Effects of lactate and modified atmospheric packaging on premature browning in cooked ground beef patties

Our objectives were to determine the effects of lactate and modified atmosphere packaging on raw surface color, lipid oxidation, and internal cooked color of ground beef patties. Eight chubs (85% lean) were divided in half and each half was either assigned to the control (no lactate) or mixed with 2.5% lactate (w/w). Following treatment, patties were prepared and packaged in either vacuum, PVC (atmospheric oxygen level), high-oxygen (80% O₂ + 20% CO₂), or 0.4% CO (30% CO₂ + 69.6% N₂) and stored for 0, 2, or 4 days at 2 °C. After storage, raw surface color and lipid oxidation were measured and patties were cooked to either 66 °C or 71 °C. Lactate improved (p < 0.05) color stability of PVC, high-oxygen, and vacuum packaged raw patties, but had no effect (p > 0.05) on the a∗ values and visual color scores of patties in 0.4% CO. Lactate decreased (p < 0.05) lipid oxidation in all packaging atmospheres. Nevertheless, high-oxygen and PVC-packaged patties had more (p < 0.05) lipid oxidation than patties in CO and vacuum. Lactate had no effect (p > 0.05) on premature browning, whereas patties packaged in high-oxygen demonstrated premature browning. Conversely, cooked patties in 0.4% CO and vacuum were more red (p < 0.05) than both high-oxygen and PVC-packaged patties. Although lactate improved raw color stability, it did not minimize premature browning in cooked ground beef patties.     

Color stability of ground beef packaged in a low carbon monoxide atmosphere or vacuum

Ground beef was either packaged in an atmosphere of 0.4% CO, 30% CO₂, and 69.6% N₂ (CO-MAP) or vacuum. After storage (48 h, 2–3 °C), packages of CO-MAP and vacuum were opened and overwrapped with polyvinyl chloride. Other CO-MAP and vacuum packages were left intact. Packages were initially displayed for 7 days (2–3 °C). Intact packages were further displayed up to 35 days before being opened and displayed (1 or 3 days). Intact CO-MAP packaged ground beef was always more red than intact vacuum-packaged ground beef. Color was relatively stable for both types of intact packages over 35 days of display. Upon opening CO-MAP packaged ground beef, the red color decreased slower than in ground beef from vacuum packages.     

Packaging-specific influence of chitosan on color stability and lipid oxidation in refrigerated ground beef

We examined the influence of chitosan on lipid oxidation and color stability of ground beef stored in different modified atmosphere packaging (MAP) systems. Ground beef patties with chitosan (1%) or without chitosan (control) were packaged either in high-oxygen MAP (HIOX; 80% O₂ + 20% CO₂), carbon monoxide MAP (CO; 0.4% CO + 19.6% CO₂ + 80% N₂), vacuum (VP), or aerobic packaging (PVC) and stored at 1 °C. Chitosan increased (P < 0.05) redness of patties stored in PVC and CO, whereas it had no effect (P > 0.05) in HIOX. Chitosan patties demonstrated lower (P < 0.05) lipid oxidation than controls in all packaging. Control patties in PVC and HIOX exhibited greater (P < 0.05) lipid oxidation than those in VP and CO, whereas chitosan patties in different packaging systems were not different (P > 0.05) from each other. Our findings suggested that antioxidant effects of chitosan on ground beef are packaging-specific.     

Chitosan inhibits premature browning in ground beef

Our objective was to evaluate the effect of chitosan on premature browning in refrigerated ground beef patties stored in different packaging systems. Ground beef patties (15% fat) with chitosan (1% w/w) or without chitosan (control) were individually packaged either in vacuum (VP), aerobic packaging (AP), carbon monoxide modified atmosphere packaging (LO-OX; 0.4% CO+19.6% CO(2)+80% N(2)), or high-oxygen modified atmosphere packaging (HI-OX; 80% O(2)+20% CO(2)), and stored for 0, 1, or 3 days at 1°C. At the conclusion of storage, raw surface redness was evaluated, patties were cooked to internal end-point temperatures of either 66°C or 71°C, and internal cooked color was measured. The incorporation of chitosan increased (P<0.05) the interior redness of patties stored in AP, VP, and LO-OX, but not in HI-OX. The results of the present study suggest that the incorporation of 1% chitosan minimizes premature browning in ground beef patties stored under AP, VP, and LO-OX.     

Color stability and reversion in carbon monoxide packaged ground beef

This study investigated the relationship between length (1, 2, 4, or 6 days) of exposure to carbon monoxide (CO) and the subsequent rate of loss of carboxymyoglobin color during display (0, 24, 48, 72 h) after repackaging in an oxygen permeable polyvinyl chloride (PVC) overwrap. In addition, the ability of CO to cause color reversion of metmyoglobin to carboxymyoglobin in brown colored, aged (4 days, PVC) or low oxygen-induced (2 days, (LOX-MAP) ground beef was studied. Extending CO exposure time increased overall mean redness. However, overall mean redness decreased after packages were opened. Day 6 exposed ground beef only maintained about 1.5 Minolta a∗ units higher than day 1 exposed after opened 72 h. The color of brown ground beef was converted to carboxymyoglobin upon exposure to carbon monoxide, regardless of how the initial brown color was formed. This color changes was relatively faster in LOX-MAP packaged ground beef compared to that formed by aging in PVC. Although color reversion is possible, consideration should be given to the microbiological status of the ground beef at the time of CO packaging.     

The effects of modified atmosphere gas composition on microbiological criteria, color and oxidation values of minced beef meat

This paper reports the effects of modified atmosphere gas compositions with different concentrations of CO(2)/O(2)/N(2) on color properties (L*, a* and b* values), oxidation stability (TBARS value) and microbiological properties of minced beef meat stored at +4 °C. Sampling was carried out on the 1st, 3rd, 5th, 7th, 9th, 11th and 14th day of storage. The gas mixtures used were as follows: (i) %30O(2) + %70CO(2) (MAP1), (ii) %50O(2) + %50CO(2) (MAP2), (iii) %70O(2) + %30CO(2) (MAP3), (iv) %50O(2) + %30CO(2) + %20N(2) (MAP4), and (v) %30O(2) + %30CO(2) + %40N(2) (MAP5). Control samples (AP) were packaged under atmospheric air. Pseudomonas, lactic acid bacteria, Brochothrix thermosphacta, and Enterobacteriaceae members were monitored. Among these five modified atmosphere gas compositions, the best preservation for minced beef meat was in MAP4 gas combination maintaining acceptable color together with oxidation stability and acceptable microbial loads until the end of storage period of fourteen days.     

Effects of dietary vitamin E supplementation and packaging on the colour stability of sliced pasteurized beef ham

The effect of supplementation of vitamin E (2025 IU animal⁻¹ day⁻¹) in the diet of beef bulls on the colour stability of pasteurized beef ham was studied. Control and enriched diets were provided for the last 136 days before slaughter. Pasteurized hams were manufactured from Mm. semitendinosus from eight animals per dietary group. Half of the samples of sliced ham from control (CON) and supplemented (SUP) bulls were packaged under vacuum (VAC) and half in low-oxygen modified atmosphere packs (FOG, gas mixture: CO₂/N₂=50/50). The packages were kept under constant illumination for 28 days at 8°C. During storage, the number of colony-forming units (CFU) reached a maximum of 5x10⁷ g⁻¹. The microflora was dominated by lactic acid bacteria. The supplementation with vitamin E showed no effect on microbial growth. Lipid oxidation was stable during storage. A significant difference between both dietary groups was detected for the decrease in the redness values during storage. Redness values of CON vacuum-packaged samples decreased (P < 0.01) with time, whereas those for the SUP products only tended to decrease. The redness values of FOG-packed ham were higher than those of VAC-packed ham at the end of the display period, irrespective of the dietary group. Overall, colour appeared to be more stable in the FOG-packed products than in the VAC-packed products. It can be concluded that dietary supplementation of bulls with vitamin E appears to offer only a minor improvement in colour stability over current feeding regimens when the Mm. semitendinosus are used to make cured, pasteurized ham-type products.     

Colour of ground beef as influenced by raw materials,addition of sodium chloride and low oxygen packaging

The study aimed at examining the effects of freezing of raw materials, holding time for fresh raw materials post mortem and addition of 0.5–1.0% NaCl on the colour of ground beef under low oxygen (O₂) modified atmosphere storage. The samples were exposed to 0.1–3.0% O₂ at 4 °C for up to 10 days, and analysed for O₂ concentrations, instrumental and visual colour. Residual O₂ in the headspace of the packages oxidizes myoglobin and discolours the meat. Meat may have the ability to scavenge residual O₂, and ground beef differs from intact muscles by having a much higher capacity for O₂ consumption. In this experiment, the use of frozen/thawed raw materials and addition of NaCl both decreased the rate of O₂ consumption and increased discolouration. Using raw materials from 2 days rather than 7 days post mortem greatly increased the rate of removal of O₂ and improved redness. In low O₂ packaging, ground beef preferably should be stored for at least 2 days in an atmosphere with less than 0.1% residual O₂ to produce a purple pigment predominantly consisting of deoxymyoglobin.     

Effects of lactate/phosphate injection enhancement on oxidation stability and protein degradation in early postmortem beef cuts packaged in high oxygen modified atmosphere

The influence of lactate/phosphate enhancement on meat color and lipid oxidation stability, tenderness, protein degradation, and protein aggregation of early postmortem beef muscles packaged in a high oxygen modified atmosphere packaging (HiOx-MAP; 80% O₂, 20% CO₂) were studied. At 24 hr postmortem, three bovine muscles (longissimus, semimembranosus, and adductor; n = 10, respectively) were enhanced (10% injection rate) with either lactate (2.5%)/phosphate (0.3%) solution or water, packaged in HiOx-MAP, stored 9 days at 1 °C, and then displayed for 7 days at 1 °C. The lactate/phosphate injection significantly improved color stability (higher a* values) of all three bovine muscles throughout display period. Accumulation of lipid oxidation determined by 2-thiobarbituric acid-reactive substances values was also decreased (P < 0.05) in the lactate/phosphate injection compared to the water treatment during storage and display periods. The objective tenderness values of longissimus and semimembranosus were also improved (P < 0.05) by the lactate/phosphate enhancement treatment compared to the water treatment based on star probe measurement. There were no significant differences found in desmin and troponin-T degradation, or oxidative cross-linking of myosin between treatments. The results suggest that lactate/phosphate enhancement has beneficial effects on color and lipid oxidation stability, and tenderness development of beef cuts under HiOx-MAP conditions.     

Effects of storage under a modified atmosphere on the microbiological and organoleptic qualities of ground beef prepared from pasteurized manufacturing beef

A 40‐kg lot of manufacturing beef, i.e. meat used for the production of ground beef products, was collected at a beef packing plant. The lot was divided into two batches. One batch was pasteurized by immersion in water at 85 °C for 60 s, the other batch was not pasteurized. Both batches were then ground. The ground meat was packed in overwrapped trays, which were master packaged under a modified atmosphere of 70% O₂ : 30% CO₂. The master packs were stored at 2 °C for up to 12 days. At the time of pack preparation and at 2‐day intervals, a master pack containing pasteurized and another pack containing unpasteurized meat, were opened and retail packs from each master pack were displayed at 4 °C for 3 days. Samples for microbiological analysis were obtained at the times of opening master packs and at the end of display. Displayed meat was assessed daily for colour, discoloration and retail appearance, and for odour intensity and acceptability at the end of display. After either a period of storage or a period of storage and display, the numbers of bacteria recovered from pasteurized meat were less than the numbers recovered from unpasteurized meat. The colour of pasteurized meat was perceived as being paler than that of unpasteurized meat, but discoloration was similar or less, and retail appearance was similar or better for pasteurized than unpasteurized meat at all times. The odours of displayed, pasteurized meat were generally somewhat less intense and more acceptable than those of unpasteurized meat. The findings indicate that pasteurization of manufacturing beef to improve the microbiological safety of ground beef provides a product of acceptable appearance and enhanced stability during storage under a modified atmosphere and subsequent display in air.     

Cow biological type affects ground beef colour stability

To determine the effects of cow biological type on colour stability of ground beef, M. semimembranosus from beef-type (BSM) and dairy-type (DSM) cows was obtained 5 d postmortem. Three blends (100% BSM, 50% BSM + 50% DSM, 100% DSM) were adjusted to 90% and 80% lean points using either young beef trim (YBT) or beef cow trim (BCT), then packaged in high oxygen (High-O₂; 80% O₂) modified atmosphere (MAP). The BSM + YBT patties had the brightest colour initially, but discoloured rapidly. Although DSM + BCT patties had the darkest colour initially, they discoloured least during display. Metmyoglobin reducing ability of ground DSM was up to fivefold greater than ground BSM, and TBARS values of BSM was twofold greater than DSM by the end of display (4 d). Though initially darker than beef cow lean, dairy cow lean has a longer display colour life and may be advantageous to retailers using High-O₂ MAP.     

Microbiological and chemical quality of ground beef treated with sodium lactate and sodium chloride during refrigerated storage

The effects of sodium lactate (NaL) and sodium chloride (NaCl), either alone (30 g/kg) or in combination (20+20 g/kg), on the microbiological and chemical quality of raw ground beef during vacuum-packaged storage at 2°C were investigated. The results showed that addition of NaL alone or in combination with NaCl significantly delayed the proliferation of aerobic plate counts, psychrotrophic counts, lactic acid bacteria and Enterobacteriaceae and extended the shelf life of the product up to 15 and 21 days, respectively, versus 8 days only for control. Over the storage time (21 days), NaL maintained the ground beef at almost constant pH, while the pH of control or NaCl-treated samples significantly decreased. Lipid oxidation (TBA value) was not affected by addition of NaL. At storage day 21 however, TBA values of both NaL-treated (0.309) and control (0.318) samples were significantly lower than those of samples treated with NaCl (0.463). The combination of NaCl with NaL significantly reduced the oxidative changes caused by NaCl (0.384 versus 0.463). Therefore, NaL alone or in combination with NaCl could be utilized successfully to reduce the microbial growth, maintain the chemical quality, and extend the shelf life of ground beef during refrigerated storage.     

Influence of storage period and packaging method on sliced dry cured beef "Cecina de Leon": Effects on microbiological, physicochemical and sensory quality

Quality aspects of sliced dry-cured beef “Cecina de León” preserved in vacuum and gas mixtures (20%/80% CO₂/N₂ and 80%/20% CO₂/N₂) were studied. The evolution of microbiological, physicochemical and sensory parameters were analysed during storage (210 days) at 6 °C. Although microbial counts at 60 days of the gas-packaged samples were lower than the vacuum-packed ones, they were never higher than the spoilage limit (7 log ufc/g). A slight increase (p < 0.05) in pH was observed throughout storage of “Cecina de León” packaged under vacuum and in gas mixtures. However, a decrease (p < 0.05) in a_w was observed during storage of “Cecina de León” packaged under vacuum but a_w did not vary (p > 0.05) during storage in the gas-packaged samples. No changes were observed (p > 0.05) in lightness (L^*), redness (a^*) and yellowness (b^*) in vacuum and gas packaged samples during storage. However, sensorially evaluated colour showed lower values in gas packaged samples during 30 days storage. This difference was decisive in establishing the shelf-life of “Cecina de León” slices preserved in gas mixtures (20%/80% CO₂/N₂ and 80%/20% CO₂/N₂). Therefore, from a microbiological point of view, gas mixtures are more effective in extending the shelf-life of “Cecina de León” slices. It is concluded that vacuum packaging allows longer storage than gas-packaging as it maintains a good visual appearance of “Cecina de León”, the main parameter in consumers’ perception of meat quality.     

Characterization and identification of yeasts from fresh and spoiled ground beef

From 28 samples of fresh and 4 of spoiled ground beef, 197 yeast isolates were obtained. Following identification, 79 strains resulted representing five genera with the genus Candida accounting for 82% of the strains and 61% of the identified species. Other genera found were Rhodotorula, Torulopsis, Trichosporon, and Cryptoccus. With one exception, only Candida was recovered from spoiled beef. The findings indicate that the yeast flora of fresh ground beef is characterized almost exclusively by Candida. Although not definitive, it appears that C. lipolytica, the most frequently isolated species, and C. zeylanoides are more indigenous to ground beef than any of the other 21 species identified.     

Effects of packaging method and storage time on the chemical, microbiological, and sensory properties of Turkish pastirma - A dry cured beef product

The effects of packaging method (aerobic packaging (AP), vacuum packaging (VP) or modified atmosphere packaging (MAP)), the form of pastirma (sliced or non-sliced) and storage time (0, 15, 30, 60, 90 or 120 days) on the chemical, microbiological and sensory properties of a Turkish pastirma were investigated. Overall, MAP preserved chemical, microbiological and sensory properties of Turkish pastirma better than AP or VP. Very high correlation coefficients (almost all >0.90) were observed between subjective quality parameters (sensory properties) and objective quality parameters (TBARS, hexanal content, L^*, a^*, and b^*), which suggests that sensory panel was able to determine the quality changes over storage time precisely. Based on the results of this study, MAP should be the preferred choice of packaging in order to preserve overall quality of Turkish pastirma and its implication for pastirma packaging may increase pastirma’s current share in the processed meat product market.     

Omega-3 fatty acids affected human perception of ground beef negatively

The objective was to determine the impact of increasing levels of Eicosapentaenoic acid (EPA; C20:5n3) and Docosahexaenoic acid (DHA; C22:6n3) on beef palatability. Two commercial supplements of EPA and DHA were added to 85% lean ground beef patties (176.2 ± 3.76 g) with different levels (0, 0.3, 0.4, 0.5, 0.6, 0.7, and 1% as-is). Olive oil was added so that all patties contained 1% added lipid. A control treatment was also prepared with no supplement or olive oil. Sensory evaluation and fatty acid analysis was conducted. Ground beef flavor decreased linearly (P<0.001) with increasing levels of EPA and DHA. Off-aroma and off-flavor increased linearly and then plateaued with increasing levels of EPA (P<0.0001). In conclusion, EPA had a greater negative impact on beef palatability than DHA. Also, the panelists were more sensitive to EPA in off-flavor perception than off-aroma.     

Rapid monitoring of the spoilage of minced beef stored under conventionally and active packaging conditions using Fourier transform infrared spectroscopy in tandem with chemometrics

Fourier transform infrared (FTIR) spectroscopy was exploited to measure biochemical changes within fresh minced beef in an attempt to rapidly monitor beef spoilage. Minced beef packaged either aerobically, under modified atmosphere and using an active packaging were held from freshness to spoilage at 0, 5, 10, and 15 °C. Frequent FTIR measurements were collected directly from the sample surface using attenuated total reflectance, in parallel the total viable counts of bacteria, the sensory quality and the pH were also determined.     

Evaluation of cholesterol and lipid oxidation in raw and cooked minced beef stored under oxygen-enriched atmosphere

Oxygen-enriched modified atmosphere packaging (MAP) represents an important means to stabilize meat colour but may lead to an increase in lipid oxidation, influencing the acceptability and safety of the product. In this work, the effect on cholesterol and lipid susceptibility to oxidation was investigated in commercial minced beef held under MAP (80% O(2)/20% CO(2)). Cholesterol oxidation products (COPs), peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) were determined, before and after pan frying, at 1, 8 and 15 days since packaging under refrigerated storage (3-4°C). 7α-Hydroxycholesterol, 7β-hydroxycholesterol and 7-ketocholesterol were the more abundant COPs identified. COPs significantly increased in raw beef during storage: after 1, 8 and 15 days since packaging COPs were at the levels of 10.4, 30.7 and 60.5μg/g of fat, respectively. Cooking did not affect cholesterol oxidation in freshly packaged minced beef but led to a rise in COPs amount with respect to raw muscle after 8 and 15 days of storage. The trend in cholesterol oxidation reflected the progressive increase in lipid peroxidation rate brought by MAP conditions.     

Antioxidative activity of carnosine in gamma irradiated ground beef and beef patties

The activity of carnosine as a natural antioxidant in gamma irradiated ground beef and beef patties was studied. Samples of ground beef, in the absence and presence of 0.5% or 1.0% carnosine, as well as raw and cooked beef patties prepared with 1.5% salt (NaCl), in the absence and presence of 0.5% or 1.0% carnosine, were gamma irradiated at doses of 0, 2, and 4 kGy. The extent of oxidation in irradiated and non-irradiated samples of ground beef and raw beef patties was then determined during refrigerated (4 ± 1 °C) and frozen (−18 °C) storage, while determined for cooked beef patties during refrigerated storage only. Moreover, the determination of metmyoglobin (MetMb) accumulation and sensory evaluation for the visual color were carried out for samples of ground beef and raw patties. The results indicated that salt or salt and cooking accelerated the oxidative processes and significantly increased the peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) in the prepared non-irradiated samples. However, salt slowed down the accumulation of MetMb in raw patties. Irradiation treatments and storage in the absence of carnosine significantly (P < 0.05) increased the PV and TBARS in samples, at higher rates in salted or salted and cooked beef. Moreover, irradiation and storage significantly (P < 0.05) increased the formation of MetMb in ground beef and raw patties in the absence of carnosine. Addition of carnosine significantly (P < 0.05) reduced the oxidative processes and MetMb formation (proportionally to the used concentration) in samples post-irradiation and during storage. Furthermore, carnosine exerted significant efficacy in maintaining an acceptable visual red color post-irradiation and during storage of ground beef and raw patties. These results demonstrate that carnosine can be successfully used as a natural antioxidant to increase the oxidative stability in gamma irradiated raw and cooked meat products.     

Antimicrobial activity of soy edible films incorporated with thyme and oregano essential oils on fresh ground beef patties

Antibacterial activity of soy protein edible films (SPEF) incorporated with 1, 2, 3, 4 and 5% oregano (OR) or thyme (TH) essential oils was evaluated against Escherichia coli, E. coli O157:H7, Staphylococcus aureus, Pseudomonas aeruginosa and Lactobacillus plantarum by the inhibition zone test. Effects of SPEF containing 5% OR and TH or a mixture of OR + TH (ORT) were also tested on fresh ground beef during refrigerated storage (at 4 °C). OR and TH incorporated SPEF exhibited similar antibacterial activity against all bacteria in inhibition zone test. While E. coli, E. coli O157:H7 and S. aureus were significantly inhibited by antimicrobial films, L. plantarum and P. aeruginosa appeared to be the more resistant bacteria. SPEF with OR, ORT, and TH did not have significant effects on total viable counts, lactic acid bacteria and Staphylococcus spp. when applied on ground beef patties whereas reductions (p < 0.05) in coliform and Pseudomonas spp. counts were observed.