Improvement of shelf-life of buffalo meat using lactic acid, clove oil and vitamin C during retail display

Buffalo meat steaks dipped in either (1) distilled water (control), (2) lactic acid (LA), (3) LA + clove oil (clove), or (4) LA + clove + vitamin C (Vit C) were displayed at 4 ± 1 °C, illuminated by a standard fluorescent lamp. The pH, 2-thiobarbituric acid reactive substances (TBARS), instrumental colour (CIE L^∗, a^∗, b^∗), aerobic plate counts (APC), psychrotrophic counts (PPC), coliform counts and sensory colour and odour were determined up to 12th day of display at 3 days interval. Results showed that, all the treatments have significantly (P < 0.05) reduced the TBARS values compared to control. Among treatments, use of LA + clove has exhibited significantly (P < 0.05) lowest TBARS values throughout display period than others. Buffalo meat steaks treated with either LA + clove or LA + clove + Vit C had significantly (P < 0.05) lower APC, PPC and coliform counts than control or LA treated samples. LA + clove + Vit C treated samples maintained significantly (P < 0.05) higher a^∗ and b^∗ values during display as well as improvement in sensory colour and odour than others. Treatment with either LA + clove or LA + clove + Vit C extended the display life of buffalo meat steaks at 4 ± 1 °C. There appears to be a significant advantage to using LA + clove or LA + clove + Vit C over LA alone.     

Shelf life of beef from local Spanish cattle breeds stored under modified atmosphere

Beef steaks from six Spanish cattle breeds (Asturiana de los Valles, Morucha, Parda Alpina, Pirenaica, Rubia Gallega and Retinta) were packaged under modified atmosphere (60% O(2), 30% CO(2) and 10% N(2)). Water loss, pH, thiobarbituric acid values (TBA), aerobic plate counts, lactic acid bacteria and Enterobacteriaceae counts, CIE L*a*b* colour values and the sensory properties of odour and colour were recorded before packaging (day 0) and after 5, 10 and 15 days of storage. A significant interaction (P<0.05) between breed and storage time was found for all variables, except water loss. Values of pH were between 5.3 and 5.6; maximum water loss (2.64%) was reached after 10 days of storage; aerobic plate counts, lactic acid bacteria and Enterobacteriacea counts were lower than 10(7) CFU/g, and L* increased with storage time while a* decreased (P<0.05). The maximum shelf life of beef assessed by sensory evaluation (regarding colour and odour degradation) was between days 5 and 10 in meat from Retinta breed and between days 10 and 15 in meat from the other breeds, shelf life was probably limited by lipid oxidation.     

The colour and colour stability of beef Longissimus dorsi and Semimembranosus muscles after effective electrical stimulation

The influence of effective low voltage electrical stimulation (ES) of beef on the colour and colour stability of longissimus dorsi (LD) and semimembranosus (SM) muscles, during storage and retail display was studied by tristimulus colorimetry and reflectance spectrophotometry. ES had no significant effect on the colour of the LD muscles, but some significant effects on SM muscles of ultimate pH 5·5-5·7. Three hours after slicing into steaks at 5 days post mortem, stimulated SM muscles had a paler/lighter colour than non-stimulated controls. During a retail display of 3 days, all steaks exhibited a loss of colour quality manifested in loss of redness and decreases in both hue and chroma (saturation). These changes were most marked in the stimulated SM muscles, and analysis indicated that they were due almost exclusively to the formation of metmyoglobin (metMb). Ageing the meat, as primals cuts, for 33 days at 0°C led to no significant differences in the perceived colour three hours after slicing. The colour changes observed during the 3-day retail display of steaks occurred more rapidly in both (ES and non-ES) 33 day-aged samples than in the 5 day-aged ones. The result of this was that the colour stability of non-stimulated steaks prepared at 33 days was similar to that of ES steaks prepared fresh (5 day post mortem). In SM muscles of pH 5·8-6·0 the apparent differences in colour of the ES and non-ES samples were not significant. However, meat of pH > 5·8, although darker than meat of lesser pH, had less tendency to form metmyoglobin during retail display.

The present work also confirmed that seemingly small differences in display conditions, especially temperature, have a marked effect on metmyoglobin formation.     

Effect of carnosine preblending on the quality of ground buffalo meat

A study was conducted on carnosine preblending at 0%, 0.5%, 1.0% and 1.5% levels with ground buffalo meat obtained from spent, adult, male Murrah buffalo carcasses, to identify the level of carnosine required for improving the quality of the meat during refrigerated storage at 4 ± 1 °C. It was observed that meat samples containing 1.0% and 1.5% carnosine significantly inhibited metmyoglobin formation and brown colour development. Carnosine also improved meat pH, and water-holding capacity and lowered cooking loss and 2-thiobarbituric acid-reacting substances (TBARS) values as compared to control sample. Carnosine also improved desired visual colour and odour, and gave higher LTCU ‘R’ and chroma of meat samples. Visual colour was inversely correlated with metmyoglobin, aerobic mesophiles and psychrotrophs plate count, and odour was inversely correlated with TBARS values. Use of 1.0% carnosine for preblending extended the shelf life of ground buffalo meat up to 8 days under refrigerated storage.     

Extension of the display life of lamb with an antioxidant active packaging

Fresh lamb steaks were treated with three different preparations of natural antioxidants: one group was packaged with a rosemary active film, the second group was packaged with an oregano active film, and the third group was sprayed on the meat surface with a rosemary extract before packaging in a high-oxygen atmosphere. Samples were stored under illumination at 1 ± 1 °C for 13 days. Metmyoglobin formation, lipid oxidation (TBARS), instrumental colour (CIE a^*), psychrotrophic bacterial counts (PCA), sensory discolouration and off-odour were determined. The use of a rosemary extract, a rosemary active film or an oregano active film resulted in enhanced oxidative stability of lamb steaks. Active films with oregano were significantly more efficient than those with rosemary, exerting an effect similar to that of direct addition of the rosemary extract; in fact, they extended fresh odour and colour from 8 to 13 days compared to the control.     

Effect of ascorbic acid and alpha-tocopherol on storage stability of beef steaks

Fresh beef loin steaks were dipped in solutions of (1) 70% ethyl alcohol (EtOH). (2) 70% EtOH containing 3% -ascorbic acid (AsA), (3) 70% EtOH containing 0·08% --tocopherol (Toc) and (4) 70% EtOH containing 3% AsA plus 0·08% Toc for 20 s, then drained for 10 s. Control samples received no dip treatment. After 3, 6, 9 and 13 days of storage at 4°C, the samples were evaluated for MetMb formation, TBA number and viable bacterial count. The beef steaks given AsA treatment maintained an acceptable meat colour for 13 days of storage. The TBA numbers of samples dipped in EtOH containing AsA stored for 13 days were significantly lower than those of controls, and in samples dipped in solutions without AsA. At 9 and 13 days of storage, the AsA plus Toc-treated samples gave lower TBA numbers than the samples given AsA treatment only. Viable bacterial counts were not affected by AsA, Toc or AsA plus Toc treatment. Beef loin steaks dipped in EtOH solution maintained a viable bacterial count of 10⁶ after 13 days of storage.     

Display life of sheep meats retail packaged under atmospheres of various volumes and compositions

Longissmus dorsi loins were removed from Suffolk cross-breed lambs (4–9 months) and hoggets (15–20 months). The effect of package gas composition was investigated by packaging loins with gas mixtures containing 80:20:0, 60:20:20 and 60:40:0/O₂:CO₂:N₂ with a 2:1 headspace to meat volume ratio. The most effective gas mixture for prolonging shelf-life was used to study the effect of different headspace to meat volume ratios. Loins were packaged with a headspace to meat volume ratio of 2:1, 1.5:1 or 1:1. All modified atmosphere (MA) packs were held under refrigerated display conditions (4 °C, 616 lx) for 12 days. Loins were assessed for microbial, oxidative and colour stability and headspace composition every 3 days. The 80:20:0/O₂:CO₂:N₂ gas composition and the 2:1 headspace to meat volume ratio was the most effective packaging combination at maintaining and prolonging the attractive red colour of MA packaged lamb and hogget meat. 80:20:0/O₂:CO₂:N₂ resulted in significantly (p<0.01) higher Hunter a values in lamb. The 2:1 ratio gave higher visual assessment values in lamb and higher Hunter ‘a' values for hogget meat throughout the trial. The 2:1 ratio was the most effective at decreasing Pseudomonas and increasing the numbers of lactic acid bacteria in the total microbial load in both lamb and hogget meat. Lipid oxidation in lamb and hogget meat occurred at a slower comparative rate than discolouration or microbial growth and was not the major determinant of shelf-life. The 2:1 headspace to meat volume ratio was most effective at maintaining the initial gas mix in both lamb and hogget MA packs.     

Effect of acid decontamination of beef subprimal cuts on the microbiological and sensory characteristics of steaks

Beef strip loins were decontaminated by spraying with solutions of various food grade acids (1.0% lactic acid, 1.0% acetic acid and an acid mixture containing 1.0% lactic acid, 2.0% acetic acid, 0.25% citric acid and 0.1% ascorbic acid) followed by vacuum packaging and storing at 4 ± 1°C. Initially and at days 3 and 6 of display in polyvinyl chloride (PVC) film, aerobic plate counts (APCs) of steaks fabricated from the acid treated loins that were stored for 0, 14, 28, 42, 56, 70 and 84 days were not significantly different (P > 0.05) from the APCs of steaks fabricated from control loins.     

A bacteriocin from Carnobacterium piscicola for the control of Listeria monocytogenes in vacuum-packaged meat

The purpose of this study was to determine the inhibitory capacity of a bacteriocin-like substance produced by Carnobacterium piscicola L103 against Listeria monocytogenes , when inoculated into vacuum-packaged meat. The bacteriocin was partially purified by ammonium sulfate precipitation and gel filtration on Sephadex G-25, followed by lyophilization. Beef steaks were inoculated with the bacteriocin and a sensitive strain of L. monocytogenes . The vacuum-packaged meat was stored at 4°C and microbial analyses were carried out every 7 days, over 21 days. Results showed that in the control steaks, without bacteriocin, counts of L. monocytogenes stayed at the initial inoculation level during the complete storage period. The naturally growing lactic acid bacteria (LAB) reached log 7·4 cfu cm⁻²after 14 days of storage and no inhibitory effect on the growth of the LAB was observed in the presence of the bacteriocin. The pH of the meat dropped from 5·7 to 5·0 in the inoculated as well as in the control samples, while colour and odour remained acceptable up to 14 days of storage. On the meat inoculated with bacteriocin, L. monocytogenes was completely inhibited after 14 days of storage at 4°C. It was concluded that the use of the inhibitory substance from C. piscicola L103 could be an important contribution to meat safety, when inoculated into vacuum-packaged meat.     

Shelf life of fresh foal meat under MAP, overwrap and vacuum packaging conditions

The objective of this study was to investigate the physico-chemical properties, the microbial counts and the sensory properties' changes of foal steaks packed under various conditions. The experimental packaging systems were: (i) vacuum packaging (VP), (ii) overwrap packaging and (iii) two modified atmosphere packaging methods (MAP): high O(2) MAP (80% O(2)+20% CO(2)) and low O(2) MAP (30% O(2)+70% CO(2)). The meat was stored at 2°C during 14days and tested for pH, colour, lipid and protein oxidation, microbial counts and sensory assessment of odour, colour and appearance. Of the two MAP, overwrap and VP, both MAP were the most effective treatments for the inhibition of the total viable counts (TVC), Pseudomonas spp., psychrotrophic aerobic bacteria, lactic acid bacteria, Enterobacteriaceae as well as moulds and yeast. According to the sensory evaluation, foal steaks packed under overwrap and MAP treatments resulted unacceptable after 7days of storage, whereas the vacuum-packed meat was still acceptable. Moreover, the redness value decreased significantly (P<0.001) with all treatments during the storage time, except for the vacuum packs, which increased significantly (P<0.001). Finally, foal steaks from overwrap packaging and MAP conditions had a greater increase of TBAR'S values and carbonyl content during the storage time. High O(2) levels affected foal meat quality negatively, while anaerobic conditions extended the meat's shelf life up to 14days.     

Presensitization of microorganisms by acid treatments to low dose gamma irradiation with special reference to Bacillus cereus

Effect of acid presensitization to low dose gamma irradiation on Bacillus cereus in sheep/goat meat stored at refrigeration temperature was assessed. Food grade organic acids (viz. propionic, lactic and acetic acids) were used as presensitizers followed by treatment with 1, 2 and 3 kGy irradiation doses (Co(60)). Two percent acetic acid plus 3 kGy irradiation elicited most effective to lower the total viable count and B. cereus count. Combination of treatments availed to reduce the dose required for elimination of radioresistant B. cereus and also masked the irradiation odour developed due to radiolysis. The study also revealed substantial increase in shelf life of mutton after combination treatment than single treatment without any adverse effect on acceptability of meat.     

Effect of food grade organic acids on inoculated S. aureus, L. monocytogenes, E. coli and S. Typhimurium in sheep/goat meat stored at refrigeration temperature

Sheep/goat forequarters procured from freshly slaughtered animals were decontaminated with hot water and inoculated with Staphylococcus aureus, Listeria monocytogenes, Escherichia coli and Salmonella typhimurium. The forequarters were individually spray washed with 2% lactic acid and 1.5% acetic + 1.5% propionic acid combination. Total viable count (TVC) of the treated meat samples was reduced by about 0.52 and 1.16 log units with marginal changes in colour and odour scores. Inoculated organisms were found to be highly sensitive to acid combination treatment as compared to lactic acid alone. Shelf-life of acid and acid combination treated samples was increased to 8 and 11 days as against 3 days in untreated samples. Carcass washing with acid alone or acid combination was found to be suitable for extension of shelf-life and improvement in the sensory and microbiological quality of meat.     

Influence of different gas compositions on the short-term storage stability of mother-packaged retail-ready lamb packs

Longissmus dorsi muscles were removed from Suffolk cross-breed lambs (aged 4-9 months) and cut into steaks. Lamb steaks were over-wrapped on trays and placed in vacuum pack bags. Bags were divided into 3 groups and flushed with gas mixtures containing 100:0, 90:10 or 80:20/CO(2):N(2). Mother packed lamb bags were stored for 4 days (T2) and 7 days (T3), respectively, in darkness at 4 °C, prior to retail display. The effect of aerobic packaging alone on lamb meat quality was used as the control (T1). Under retail display, all over-wrapped trays were held under refrigerated conditions (4 °C, 616 lx) for up to 8 days. Steaks were assessed for microbial growth, oxidative and colour stability as well as pH every 2 days. Mother-packing in 100:0/CO(2):N(2) was the most effective way of extending the storage life of retail ready lamb prior to display, particularly over longer storage periods. TVCs for T3 lamb meat using all gas compositions remained below 2.0×10(6) CFUs/g meat up until day 6 compared to day 4 in both T1 and T2 lamb. Lipid oxidation in lamb mother-packed for 7 days occurred at a faster comparative rate than discolouration and microbial growth and was the major determinant of shelf-life. However, under simulated retail display in aerobic packages, TBARS values did not increase significantly. There was no significant difference between Hunter 'a' values for T3 lamb meat and the control, but T3 meat mother-packed in 100:0/CO(2):N(2) had higher 'a' values than those of the control and T3 meat packed in other gas compositions. Lamb steaks in T3 previously mother-packed in 100:0/CO(2):N(2) were also significantly (p<0.05) higher than those of T2 on day 0. T3 meat also maintained initial colour values over those of the control.     

Inoculation of lactic acid bacteria on meat surfaces as a means of decontamination in semitropical conditions

Reduction of microbial populations on carcasses has been achieved and reported by some authors by spraying solutions of organic acids, mainly lactic acid, on the meat surface. However, in practice, lactic acid is very expensive. Production of lactic acid in situ by a controlled lactic fermentation seemed to be a feasible answer. The objective of the present study was to explore the viability of this concept at semitropical conditions, i.e. temperatures around 25°C. In a first experiment, seven starters were tested for their ability to produce lactic acid and reducing the growth rate of pseudomonads, taking these microorganisms as indicators of contamination by spoilage microorganisms. The lactic acid bacteria strains were isolated from native Mexican maize-based beverages, and inoculated on the meat surface. Addition of sucrose and wrapping the samples in PVC film in order to induce a microaerophilic environment encouraged the over-growth of L. bulgaricus and P. pentosaceous over pseudomonads. A second experiment was designed to test a mixture of these two strains and a commercial starter with respect to lactic acid production, overgrowth of lactic acid bacteria over pseudomonads, decolouration and oxidation of the meat samples. It was concluded that a commercial starter (L. plantarum + M. kristinae-varians) resulted in a reduction of pseudomonas growth rate, without notably affecting meat colour and degree of oxidation.     

Beef shelf life in low O(2) and high CO(2) atmospheres containing different low CO concentrations

The use of atmospheres with low concentrations of CO (0.1 to 1%), in combination with O₂ (24%), high CO₂ (50%) and N₂ (25 to 25.9%), for preserving chilled beef steaks was investigated. The atmosphere used as reference contained 70% O₂+20% CO₂+10% N₂. Bacterial counts showed that all atmospheres containing CO greatly reduced total aerobic population numbers, including Brochothrix thermosphacta. Lactic acid bacteria, however, were not affected. CO concentrations of 0.5–0.75% were able to extend shelf life by 5–10 days at 1±1°C, as demonstrated by delayed metmyoglobin formation (less than 40% of total myoglobin after 29 days of storage), stabilisation of red colour (no change of CIE a* and hue angle after 23 days), maintenance of fresh meat odour (no variation of sensory score after 24 days) and significant (P<0.01) slowing of oxidative reactions (TBARS).     

包装方式对牛排贮藏期间微生物数量和演替的影响

为研究包装方式对牛排贮藏期间的品质、微生物数量和演替的影响，牛排分别采用50% O2气调包装（50% O2＋30% CO2＋20% N2）和真空包装在0～4 ℃下贮藏21 d，并检测贮藏期间pH值、肉色、微生物数量和微生物多样性。结果表明：50% O2气调包装组比真空包装具有更好的护色效果；贮藏21 d时，与真空包装组相比，气调包装组菌落总数、乳酸菌数和假单胞菌数降低；两种包装的微生物多样性均随时间延长呈现先升高后降低的趋势，且真空包装牛排比50% O2气调包装牛排具有更复杂的微生物多样性；牛排的初始微生物主要由不动杆菌属、苍白杆菌属、栖热菌属和金黄杆菌属组成，随着贮藏时间的延长，肉食杆菌属逐渐成为真空包装牛排的优势菌群，而环丝菌属、沙雷氏菌属和乳杆菌属则成为50% O2气调包装牛排的优势菌群；贮藏7～14 d是牛排中微生物种类产生变化的关键时间点；相比于真空包装牛排，50% O2气调包装牛排中的微生物群落具有更低的糖代谢和更高的蛋白质代谢能力。本研究结果明确了不同贮藏方法下牛排的品质变化和微生物的演替规律，为定向抑制牛排中的微生物、延长产品货架期提供了参考。     

Improving the flavor of calcium chloride and lactic acid injected mature beef top round steaks

The effect of added commercial beef flavoring on the physical and sensory characteristics of CaCl₂ and lactic acid injected cow meat was investigated. A 10% injection of 0.3 M CaCl₂ and 0.3 M lactic acid into hot-boned top rounds (m. semimembranosus) decreased shear forces over traditional top round steaks. The addition of commercial beef flavoring (4% solution) to the CaCl₂ and lactic acid injection did not alter the resulting pH, cook loss or total aerobic plate count (APC) of injected steaks. However, beef flavoring did increase the beef/brothy and oniony aromatics and salt taste, and decreased the soured and medicinal aromatics and bitter tastes of hot-boned, CaCl₂ and lactic acid injected top round steaks.     

Improvement of shelf-life and wholesomeness of ground beef by irradiation-2. Chemical analysis and sensory evaluation

Lean ground beef was exposed to three dose levels of gamma radiations (Cobalt-60) (1·0, 2·5 and 5·0 kGy). Chemical indices monitored throughout the storage period (16 days, 4°C) included pH, free fatty acids and peroxides. Irradiation clearly contributed to a diminution of the pH and an increase of the peroxides. Free fatty acids were not affected. The 10 non-expert panellists indicated a noticeable effect of irradiation on the odour and colour of the raw product. The odour and flavour of the irradiated cooked ground beef was slightly disliked while no difference was perceived in the colour and texture of the cooked irradiated ground beef. Following these considerations, it is recommended that ground beef be treated with a low dose (such as 1 kGy).     

Combined effects of packaging atmosphere and lactic acid on growth and survival of Listeria monocytogenes in crayfish tail meat 4 degrees C.

The effect of lactic acid on growth and survival of Listeria monocytogenes in crayfish tail meat stored under refrigeration and various gas environments was investigated. Frozen crayfish tail meat was thawed overnight, autoclaved, cooled, and inoculated with approximately 4 log colony-forming units (CFU) of a mixed-strain (Scott A and F5027) L. monocytogenes culture per gram of meat. Inoculated samples were blended with 0, 0.5, 1.0, 1.5, or 2.0% lactic acid and packaged under air, vacuum, or modified atmosphere (74.8% CO2, 10.4% O2, and 14.8% N2) and stored at 4 degrees C for 20 days. Results demonstrated that modified atmosphere packaging inhibited the growth of L. monocytogenes more than air and vacuum packaging at 0 and 1% lactic acid. Microbial counts declined steadily in crayfish tail meat treated with 2% lactic acid, with no differences among the packaging atmospheres. The lag phase was extended by 8 days in samples treated with 1% lactic acid and modified atmosphere compared to that in air or vacuum packaging. Overall, the combination of lactic acid and modified atmosphere had the greatest potential to prevent growth of L. monocytogeines.     

复合保鲜剂对冷鲜肉货架期的影响

采用复合保鲜剂1%醋酸+3%柠檬酸+0.1%抗坏血酸和1%醋酸+1%乳酸+0.2%茶多酚对冷却肉进行处理,分别在0、3、6、9天测定样品的菌落总数、大肠菌群和挥发性盐基氮,并对样品的颜色和感官性状进行评价。结果表明:复合保鲜剂1%醋酸溶液+1%乳酸+0.2%茶多酚可使鲜肉在第6天时,菌落总数、大肠菌群、挥发性盐基氮在鲜肉要求范围之内,并且感官状态良好,该复合试剂能够达到延长冷鲜肉货架期的目的。