Maintenance of safety and quality of refrigerated ready-to-cook seasoned ground beef product (meatball) by combining gamma irradiation with modified atmosphere packaging

Abstract: Meatballs were prepared by mixing ground beef and spices and inoculated with E. coli O157:H7, L. monocytogenes, and S. enteritidis before packaged in modified atmosphere (3% O₂+ 50% CO₂+ 47% N₂) or aerobic conditions. The packaged samples were irradiated at 0.75, 1.5, and 3 kGy doses and stored at 4 °C for 21 d. Survival of the pathogens, total plate count, lipid oxidation, color change, and sensory quality were analyzed during storage. Irradiation at 3 kGy inactivated all the inoculated (approximately 10⁶ CFU/g) S. enteritidis and L. monocytogenes cells in the samples. The inoculated (approximately 10⁶ CFU/g) E. coli O157:H7 cells were totally inactivated by 1.5 kGy irradiation. D¹⁰‐values for E. coli O157:H7, S. enteritidis, and L. monocytogenes were 0.24, 0.43, and 0.41 kGy in MAP and 0.22, 0.39, and 0.39 kGy in aerobic packages, respectively. Irradiation at 1.5 and 3 kGy resulted in 0.13 and 0.36 mg MDA/kg increase in 2‐thiobarbituric acid‐reactive substances (TBARS) reaching 1.02 and 1.49 MDA/kg, respectively, on day 1. Irradiation also caused significant loss of color and sensory quality in aerobic packages. However, MAP effectively inhibited the irradiation‐induced quality degradations during 21‐d storage. Thus, combining irradiation (3 kGy) and MAP (3% O₂+ 50% CO₂+ 47% N₂) controlled the safety risk due to the potential pathogens and maintained qualities of meatballs during 21‐d refrigerated storage. Practical Application: Combined use of gamma irradiation and modified atmosphere packaging (MAP) can maintain quality and safety of seasoned ground beef (meatball). Seasoned ground beef can be irradiated at 3 kGy and packaged in MAP with 3% O₂+ 50% CO₂+ 47% N₂ gas mixture in a high barrier packaging materials. These treatments can significantly decrease risk due to potential pathogens including E. coli O157:H7, L. monocytogenes, and S. enteritidis in the product. The MAP would reduce the undesirable effects of irradiation on quality, and extend the shelf life of the product for up to 21 d at 3 °C.     

Hydrogen uptake in austenitic stainless steels by exposure to gaseous hydrogen and its effect on tensile deformation

Hydrogen solubility and diffusivity of Fe–Cr–Ni austenitic stainless steels were measured through exposure to gaseous hydrogen at a pressure of 10 MPa over the temperature range 110–235 °C. The hydrogen solubility depended on the alloy compositions, whereas the diffusion coefficients were nearly identical at a given temperature. Hydrogen uptake in the stable austenitic steels by exposure to high-pressure gaseous hydrogen led to some loss of ductility, while their fracture surfaces showed evidence of plastic deformation. This was attributed to the enhanced inhomogeneity of plastic deformation in the presence of hydrogen and the increased stress for plastic instability with increasing hydrogen concentration.     

The analysis of leakage current in MIS Au/SiO2/n-GaAs at room temperature

The aim of this study is to determine the reverse-bias leakage current conduction mechanisms in Au/SiO₂/n-GaAs metal-insulator-semiconductor type Schottky contacts. Reverse-bias current-voltage measurements (I–V) were performed at room temperature. The using of leakage current values in SiO₂ at electric fields of 1.46–3.53 MV/cm, ln(J/E) vs. $\sqrt E $ graph showed good linearity. Rom this plot, dielectric constant of SiO₂ was calculated as 3.7 and this value is perfect agreement with 3.9 which is value of SiO₂ dielectric constant. This indicates, Poole-Frenkel type emission mechanism is dominant in this field region. On the other hand, electric fields between 0.06–0.73 and 0.79–1.45 MV/cm, dominant leakage current mechanisms were found as ohmic type conduction and space charge limited conduction, respectively.     

Surface roughness properties of polyester woven fabrics after abrasion

Effect of abrasion on surface roughness properties of textured polyester woven fabrics has been investigated. The effects of weft density, weft yarn filament number, fiber fineness, and weave pattern on surface roughness after abrasion were studied. Surface roughness values of control fabric (not abraded) and abraded fabrics after four different abrasion cycles were discussed according to different constructional parameters. Surface roughness values of fabrics changed according to abrasion cycles and the changes were related to yarn float lengths, yarn densities, yarn fiber fineness, and initial fabric surface roughness. A general overview of the results showed that abrasion eliminated the effect of texture especially at the fabric samples with initially high surface roughness. The surface roughness of fabrics with initially high surface roughness decreased at a greater extent than the ones with low surface roughness after abrasion. Fabrics with high surface roughness were affected more by abrasion and the effect of abrasion on rough surfaces depended on different manners regarding the compactness of woven structures.     

Surface roughness properties of wool woven fabrics after abrasion

Effects of abrasion on surface roughness properties together with appearance of woven wool fabrics have been investigated. The effects of weft yarn count, weft yarn density, and weave pattern on fabric surface roughness after abrasion were researched. Surface roughness values of control fabric (not abraded) and abraded fabrics after four different abrasion cycles were discussed according to different fabric constructional parameters. It was observed that the greatest decreases in surface roughness values after abrasion were observed in loose fabric structures which had the highest initial fabric surface roughness values (coarse yarn, low yarn density, and low yarn intersection). The results showed that change of roughness properties of wool fabric surfaces after abrasion depends on the initial surface roughness values and on the amount of contact area of fabrics based on the fabric constructional parameters.     

气动乳化液自动配比仪的设计

提出了气动乳化液自动配比仪的构想,该配比仪以井下压风为动力,利用综合控制器(PLC)作为控制单元,实现乳化液浓度的自动配比。其配液方式可分为自动调节和人工调节两种。该装置不仅能够更好地实现乳化液的全封闭式管理,保持乳化液系统的清洁,降低液压支架液压元件的损坏,也大大减少了乳化油的浪费。     

矿井供用电综合监测调控一体化的实现

详细介绍了一套新型矿井供用电综合监控系统,它运用了先进的网络通讯技术、现场总线技术、DSP 技术和先进供用电参数采集设备,全面系统地对所有用电设备进行远程集中监测和调控,从而真正实现系统的管、控一体化,可方便地对系统进行效率测试分析,实现运行过程中的自动跟踪与提高效率的控制调节。     

浅谈锚网索支护方式及支护效果分折

从以下几点介绍了锚网索支护施工方式,并做了效果分析:(1)锚杆直径与钻孔直径的合理匹配;(2)选择合理的树脂药卷直径;(3)提高锚索二次耦合支护效果;(4)锚杆、锚索二次补强的时间和强度.     

Double subband occupation of the two-dimensional electron gas in InxAl1 − xN/AlN/GaN/AlN heterostructures with a low indium content (0.064 ≤ x ≤ 0.140) barrier

We present a carrier transport study on low indium content (0.064 ≤ x ≤ 0.140) In_xAl_1 − xN/AlN/GaN/AlN heterostructures. Experimental Hall data were carried out as a function of temperature (33-300 K) and a magnetic field (0-1.4 T). A two-dimensional electron gas (2DEG) with single or double subbands and a two-dimensional hole gas were extracted after implementing quantitative mobility spectrum analysis on the magnetic field dependent Hall data. The mobility of the lowest subband of 2DEG was found to be lower than the mobility of the second subband. This behavior is explained by way of interface related scattering mechanisms, and the results are supported with a one-dimensional self-consistent solution of non-linear Schrödinger-Poisson equations.     

DCQH-9718多功能储能式桥丝自动焊接机及其应用

文章介绍一种适合于我国工业电雷管弹性引火元件桥丝自动焊接设备的工作原理,特点及其在生产中的应用,它的应用简化了工业电雷管引火元件制造工艺,改变了雷管桥丝焊接方式,对推动我国工业电雷管生产自动化进程具有一定的意义。