree of protection against L. monocytogenes when included in meat product formulations. The objectives of this study were to determine the potential of nitrite-embedded film to affect the growth of L. monocytogenes following postthermal processing of conventionally-cured and nitrite-free bologna. Two bologna treatment formulations, a conventionally-cured control formulation (CON) and a nitrite-free formulation (UCC), were manufactured, packaged in conventional (CF) or nitrite-embedded (NEF) film, inoculated with 3.5 log CFU/cm2 of a cocktail of L. monocytogenes strains, and stored at 10 ± 1 °C. CON-NEF and UCC-NEF treatments had significantly slower (P < 0.05) growth of L. monocytogenes than CON-CF and UCC-CF, with populations in UCC-CF (which contained no nitrite) increasing by 3.4 logs after 10 d of storage in UCC-CF and 3.6 logs after 50 d in CON-CF (which had formulated nitrite only), while in the NEF-packaged samples, with or without formulated nitrite, they did not exceed the inoculum level until after day 40. Initial (day 0) residual nitrite was significantly greater (P < 0.05) in the control formulation. Packaging in NEF, however, resulted in an increase of 27-28 ppm by day 3, regardless of formulation, after which it decreased rapidly. Results suggest NEF can be used as a post-lethality antimicrobial intervention in food safety intervention strategies, in both cured and uncured processed meat products.

Impact of nitrite-embedded packaging film on quality and sensory attributes of alternatively-cured and nitrite-free bologna

The objectives were to determine the effects of post-thermal processing nitrite-embedded film (NEF) packaging on the quality attributes of alternatively-cured (nitrite from celery juice powder (AC)) and nitrite-free bologna. Attributes evaluated included lipid oxidation, instrumental color, pigment concentration, and sensory properties such as cured meat flavor, aroma, and color. Three bologna formulations, each packaged with two packaging films were produced. A conventionally-cured control formulation (with nitrite from sodium nitrite; CON), a nitrite-free formulation (UCC), and an alternatively cured formulation (nitrite from cultured celery juice powder; AC) were packaged in conventional (CF) or nitrite-embedded (NEF) film. Instrumental a* values (measured during both light and dark storage at intervals of 7 or 14 days over 126 days of storage) and cured pigment concentration (measured at 14-day intervals over 84 days of storage) were significantly greater (P < 0.05) for the UCC-NEF treatment compared to its conventional film counterpart, UCC-CF. No significant differences (P > 0.05) for lipid oxidation (TBARS values) were observed with NEF. Trained sensory panelists, who evaluated samples at 14-day intervals over 70 days of storage, found significantly greater (P < 0.05) cured aroma, cured flavor, pink color and less off-flavor for uncured bologna packaged in NEF compared to conventional film. For the uncured bologna formulation, NEF packaging provided cured meat attributes comparable to the control formulation that included nitrite. This is the first time that cured aroma and flavor have been observed when nitrite from packaging film is added to a cooked meat product under anaerobic conditions.

Repackaging Nitrite-Embedded Dark-Cutting Steak in Aerobic Polyvinyl Chloride Film Decreases Surface Redness

The overall goal was to evaluate the effects of repackaging nitrite-embedded dark-cutting steaks in polyvinylchloride (PVC) film on surface color. Dark-cutting beef strip loins (n = 8; pH = 6.39) and USDA Low Choice beef strip loins (USDA Choice, n = 6; pH = 5.56) were selected at a commercial packing plant. Dark-cutting loins were bisected and randomly assigned to nonenhanced dark-cutting and enhanced dark-cutting with glucono delta-lactone and rosemary treatments. USDA Choice and nonenhanced dark-cutting steaks were vacuum packaged (VP) and served as controls, whereas enhanced dark-cutting steaks were packed in nitrite-embedded packaging (NP). Steaks from nonenhanced USDA Choice VP, nonenhanced dark-cutting VP, and enhanced dark-cutting NP loins were randomly assigned to 3, 6, or 9 d of dark storage.Following dark storage, steaks were repackaged in PVC and displayed for 6 d at 2°C. Instrumental color, visual color, and aerobic plate count were evaluated for all steaks. Enhanced dark-cutting steaks in NP increased (P &lt; 0.05) a* values compared with USDA Choice and nonenhanced dark-cutting VP during 24 h of dark storage. Enhanced dark-cutting steaks packaged in NP had greater a* and L* values (P &lt; 0.05) than nonenhanced dark-cutting VP steaks during dark storage. Upon repackaging the enhanced dark-cutting steaks from NP, nitric oxide myoglobin decreased (P &lt; 0.05) during the first 12 h of display. Loss of nitric oxide myoglobin corresponds with a darker red appearance, increased surface discoloration, and decreased a* values.There were no differences (P &gt; 0.05) in aerobic plate count between enhanced dark-cutting NP steaks and nonenhanced dark-cutting VP steaks after repackaging. In conclusion, NP improved surface redness; however, repackaging enhanced dark-cutting from NP steaks in PVC decreased color stability and redness of dark-cutting beef.

Effects of Enhancement and Modified Atmosphere Packaging on Flavor and Tenderness of Dark-Cutting Beef

The objective of this study was to evaluate the effects of rosemary/beef flavor enhancement and modified atmosphere packaging (MAP) on retail display color and palatability of beef longissimus lumborum muscle. Dark-cutting beef strip loins (n = 8; pH &gt; 6.0) and USDA Low Choice beef strip loins (n = 5) were selected from a commercial packing plant within 72 h of harvest. Dark-cutting strip loins were divided into 2 equal sections and randomly assigned to either nonenhanced or rosemary/beef flavor–enhanced treatments. Dark-cutting enhanced loins were injected to 110% of their green weight with a rosemary/beef flavor enhancement to attain 0.1% rosemary, 0.5% salt, and 0.55% beef flavor in the final product. Six 2.54-cm-thick steaks were cut from nonenhanced USDA Choice, nonenhanced dark-cutting, and enhanced dark-cutting strip loins and randomly assigned to one of 3 packaging treatments: vacuum packaging, carbon monoxide MAP (0.4% CO, 69.6% N, and 30% CO2), and high-oxygen MAP (80% O2 and 20% CO2). Following 3-d retail display, instrumental color measurements were recorded, and one steak from each packaging type was evaluated by a trained sensory taste panel and another used to measure Warner-Bratzler shear force. Enhanced dark-cutting steaks packaged in high-oxygen MAP and carbon monoxide MAP had greater a* values (P &lt; 0.0001) than dark-cutting steaks in vacuum packaging. Enhanced dark-cutting steaks were lighter (P &lt; 0.0001, greater L* values) than nonenhanced dark-cutting steaks. Nonenhanced dark-cutting steaks exhibited a lower (P = 0.03) overall juiciness compared to enhanced dark-cutting steaks. Enhanced and nonenhanced dark-cutting steaks were more tender (P = 0.002) than the USDA Choice steaks. Enhanced dark-cutting steaks had higher (P = 0.006) sour flavor in vacuum packaging than other packaging types. The results suggest that rosemary/beef flavor enhancement has the potential to improve the surface color of dark-cutting beef while improving or maintaining palatability.

Recent Updates in Meat Color Research: Integrating Traditional and High-Throughput Approaches

Deviation from a bright cherry-red color of fresh meat results in less consumer acceptance and either discounted or discarded products in the value chain. Tissue homeostasis changes immediately after exsanguination, leading to acidification of muscle. Any alteration in pH drop can influence both muscle structure and enzymatic activity related to oxygen consumption and the redox state of myoglobin. This review focuses on both fundamental and applied approaches to under-stand the effects of pH on biochemical changes, oxygen diffusion, and its impact on meat color. Recent updates utilizing high-throughput “omics” approaches to elucidate the biochemical changes associated with high-pH meat are also dis-cussed. The fundamental aspects affecting fresh meat color are complex and highly interrelated with factors ranging from live animal production to preharvest environmental issues, muscle to meat conversion, and numerous facets along the merchandising chain of marketing meat to consumers.

Effects of Aging, Modified Atmospheric Packaging, and Display Time on Metmyoglobin Reducing Activity and Oxygen Consumption of High-pH Beef

The objective of current research was to determine the effects of extended aging, modified atmospheric packaging (MAP), and display time on metmyoglobin reducing activity (MRA) and oxygen consumption (OC) of high-pH beef using pH sensitive methodology for MRA and OC. Ten normal-pH (mean pH = 5.6) and 10 high-pH loins (mean pH = 6.4) were vacuum packaged on d 3 postmortem and aged for 0, 21, 42, and 62 d at 2°C. Following aging, 2.0-cm-thick steaks were cut from each of the normal- and high-pH loin sections and packaged in either PVC film, high-oxygen (HiOx-MAP), or carbon monoxide modified atmospheric (CO-MAP) packaging. Surface color, OC, and MRA were measured on d 0 and 6 of the respective aging periods. Steaks in HiOx-MAP and CO-MAP had similar (P > 0.05) L* values, which were greater (P < 0.05) than high-pH steaks packaged in PVC film. On 21-d of aging, steaks with at both pHs in CO-MAP and HiOx-MAP had greater (P < 0.05) a* values than steaks packaged in PVC. As aging time increased, MRA decreased (P < 0.05) for steaks with normal- and high-pH when packaged in PVC and HiOx-MAP. Steaks with a high-pH in CO-MAP had greater (P < 0.05) MRA than steaks with a normal-pH in CO-MAP at all aging periods. Steaks with a high-pH had greater (P < 0.05) OC on d 0 and 6 than normal-pH steaks. Steaks with a normal-pH aged for 21 d and packaged in PVC and HiOx-MAP had greater (P < 0.05) lipid oxidation than high-pH steaks aged for 21 d and packaged in PVC and HiOx-MAP. After 62 d of aging and 6 d of display, the greatest color stability chemistry (based on MRA and OC for all package types) were: high-pH meat > normal-pH meat; thus the MRA and OC methodology was useful in relative comparison of packaged meat color stability differences due to pH.