基于超微弱发光技术检测辐照食品的研究

基于超微弱发光检测技术,研究即食食品(麦片,藕粉)经0～12kGy剂量辐照后光子信号的变化,并探讨超微弱发光用于鉴定即食辐照食品的判定方法。试验结果表明:两种即食食品辐照前后的超微弱光子计数有明显的区别,光子计数与辐照剂量呈正相关,检测阈值可低至0.3kGy。当添加检测液后的最大光子数为本底的15倍以上时,可判定为该样品经过辐照处理。     

辐照食品分析检测技术的研究进展

本文介绍了国内外辐照食品检测技术的研究进展，着重对化学分析法、电子自旋共振(ESR)法及热释光分析(TL)法进行了阐述，并对今后辐照食品检测技术的研究提出了建议。     

提高辐照食品热释光检测方法效率的技术分析

提出一种提高辐照食品热释光检测效率的改进技术方法,先采用第1发光曲线筛分样品,再利用发光强度比值对筛分后的6 种待定样品进行鉴定。结果表明：改进热释光方法具有100%检测准确率,而需进行参比剂量辐照及后续热释光测量的样品仅为BS EN 1788-2001方法的33.3%,优选筛分阈值后,这一比例还能进一步降低。改进后的辐射食品热释光检测方法明显提高了检测效率,降低了检测费用,是一种可行方法。     

辐照处理肉及其制品的脂肪氧化效应研究

辐照处理肉及肉制品能有效的提高肉品的卫生安全质量、延长保质期。但是，辐照处理会加速肉与肉制品中脂肪的氧化。本文阐述了辐照诱导肉及肉制品脂肪氧化的机理，并对影响脂肪氧化的因素如辐照剂量、环境温度、包装形式以及抗氧化剂筛选及添加量等进行了综述。     

Costs of Food Safety Investments in the Meat and Poultry Slaughter Industries

To develop regulations efficiently, federal agencies need to know the costs of implementing various regulatory alternatives. As the regulatory agency responsible for the safety of meat and poultry products, the U.S. Dept. of Agriculture's Food Safety and Inspection Service is interested in the costs borne by meat and poultry establishments. This study estimated the costs of developing, validating, and reassessing hazard analysis and critical control points (HACCP), sanitary standard operating procedures (SSOP), and sampling plans; food safety training for new employees; antimicrobial equipment and solutions; sanitizing equipment; third‐party audits; and microbial tests. Using results from an in‐person expert consultation, web searches, and contacts with vendors, we estimated capital equipment, labor, materials, and other costs associated with these investments. Results are presented by establishment size (small and large) and species (beef, pork, chicken, and turkey), when applicable. For example, the cost of developing food safety plans, such as HACCP, SSOP, and sampling plans, can range from approximately $6000 to $87000, depending on the type of plan and establishment size. Food safety training costs from approximately $120 to $2500 per employee, depending on the course and type of employee. The costs of third‐party audits range from approximately $13000 to $24000 per audit, and establishments are often subject to multiple audits per year. Knowing the cost of these investments will allow researchers and regulators to better assess the effects of food safety regulations and evaluate cost‐effective alternatives.     

Effect of Antioxidants on Consumer Acceptance of Irradiated Turkey Meat

Antioxidants had no effect on the production of sulfur compounds, color change, and off‐odor intensity of irradiated turkey breast meat, but addition of sesamol + tocopherol or gallate + tocopherol was effective in reducing thiobarbituric acid‐reactive substance values and aldehydes, especially under aerobic conditions. Consumers preferred the color of irradiated raw and cooked meat to nonirradiated meat because the pink color of irradiated meat looked fresher. The packaging method was more important than the antioxidant treatment in reducing irradiation off‐odor because S‐compounds produced by irradiation easily volatilized under aerobic packaging conditions. Therefore, the combined use of aerobic packaging and antioxidants is recommended to improve consumer acceptance of irradiated poultry meat.     

Physicochemical Stability of Fluid Soybean Lecithin Gamma Irradiated for Decontamination Purposes

Soybean lecithin is a food additive mainly used for its emulsifying properties. As many other natural ingredients, it can contain microorganisms capable of causing spoilage to the food products to which it is incorporated that cannot be eliminated by the usual methods due to the damage they can cause to the product. Commercial samples were gamma irradiated at the⁶⁰ Co Facility of the Ezeiza Atomic Center with doses suitable for attaining microbial decontamination (1, 2, 3 and 5 kGy). The technological properties were then evaluated every 2 mo, for a total period of 8 mo (lecithin commercial storage time). Control and irradiated samples were analysed at least by triplicate in viscosity, acid value, acetone insoluble matter (phosphatides), peroxide value, ultraviolet spectra, refraction index, iodine value, thin layer chromatography, test for hydrolysis and emulsifying capacity. The results revealed no significant differences between control and irradiated samples. Gamma irradiation of fluid soybean lecithin can be used for attaining the sanitary specifications while preserving its technological properties.     

A Rapid Direct Solvent Extraction Method for the Extraction of 2-Dodecylcyclobutanone from Irradiated Ground Beef Patties Using Acetonitrile

Abstract: The amount of irradiated beef in the U.S. market is growing, and a reliable, rapid method is needed to detect irradiated beef and quantify the irradiation dose. The official analytical method (BS EN 1785 2003) that has been adopted by the European Union is time consuming. The objective of this study was to develop a rapid method for the analysis of 2-dodecylcyclobutanone (2-DCB) in irradiated beef. A 5 g sample of commercially irradiated ground beef patty (90/10) was extracted with n-hexane using a Soxhlet apparatus or with acetonitrile via direct solvent extraction. The Soxhlet hexane extract was evaporated to dryness, and the sample was dissolved in a mixture of ethyl acetate and acetonitrile (1:1). The defatted extract was purified with a 1 g silica cartridge. Another 5 g aliquot of the same patty was mixed with 50 mL acetonitrile and either blended for 1 min with a hand blender or crushed for 10 min with a glass rod. The extraction procedure was repeated 3 times, and the acetonitrile was collected and evaporated to dryness. Eluants from both methods were concentrated under nitrogen and injected into a gas chromatography-mass spectrometry. The 2-DCB concentration in the commercial samples was 0.031 ± 0.0026 ppm (n = 5) for the Soxhlet method and 0.031 ± 0.0025 ppm (n = 10) for direct solvent extraction. Recovery of 2-DCB from spiked beef samples in the direct solvent extraction method was 93.2 ± 9.0% (n = 7). This study showed that the direct solvent extraction method is simple and as efficient and reproducible as the Soxhlet method.     

Effect of lactic acid treatment during processing on the sensory quality and lactic acid content of fresh broiler chickens

Microbial decontamination by lactic acid treatment during processing of fresh broiler chickens is an effective way to produce a safer product with good keeping quality. It remained to be assessed whether such a treatment adversely affects the organoleptic quality of the product. Lactic acid treatment results in an increased acid concentration in the skin, with no increase in lactic acid concentration in the underlying muscle tissue. Differences in sensory quality were only found in appearance of the carcasses, the controls being identified as discoloured. A preference test did not show any difference in lactic acid treated and untreated grilled legs.     

辐照技术对食品及包装材料迁移规律的影响

随着食品辐照技术的迅速发展,辐照食品的安全性也逐渐受到广大消费者的重视。辐照技术可以杀死食物中的致病微生物及部分的腐败细菌,抑制食物劣变的生理和生化过程,使食物不易腐败,起到保持食物新鲜的作用。辐照技术的优势很多,但是辐照技术对包装材料的物理化学变化也不容忽视,食品包装中大多数的食品是与包装材料直接接触,辐照对包装材料的影响也会直接影响到食品的安全。目前国内外对60Co-γ辐照技术和电子束辐照技术的应用最为广泛,文章将分别论述2种辐照技术的特点及研究、应用现状,旨在为今后辐照技术的安全发展提供参考。     

食品检验对肉制品安全重要性分析

食品检验是发现和改善肉制品安全问题的重要保证。本文分析了肉制品检验中存在的问题,简述了几种常用的肉制品检验方法,以及目前在肉制品检验中应用的新技术,同时提出了检验中可改进的地方,展望了我国的肉制品检验技术前景。通过分析食品检验的重要性能够更好的保障我国肉制品的安全,促使肉制品行业朝着健康可持续的方向发展,使百姓吃到放心肉制品。     

基于DNA条形码技术常见肉类掺假鉴别技术的研究

根据市场上常见的肉类掺假情况,本研究通过提取生鲜牛肉、羊肉、猪肉和鸭肉基因组DNA,按一定比例进行预混合,构建牛肉掺猪肉、羊肉掺猪肉、牛肉掺鸭肉和羊肉掺鸭肉4种掺假模型。通过引物COI-1和COI-2进行PCR扩增和测序比对,建立基于COI基因的动物源性食品的掺假判别方法。根据实验所得纯肉DNA提取率T实现DNA水平到肉水平掺假比例的换算。在肉的掺假水平上,引物COI-2检测效果较好,对牛-猪、羊-猪、牛-鸭和羊-鸭模型掺假物的检出限分别为5%、8%、1%和4%。对采集的28个批次的肉制品进行检测,结果表明:28个样品中89%的样品与产品标签标识的成分相符。建立的基于DNA条形码技术的检测方法可作为一种简单、快速、有效的分子鉴定技术,可以直接应用于研究物源性食品的种类和掺假鉴定。     

辐照食品检测标准及检测方法研究进展

介绍国内外辐照食品的检测标准和检测技术的原理、优缺点及研究进展,并对今后我国辐照食品检测技术的研究和发展进行了展望.     

基于分数阶微积分的食品质量防伪检测方法研究

本文以江中猴姑早餐米稀、乐事薯片、港荣奶香蒸蛋糕、豪士乳酸菌酸奶小口袋面包作为食品样品研究对象,并选取相对应造假样品,通过分数阶微积分方法对食品质量进行防伪检测。在市场上获取真伪样品各90个,采用分数阶微积分获取食品能量信号的分数阶微分算子及函数分数阶导数,加强食品二维码原图灰度值改变较大的高频边缘信息,同时保持其灰度直方图分布包络,保证了食品二维码图像纹理细节信息的基本完整性,以实现分析不同食品真伪二维码分数阶微积分的差异。经实验结果发现,采用分数阶微积分方法在初始分类检测时,总初始准确检测率高达95.56%;在交叉验证中,总检测准确率为88.89%,能够为食品质量防伪检测提供技术支持,为维护食品质量的市场秩序奠定理论基础。     

肉类食品清洗解冻装置的研究进展

解冻与清洗一直是肉类食品加工工艺中非常重要的环节,解冻的好坏直接影响肉类的品质,而清洗的干净与否直接影响食品卫生指标。介绍了近年来清洗装置与解冻装置的研究现状和进展,针对清洗装置结构单一,浪费水源,清洗效果不佳,解冻装置设备复杂,解冻时间长或解冻质量差等问题进行了深入研究。     

Radiation Sensitivity of Listeria monocytogenes on Beef as Affected by Temperature

Longissimus dorsi from beef was inoculated with Listeria monocytogenes and the effect of gamma irradiation on the survival of this pathogen at ?60 to +15°C was determined. Radiation D-values were determined for inactivation of L. monocytogenes at 5°C intervals from ?20 to 5°C. These data were used to develop an equation to predict the response to gamma radiation within that range. An abrupt increase in resistance occurred at ?5°C. The radiation D-value was 0.45 kGy at 0°C, 0.77 kGy at ?5°C and 1.21 kGy at ?20°C. A straight line was obtained when the log₁₀ of the D-values from ?5 to ?20°C was plotted vs the reciprocal of the absolute temperature. This led us to calculate a value analogous to the Arrhenius activation energy for inactivation of L. monocytogenes by gamma radiation.     

7 种食品防腐剂对肉制品污染微生物的 抑菌效果比较研究

通过测定抑菌率和最低抑菌质量浓度,研究化学防腐剂山梨酸钾、双乙酸钠、单辛酸甘油酯、乙二胺四乙酸二钠(EDTA)以及生物防腐剂乳酸链球菌素(Nisin)、壳聚糖、ε-聚赖氨酸(ε-PL)对12株肉制品腐败(包括2株环状芽孢杆菌(Bacillus circulans)、3株枯草芽孢杆菌(Bacillus subtilis)、3株地衣芽孢杆菌(Bacillus licheniformis)、2株凝结芽孢杆菌(Bacillus coagulans)、1株蜂房哈夫尼亚菌(Hafnia alvei)以及1株肠球菌(Enterococcus))的抑菌活性。结果表明：7种防腐剂对供试菌都有一定的抑菌效果,抑菌效果强弱顺序为：Nisin＞壳聚糖＞ε-PL＞单辛酸甘油酯＞EDTA＞双乙酸钠＞山梨酸钾。3种生物防腐剂的抑菌效果明显强于其他4种化学防腐剂。通过比较各种防腐剂对不同种和同种不同株的细菌的抑菌效果,表明同一种防腐剂不仅对不同种的细菌抑菌效果不同,即使对同种不同株的细菌其抑菌效果也有很大差异。     

Development of a New Paenibacillin‐Producing Strain and Testing its Usability in Improving Food Safety

A new bacterial strain that produces a bacteriocin (paenibacillin) without polymyxin was developed from Paenibacillus polymyxa that co‐produces the 2 antimicrobial agents. Gamma radiation was used successfully to develop the new strain, P. polymyxa OSY‐HG. Subsequently, we explored the feasibility of using food or food ingredients as growth media for the new strain. Milk supported the growth of P. polymyxa OSY‐HG which produced up to 32 mg paenibacillin/L milk without polymyxin. Fermentation crude extract was applied in a model food (Vienna sausage) to control Listeria innocua, a Listeria monocytogenes surrogate. The treatment increased Listeria lag time by 2 d at 7 °C and at least 6 h at 37 °C. In conclusion, a new paenibacillin‐producing P. polymyxa strain has been developed for potential industrial use. Using the new strain in applications that enhance food safety is feasible.     

Fluorimetry via a quartz-glass rod for predicting the skin content and processing characteristics of poultry meat slurry

Collagen fluorescence in comminuted mixtures of chicken skin and muscle was measured through a quartz-glass rod. High proportions of skin decreased the gel strength of the cooked product (r=—0.99, P < 0.005), caused higher cooking losses (r = 0.99, P < 0.005) and decreased the fluid-holding capacity measured by centri-fugation (r=—0.92, P < 0.005). Fluorescence intensity was strongly correlated with skin content (r<0.99 from 460 to 510 nm) and, thus, was strongly correlated with gel strength, cooking losses and fluid-holding capacity.