Synergic antimicrobial activity of lysozyme, nisin, and EDTA against Listeria monocytogenes in ostrich meat patties

Synergic antimicrobial activity of lysozyme (250 ppm), nisin (250 ppm), and disodium ethylenediamine tetraacetic acid (EDTA) (20 mM) against Listeria monocytogenes and meat-borne spoilage bacteria in ostrich patties packaged in air and vacuum was studied. The antimicrobial treatment decreased the L. monocytogenes population in ostrich patties below the official limit of the European Union (<2 log CFU/g). The total viable counts for the treated samples (air and vacuum) showed a reduction of 1 log cycle until to 2 d of storage; after this period the cell load increased. Moreover, the reduction of 2 log cycle for the lactic acid bacteria was observed. Enterobacteriaceae and Pseudomonas spp. were not affected by the antimicrobial treatment in both packaging atmospheres. Sensory evaluation did not differ between treated and untreated samples as regard to the color. The ostrich patties packaged in vacuum had a desirable odor during the storage time and were not affected by antimicrobial treatment. The off-odors for the patties packaged in air developed faster in the control while the odor scores for the treated samples remained above the rejection point up to the end of storage. PRACTICAL APPLICATION: Great interest is developing in food bio-preservation, because of the ever-increasing needs to protect consumers' health and to valorize the naturalness and safety of food products.     

Nisin、溶菌酶用于斑点叉尾鮰鱼片保鲜的研究

以Nisin(乳链菌肽)、溶菌酶及VC(抗坏血酸)为保鲜剂,用于斑点叉尾鮰鱼片的冷藏保鲜,采用正交试验对复合保鲜剂的配比进行优选,并以细菌总数、TVB-N 值、pH 值及感官评分为鲜度指标,测定复合保鲜剂的保鲜效果。结果表明：复合保鲜剂最优配比为0.5% Nisin+0.3% 溶菌酶+3.0% VC,并用乳酸调节pH4.5,用此保鲜剂处理再结合真空包装能使斑点叉尾鮰鱼片在0℃条件下保鲜21d。     

Reduction of Brochothrix thermosphacta and Salmonella Serotype Typhimurium on Vacuum-Packaged Fresh Beef Treated with Nisin and Nisin Combined with EDTA

ABSTRACT: The effect of nisin and nisin/EDTA followed by vacuum packaging on the reduction of Brochothrix thermosphacta and Salmonella typhimurium counts on beef was investigated. Beef cubes, inoculated with either bacteria, were dipped in nisin, or nisin combined with EDTA solutions, vacuum packaged, and stored at 4 °C for up to 25 d. Growth of B. thermosphacta was completely inhibited by nisin and nisin/EDTA by up to 6.76 log₁₀ CFU/ml. However, neither treatment showed significant effects against S. Typhimurium. Thus, nisin or nisin/EDTA treatment, followed by vacuum packaging under refrigerated conditions could increase the shelf life of fresh beef by inhibiting the growth of B. thermosphacta , an important spoilage organism in beef.     

Use of nisin, lysozyme and EDTA for inhibiting microbial growth in chilled buffalo meat

The effect of nisin, lysozyme and lysozyme combined with disodium ethylenediaminetetraacetate salt (EDTA) for inhibiting the growth of spoilage micro‐organisms in buffalo meat was investigated. Prior to packaging, the samples were alternatively dipped in solutions containing different concentrations of nisin, lysozyme and combinations of a pre‐fixed amount of lysozyme and different concentrations of EDTA. The packed meat samples were stored at 4 °C, and the microbial changes were monitored for a period of 8 days. The best results, in terms of microbial shelf‐life extension, were obtained by dipping the meat steaks in a solution containing a combination of 0.5% of lysozyme and 2% of EDTA. This treatment was able to reduce the growth of all the investigated bacteria and showed a bactericidal effect on Brochotrix thermosphacta during the entire period of storage.     

Fat Content Effects on Yield, Quality, and Microbiological Characteristics of Chicken Patties

Mixtures of ground chicken thigh meat and fat were formulated to contain 5, 10, 15, and 20% fat. Hunter color values, drip and cooking losses, proximate composition, texture profiles, and rates of microbial spoilage were compared for patties prepared from the mixtures. Raw patties became lighter and more yellow as fat content increased but cooking obscured these trends. As fat content increased, cooking losses and moisture:protein ratios increased. Lower fat patties were harder, springier, less cohesive and chewier than patties containing higher fat levels. Rates of bacterial spoilage were unaffected by fat content.     

复合添加剂提高调理肉饼乳化性的工艺优化

为提高调理肉饼的乳化性（保水性和保油性）,以卡拉胶、大豆分离蛋白、黄原胶和复合磷酸盐为添加剂,分别以水分流失率和脂肪流失率为指标,考察4 种添加剂对调理肉饼乳化性能的影响,并通过正交试验优化4 种添加剂的最佳配比。结果表明：单一添加组分能够改善调理肉饼的保水保油性;与单一添加相比,复合添加进一步提高了调理肉饼的乳化能力,其中以0.6%卡拉胶、4%大豆分离蛋白、0.6%黄原胶和0.5%复合磷酸盐组合的乳化性能较强,水分流失率和脂肪流失率分别为15.26%和11.17%。上述研究结果表明,将复合添加剂应用于调理肉饼加工中能提高其保水保油性,增强乳化性能。     

Precooked Reduced-Fat Beef Patties Chemical and Sensory Quality as Affected by Sodium Ascorbate, Lactate and Phosphate

Beef-carrageenan (BC; 10% fat) patties—with sodium ascorbate (0.05%), sodium lactate (3%), sodium tripolyphosphate (0.3%), ascorbate-phos-phate, ascorbate-lactate, or none—and 20%-fat all-beef patties were cooked, aerobically or vacuum packaged, and stored at 4°C or ?20°C. Fat level had a greater effect on texture than did additives. Lactate and phosphate increased cooking yield of BC patties. Phosphate was antioxidative but not antimicrobial. Ascorbate was antioxidative and reduced aerobic plate counts (APCs) of aerobically packaged refrigerated BC. Lactate reduced APCs of both aerobically and vacuum packaged BC patties. Lactate had a prooxidative effect in aerobically-packaged/frozen patties but showed no such effect in vacuum-packaged/frozen patties or refrigerated patties. Ascorbate-phosphate was most effective in minimizing flavor deterioration in refrigerated BC patties.     

蔬菜浆对调理猪肉饼品质特性的影响

为研究蔬菜浆对调理猪肉饼品质特性的影响,将芹菜浆、胡萝卜浆及二者的复合浆分别添加到猪肉饼中,4 ℃冷藏,观察猪肉饼理化性质及成品感官品质的变化。结果表明：与对照组相比,添加蔬菜浆的各处理组猪肉饼pH值、硫代巴比妥酸反应物值均降低,冷藏5 d时降低最明显,胡萝卜浆组pH值下降较快,且冷藏5 d时pH值显著低于芹菜浆组（P＜0.05）;添加芹菜浆能够显著降低猪肉饼的亮度值,显著增加红度值（a*）（P＜0.05）,且芹菜浆组a*高于胡萝卜浆组;添加蔬菜浆也可提高猪肉饼的出品率;利用5 点快感标度法对各处理组猪肉饼进行感官评价,猪肉饼的色泽、香气、口感、质地及总体可接受程度评分与对照组相比均有所提高,芹菜浆对猪肉饼的色泽、香气和口感等指标的改善效果优于胡萝卜浆。     

Addition of Antioxidant to Improve Quality and Sensory Characteristics of Irradiated Pork Patties

The effects of added antioxidants on the oxidative quality changes of irradiated pork patties were studied. Lipid oxidation (TBARS) was not a concern, even in aerobically packaged irradiated pork patties when antioxidants were added. Irradiation produced sulfur compounds, such as dimethyl sulfide and dimethyl disulfide, responsible for irradiation off‐odor. The addition of gallate + tocopherol or sesamol + tocopherol was effective in reducing the sulfur volatiles, but had no effect on the redness of irradiated raw pork patties. Aerobic packaging was highly effective in reducing sulfur volatiles and off‐odor from irradiated meat during storage. Antioxidants had little effect on the sensory characteristics and consumer acceptance of irradiated pork, and consumers did not consider the red color of irradiated raw pork as a quality defect.     

Active packaging of ground beef patties by edible zein films incorporated with partially purified lysozyme and Na2EDTA

In this study, antimicrobial activity of zein films incorporated with partially purified lysozyme and disodium ethylenediaminetetraacetic acid (Na₂EDTA) has been tested on selected pathogenic bacteria and refrigerated ground beef patties. The developed films containing 700 μg cm^?2 lysozyme and 300 μg cm^?2 Na₂EDTA showed antimicrobial activity on Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella typhimurium. The application of lysozyme and Na₂EDTA incorporated zein films on beef patties significantly decreased total viable counts (TVC) and total coliform counts after 5 days of storage compared to those of control patties (P < 0.05). Zein films incorporated with lysozyme and Na₂EDTA or Na₂EDTA alone significantly slowed down the oxidative changes in patties during storage (P < 0.05). Redness indices of patties coated with zein films were significantly lower than those of uncoated control patties during storage (P < 0.05). This study demonstrated the potential usage of zein films containing lysozyme and Na₂EDTA for active packaging of refrigerated meat products.     

Modeling Microbial Spoilage and Quality of Gilthead Seabream Fillets: Combined Effect of Osmotic Pretreatment,Modified Atmosphere Packaging,and Nisin on Shelf Life

ABSTRACT: The objective of the study was the kinetic modeling of the effect of storage temperature on the quality and shelf life of chilled fish, modified atmosphere-packed (MAP), and osmotically pretreated with the addition of nisin as antimicrobial agent. Fresh gilthead seabream (Sparus aurata) fillets were osmotically treated with 50% high dextrose equivalent maltodextrin (DE 47) plus 5% NaCl. Water loss, solid gain, salt content, and water activity were monitored throughout treatment and treatment conditions were selected for the shelf life study. Untreated and osmotically pretreated slices with and without nisin (2 × 10⁴ IU/100 g osmotic solution), packed in air or modified atmosphere (50% CO₂–50% air), and stored at controlled isothermal conditions (0, 5, 10, and 15 °C) were studied. Quality assessment and modeling were based on growth of several microbial indices, total volatile nitrogen, trimethylamine nitrogen, lipid oxidation (TBARS), and sensory scoring. Temperature dependence of quality loss rates was modeled by the Arrhenius equation, validated under dynamic conditions. Pretreated samples showed improved quality stability during subsequent refrigerated storage, in terms of microbial growth, chemical changes, and organoleptic degradation. Osmotic pretreatment with the addition of nisin in combination with MAP was the most effective treatment resulting in significant shelf life extension of gilthead seabream fillets (48 days compared to 10 days for the control at 0 °C).     

Histological,Biophysical, Physical and Chemical Characteristics of Different Ostrich Muscles

Some characteristics generally related to meat quality were evaluated in several muscles from the leg of the ostrich. Ostrich meat is characterised by a relatively high pH_f and low intramuscular fat content. Although standard slaughtering procedures of ostriches at present comprise the removal of legs within 30 min post mortem from the carcass, relatively long sarcomere lengths and the absence of a linear relationship ( P> 0·05) between sarcomere length and Warner–Bratzler shear measurements (WBS) show that no cold shortening occurs in the different muscles. The means obtained for the Iliotibialis lateralis are representative of the mean of all the individual muscles combined regarding the characteristics muscle fibre diameter, WBS and pigment content. The overall mean for sarcomere length, pH_f and collagen content of all the individual muscles combined can be deduced from determination of these characteristics in the Femorotibialis medius .     

Effects of Rosemary Extract and Sodium Lactate on Quality of Vacuum-packaged Ground Ostrich Meat

ABSTRACT Vacuum‐packaged ground ostrich meat patties containing 2% sodium lactate (SL), 0.2% rosemary extract as oleoresin (RE), or their mixture (MIX) were evaluated and compared with control for their storage stability at 3 ± 1 °C in the dark by measuring pH, 2‐thiobarbituric acid‐reactive substance (TBARS) values, sample color (CIE L*, a*, b*, Hue and Chroma), and microbiological content. The pH values of ostrich patties, ranging from 6.03 to 6.13, were not affected by treatment (P < 0.05). At 9 d of storage, TBARS concentration for control samples containing no additives was 1.64 mg malonaldehyde/kg meat. Addition of RE to the ground ostrich meat inhibited lipid oxidation during storage at 3 ± 1 °C (P < 0.05). TBARS values of SL‐added samples were lower than control samples (P < 0.05); addition of SL also delayed the oxidation. It was found that RE had a protective effect on color, whereas addition of SL decreased CIE a* values (P < 0.05). SL, either alone or with RE, was effective in inhibiting total aerobic bacteria (TAB), coliforms, lactic acid bacteria (LAB), and Brochothrix thermosphacta in ostrich patties (P < 0.05) and provided a 2‐log reduction in microbial population during storage. In addition, RE did not have a significant effect on microbial growth at the concentration used in this study.     

鸵鸟毛漂白增白及染色工艺的研究

以陕西英考鸵鸟股份有限公司养殖的鸵鸟羽毛作为原材料,在了解鸵鸟羽毛组织构造的基础上,对鸵鸟羽毛漂白增白及染色工艺过程中应该注意的几个主要工序,如脱脂、媒介、退色漂白、增白、染色等,以及如何减少羽毛损伤,保持鸵鸟羽毛柔软丰满以及其它独特性能等问题进行了研究,制作出了柔软、丰满、飘逸、鲜艳的鸵鸟羽毛加工品。     

温度、超声、nisin协同脉冲磁场杀灭枯草芽孢杆菌的研究

本文对温度（50~100 ℃）、超声（200 W,5~30 min）、nisin（100~350 IU/mL）协同磁场强度为3.0 T,脉冲数为30个的脉冲磁场杀灭枯草芽孢杆菌进行了研究。结果表明：先脉冲磁场处理后温度处理时,温度越高,杀菌效果越好,当温度为100 ℃,枯草芽孢杆菌的残留率最低为3.17%;先脉冲磁场处理再采用超声功率800 W,工作5 s间隙10 s的超声处理后,超声总时间越长杀菌效果越好,当超声时间为30 min时,枯草芽孢杆菌的残留率最低为8.18%;先脉冲磁场处理后nisin处理时,浓度越高杀菌效果越好,当nisin终浓度为350 IU/mL时,枯草芽孢杆菌的残留率最低为19.21%;先脉冲磁场处理再温度、超声、nisin处理的杀菌效果比先温度、超声、nisin处理后再脉冲磁场处理的杀菌效果要好,这与扫描电镜的观察结果相吻合。协同杀菌后,枯草芽孢杆菌的形态发生改变,细胞产生萎缩现象,脉冲磁场处理后再用nisin协同处理,枯草芽孢杆菌的内容物出现泄漏。     

Physical, Chemical, and Sensory Properties of Bologna Sausage Made with Ostrich Meat

Three formulations of bologna were prepared, differing only by the lean meat used: (1) ostrich meat from Iliofibularis muscle (fan thigh), (2) ostrich meat from Femorotibialis medius muscle (tip thigh), and (3) beef meat from Subscapularis muscle (shoulder). Physical, chemical, and sensory analyses were made. The final products formulated with ostrich meat, although having a dark appearance, were acceptable in chemical composition and other sensory characteristics. The low fat and high protein content for ostrich bolognas will help to ensure that, if marketed in sufficient quantities, ostrich meat can successfully compete with other healthy meat products. The ostrich meat (Iliofibularis muscle) formula reached the highest general quality scores in the sensory evaluation.     

异Vc钠、红曲色素及Nisin替代部分亚硝酸钠对腊肠品质的影响

本文主要研究异Vc钠、红曲色素及Nisin代替部分亚硝酸钠在腊肠中的应用,以酸价、红度、挥发性盐基氮、亚硝酸盐残留量和感官评价作为评价指标,通过单因素试验及正交试验,确定了添加原料肉重的0.065%异Vc钠,0.15%红曲色素、0.06%Nisin及40 mg/kg亚硝酸钠制作的腊肠,与添加90 mg/kg亚硝酸钠制作的腊肠品质接近。     

石榴皮提取物对生猪肉饼品质的影响

研究石榴皮提取物的抗氧化性能及不同质量分数（0.01%、0.05%和0.10%）石榴皮提取物的添加对生猪肉 饼pH值、蒸煮损失、色差和冷藏过程中脂肪及蛋白氧化的影响。结果表明：石榴皮提取物富含多酚和黄酮,其总 抗氧化能力、自由基清除能力、Fe2＋螯合能力随石榴皮提取物质量分数增大而增强;石榴皮提取物的添加对生猪肉饼的 pH值和蒸煮损失率无显著影响,但对生猪肉饼的亮度值、红度值有一定的负面作用;石榴皮提取物能有效抑制生猪肉 饼冷藏过程中氢过氧化物、丙二醛及蛋白羰基生成,且质量分数越高抑制效果越好,整体效果优于丁基羟基茴香醚。     

浅谈鸵鸟皮的结构、初加工和鞣制工艺

鸵鸟皮具有独特的天然毛孔，是可开发的新皮源种。本文在分析鸵鸟原皮基本结构的基础上，对鸵鸟皮的剥取和初步加工，以及制革工艺进行了研究。     

辅料配比及烹饪方式对速冻羊肉饼品质的影响

研究木薯磷酸酯淀粉、土豆浆和明胶3 种辅料对速冻羊肉饼质构特性与感官品质的影响,确定羊肉饼的最 佳工艺配方;同时对3 种烹饪方式（100 ℃蒸煮20 min、121 ℃高温蒸煮20 min、160 ℃大豆油油炸8 min）熟制后 的羊肉饼进行质构、风味特性及感官品质评价。结果表明：当木薯磷酸酯淀粉、土豆浆和明胶添加量分别为12%、 90%和1.5%时,羊肉饼的质构特性和感官评分的综合评价最好;油炸羊肉饼的硬度、弹性和咀嚼性明显优于其他 2 种烹饪方式（P＜0.05）,且油炸羊肉饼中的醛类、含氮含硫类物质等羊肉特殊挥发性风味物质的种类及相对含 量均显著高于其他2 种烹饪方式（P＜0.05）。综上所述,辅料配方中木薯磷酸酯淀粉、土豆浆和明胶添加量分别 为12%、90%和1.5%、经160 ℃大豆油炸熟制的羊肉饼咀嚼性更强、风味佳、品质好。