Quality Changes and Safety Evaluation of Ready-to-Eat Roasted Antarctic Krill(Euphausia superba)During Storage at Room Temperature(25℃)

The objective of this study was to determine the quality changes and shelf life of ready-to-eat roasted Antarctic krill,either untreated(CT)or treated with sodium diacetate(SD)or sodium diacetate and a deoxidizer(SDD),during storage at room temperature(25℃)by using sensory,physiochemical,and microbial assessment.Additionally,fluoride accumulation in this food product was used to evaluate its safety.Analysis showed that the addition of SD and SDD resulted in better sensory scores compared of that of CT samples(P<0.05).Accordingly,microorganism growth and total basic nitrogen(TVB-N)were maintained at a low level for the duration of storage with SD and SDD treatments.The total viable counts of SD and SDD reached(4.58±0.08)log(CFU g^(−1))and(4.20±0.11)log(CFUg^(−1)),respectively.The mold was found after 6 and 18 days for SD and SDD treatment,and the numbers reached 5.2×10^(6) and 8.5×10^(4) respectively at the end of shelf life.The TVB-N values from CT continuously increased during the whole storage.While TVB-N values from SD and SDD remained significantly less change(P<0.05)during the early 20 days of the storage,and the values reached(12.11±0.07)mg(100 g)^(−1) and(10.88±0.15)mg(100 g)^(−1) on day 33 and day 70,respectively.Importantly,SDD treatment effectively minimized the oxidation values and retained the color of ready-to-eat roasted Antarctic krill.Our results showed that the shelf life of ready-to-eat roasted Antarctic krill treated with SDD was extended by up to 52 days.Additionally,rats fed ready-to-eat roasted Antarctic krill showed accumulation of fluoride exclusively in the thighbone.The accumulation of fluoride residues in the thighbone showed concentration-dependent.The concentrations of fluoride residues in rats were(1760.03±38.21),(2371.52±42.15)mgkg^(−1) and(3615.44±30.53)mgkg^(−1),which were less than sodium fluoride feeding group(4621.01±28.67)mgkg^(−1).The results suggested that the SD and SDD treatments led to better quality and shelf life extension of ready-to-eat roasted Antarctic krill during storage at room temperature(25℃).Therefore,the ready-to-eat roasted Antarctic krill can be of great interest to the seafood industry.

香榧油复合EGCG纳米乳液制备及其对沙拉酱和月饼的品质影响

利用超声处理制备香榧油(Torreya oil)与表没食子儿茶素没食子酸酯(Epigallocatechin gallate,EGCG)复合纳米乳液,分析不同油水比、EGCG添加量在不同储存温度和时间下的乳液稳定性,并进一步研究添加该纳米乳液对沙拉酱和月饼的品质影响。结果表明,制备的香榧油复合EGCG纳米乳液性质稳定(粒径分布在160~180 nm、多分散性指数小于0.2、Zeta电位接近﹣60 mV),油水比和EGCG对纳米乳液稳定性影响不显著;冷藏、复合2.0%EGCG的纳米乳液有利于减少EGCG的损失从而抑制其褐变;添加1/10香榧油复合EGCG纳米乳液、0.2%新甲基橙皮苷二氢(New methyl hesperi dindihydrogen,NHDC)的沙拉酱感官风味提升,显著增强抑菌和抗氧化活性,提高其品质稳定性;添加香榧油复合EGCG乳液能够减缓月饼烘制中的丙烯酰胺累积、减少代表性不饱和脂肪酸的损失。以上结果表明,EGCG纳米乳液在提升食品品质方面有着重要意义和开发利用前景。

即食沙拉各组分中单增李斯特菌和沙门氏菌的生长势研究

由即食沙拉引发的食源性疾病对民众的身体健康和生命安全构成了严重威胁。为应对此问题,文章重点研究了不同储存温度条件下,即食沙拉6种主要食品基材上单增李斯特菌和沙门氏菌的生长状况。结果表明,单增李斯特菌在5℃时能够在某些食品基材,尤其是熟鸡胸肉中实现存活和繁殖;而沙门氏菌在低温条件下的任何食品基材上均无法繁殖。同时,在10℃、15℃和20℃的温度条件下,在生菜、黄瓜、紫甘蓝和鸡胸肉中,两菌均表现出了显著的增殖趋势。此外,单增李斯特菌在15℃和20℃的胡萝卜中可良好生长,在10℃下增长受限;而沙门氏菌未表现出类似变化。沙拉酱在任何温度下均不支持两种致病菌生长。希望该研究结果可为后续即食沙拉的精准风险评估提供了重要的数据支持。

Effects of Lactobacillus paracasei N1115 on gut microbial imbalance and liver function in patients with hepatitis B-related cirrhosis

BACKGROUND Hepatitis B cirrhosis(HBC)is a chronic disease characterized by irreversible diffuse liver damage and aggravated by intestinal microbial imbalance and metabolic dysfunction.Although the relationship between certain single probiotics and HBC has been explored,the impact of the complex ready-to-eat Lactobacillus paracasei N1115(LP N1115)supplement on patients with HBC has not been determined.AIM To compare the changes in the microbiota,inflammatory factor levels,and liver function before and after probiotic treatment in HBC patients.METHODS This study included 160 HBC patients diagnosed at the General Hospital of Ningxia Medical University between October 2018 and December 2020.Patients were randomly divided into an intervention group that received LP N1115 supplementation and routine treatment and a control group that received routine treatment only.Fecal samples were collected at the onset and conclusion of the 12-wk intervention period.The structure of the intestinal microbiota and the levels of serological indicators,such as liver function and inflammatory factors,were assessed.RESULTS Following LP N1115 intervention,the intestinal microbial diversity significantly increased in the intervention group(P<0.05),and the structure of the intestinal microbiota was characterized by an increase in the proportions of probiotic microbes and a reduction in harmful bacteria.Additionally,the intervention group demonstrated notable improvements in liver function indices and significantly lower levels of inflammatory factors(P<0.05).CONCLUSION LP N1115 is a promising treatment for ameliorating intestinal microbial imbalance in HBC patients by modulating the structure of the intestinal microbiota,improving liver function,and reducing inflammatory factor levels.

Effect of Pre-Processing Steps, Nitrite and Irradiation Combination Preservation of a Ready-to-Eat Spinach Relish and Sorghum Porridge Meal

The effects of pre-processing steps (washing, blanching and cooking) and combination preservation of irradiation (10 kGy) and nitrite (0, 50, 100, 150 and 200 mg·kg–1) on the survival of Clostridium sporogenes spores in a ready-to-eat (RTE) spinach relish and sorghum porridge meal were investigated. Chlorine wash (250 mg–1) reduced the C. sporogenes counts in spinach by 1.6 log cycles. Blanching following the chlorine wash caused no significant decrease in the spore counts in spinach. On the other hand, cooking significantly reduced the counts in the porridge by about 1.7 log cycles. In both components of the meal, there was a significant decrease in the Clostridia counts with increased sodium nitrite levels. However, the counts increased in the sorghum porridge component after 12 d of storage at 10℃. Cooking alone significantly reduced the final nitrite levels in both components of the meal. In both components of the meal, nitrite in combination with irradiation reduced the C. sporogenes counts to less than 10 cfu/g. A safe RTE spinach relish and sorghum porridge meal could be expected when a pre-processing, followed by a combination treatment of at least 50 mg·kg–1 sodium nitrite and a target dose of 10 kGy is applied.

Antimicrobial Resistance,Virulence Profile,and Molecular Characterization of Listeria monocytogenes Isolated from Ready-to-eat Food in China,2013-2014

We aimed to investigate the potential pathogenic profile and antibiotic resistance of Listeria monocytogenes isolated from ready-to-eat food in China.Antimicrobial resistance was determined by broth microdilution following the Clinical and Laboratory Standards Institute protocol Molecular serotyping,virulence,and resistance genes were identified using PCR.Multi-locus

Bacteriological Quality and Risk Factors for Contamination of Raw Mixed Vegetable Salads Served in Collective Catering in Abidjan (Ivory Coast)

The aim of this study was to determine the bacteriological quality of raw mixed vegetable salads served in collective catering in Abidjan and to assess the factors likely to favor contamination. An investigation was conducted to determine the practical risk of contamination. A total of 306 samples were collected and analyzed for the detection and enumeration of Enterobacteriaceae, E. coli and Salmonella according to standard microbiology methods. The most important risk factors were lack of training (96.7%), decontamination (84.0%), cross-contamination of vegetables in contact with fresh chicken or fish (76.7%) and salads that were uncovered and unprotected, thus exposed to the air and at ambient temperature for sale (97.7%). Theprevalence was 100%, 77.8% and 2.6% respectively for Enterobacteriaceae, E. coli and Salmonella. The average load of Enterobacteriaceae and E. coli was 4.93 log10 (CFU/g) and 1.89 log10 (CFU/g), respectively. Unsatisfactory microbiological quality samples were 52.3%. The results showed a failure of the sanitary quality in more than half of the products. Raising awareness in all of the workers in the food chain for vegetable salads is thus necessary to protect the health of the consumers.

Clostridium difficile in ready-to-eat foods in Isfahan and Shahrekord,Iran

Objective:To determine the prevalence and antimicrobial resistance of Clostridium difficile(C.difficile) isolated from ready-to-eat foods of Iran.Methods:From January to August 2013,a total of 368 unpacked ieady-to-eat food samples were purchased from randomly selected supermarkets,retail stores and restaurants located in Isfahan and Shahrekord,Iran and were evaluated for the presence of C.difficile.Results:C.difficile spores were detected in 5(1.36%) of the 368 samples.The highest prevalence of C.difficile was found in fasl salad(4.29%).followed by yogurt stew(2%),and olovyeh salad(0.93%).All 140 maccaroni salad and I'alafel sandwich samples were negative for C.difficile.One of the five C.difficile isolates(20%) contained tcdA,tcdB and cdtB toxin genes and four strains(80%) contained tcdA.and tcdB toxin genes.Also,among the five C.difficile isolates,only three strains were found to be toxigenic for toxin A and/or B by ELISA.Isolates were susceptible to vancomycin and metronidazole,but variably resistant to other antimicrobial drugs.Conclusions:This study,combined with studies on other food sources,suggests that widespread contamination of food is common.

Effects of γ Irradiation Dose on Sensory Acceptability of a Ready-to-Eat Spinach RELISH and Sorghum Porridge Meal

To establish the highest irradiation dose, which was still organoleptically acceptable for producing ready-to-eat (RTE) sorghum porridge and spinach mor?go meal if irradiation could be used as a preservation method. Study design: In order to produce a safe RTE meal made of these two meal components, a consumer sensory acceptability test was done on the meal irradiated at different doses of 0, 10, 20 and 30 kGy. Place and Duration of Study: Department of Food Science, University of Pretoria, between January 2000 to December 2000. Methodology: A consumer sensory acceptability test was done on the two meal components irradiated at different doses of 0, 10, 20 and 30 kGy. The sensory acceptability test on the appearance, texture, taste, and overall acceptability of the RTE meal components were evaluated. Results: The consumer overall acceptability test results showed that the two components of the meal remained acceptable up to a dose of 10 kGy (p < 0.05). The loss in appearance was observed by the panellists in the two components of the meal where the texture changed with increased irradiation doses (p < 0.05). However, irradiation had less effect on the taste of the spinach than on the sorghum porridge (p < 0.05). Overall, irradiating up to 10 kGy produced a RTE meal with acceptable sensory qualities.

An exploratory study of food safety and food handling: Examining ready-to-eat foods in independent delicatessen operations

The US Center for Disease Control and Prevention (CDC, 2009) reports that each year 76 million cases of foodborne illness occur with over 300,000 people hospitalized and 5000 deaths. This study, phase I of a continuing study, identifies key areas for food safety improvement. This study is designed as an exploratory evaluation of independently owned and operated delicatessen operations, using Escherichia coli and Staphylococcus aureus as indicators to assess food handling and the public’s risk for pathogenic contamination from commonly served ready-to-eat/take-away foods. The analysis consisted of a comprehensive strategy of laboratory testing of samples for pathogenic contamination, informal field observation of food handling procedures, and the examination of the most recent health inspection reports for each of the 18 operations visited. The deli turkey, cream cheese and lettuce were tested using bacteria indicator plates. The results showed widespread levels of contamination. Of the 54 samples tested for Escherichia coli, 26 showed positive results which are ~45% for E. coli contamination. Of the 54 samples tested for Staphy-lococcus aureus, 31 showed positive results which are ~57% for S. aureus contamination. One issue discovered while conducting the study was the lack of consistent uniform international standards of contamination tolerance levels. The informal field observations and health report analyses revealed widespread temperature violations and numerous instances of poor food handling. The study offers independent practitioners a strategy designed to improve their health inspections scores, food handling, and mitigation of operator liability. Independent operators traditionally do not enjoy the resources of centralized supervision and expert on-staff training;yet in aggregate they account for significant volume in both dollars and the quantity of product served. This study adds needed scrutiny to this important food niche.

不同交联度预糊化淀粉的制备以及在沙拉酱中的应用

为了探究预糊化淀粉在低脂沙拉酱中的运用,分析了不同交联度预糊化淀粉在黏稠度、粒径、溶油性和耐剪切性方面的差异,并研究其对低脂沙拉酱加工特性、黏稠度、外观和口感等感官评价的影响。结果表明,随着交联深度的增加,预糊化前后淀粉黏度降低,粒径增大、溶油性增强,耐剪切力增加,在应用效果上,深交联预糊化淀粉440在沙拉酱加工特性、口感和挺立度上均优于浅交联预糊化淀粉410和412,深交联预糊化变性淀粉适用于低脂沙拉酱的生产。

酵母菌处理高浓度色拉油加工废水研究

从含油土壤中筛选出适用于色拉油加工废水的酵母菌菌群，并用摇瓶试验研究了该菌群对未经预处理的高浓度含油色拉油加工废水的降解效果．采用酵母菌菌群处理总有机碳（ Ｔ Ｏ Ｃ） 含量为ρ Ｔ Ｏ Ｃ＝ ２ ５００ ｍｇ Ｌ－ １ 的色拉油加工废水，２４ ｈ 内可以去掉８５ ．２ ％ 的 Ｔ Ｏ Ｃ．酵母菌菌群在酸性条件下（ｐ Ｈ３ 左右） 表现出更好的处理效率，反应温度升高时 Ｔ Ｏ Ｃ 去除率有降低的趋势．结果表明。

低脂素食沙拉酱稳定体系研究

目的:研究制作低脂素食沙拉酱的稳定体系。方法:以马铃薯全粉为基础材料,以感官评价分数和质构参数作为指标。在单因素试验的基础上,以单甘酯、黄原胶和没食子酸丙酯的含量为自变量,以硬度、黏度、弹性、内聚力和感官评价分数为响应值进行多组响应面分析,确定乳化剂、增稠剂、抗氧化剂对产品的质构参数和感官评分的影响。结果:响应面试验回归模型具有显著性,方程对试验拟合较好;确定最优的添加剂含量为单甘酯0.20%,黄原胶0.15%,没食子酸丙酯0.008%。结论:验证试验中,所测产品硬度为124.535g,黏度为422.586g·s,弹性为0.953,内聚力为0.799,感官评分为90分,与模型预测值基本一致,依照此配比加工出的沙拉酱口感润滑、组织细腻,整体体系稳定性较好。

利用Box-Behnken响应面法优化川明参药膳风味沙拉酱的配方工艺

为了提高药食两用作物-川明参在川菜中的应用价值,在单因素实验的基础上,选取川明参粉、蛋黄酱、花生酱、白糖、蜂蜜、橄榄油、芥末油的添加量为响应因素,以感官评价为响应值,采用Box-Behnken响应面分析法优化最佳风味配方工艺。结果表明:各因素质量之比为高级清汤∶川明参粉为1.52∶1(g/g),蛋黄酱∶花生酱为7.82∶1(g/g),橄榄油∶芥末油为3.93∶1(g/g)时,感官评价分数最高为95.91。该研究可为普及消费者营养保健知识和创新川菜药膳风味凉菜的标准化制作工艺提供参数借鉴。

食源性大肠杆菌耐药性检测

采用美国临床实验室标准化委员会(National Committee of Clinical Laboratory Standard简称NC-CLS)推荐的琼脂稀释法,以大肠埃希氏菌ATCC25922、粪肠球菌ATCC29212和金黄色葡萄球菌ATCC29213为质控菌株,对411株分离自鸡肉和凉拌菜的大肠杆菌进行了6大类共12种抗生素的药敏性检测。结果表明受试菌株对四环素的耐药率(98.3%)最高,其次是链霉素(71.3%)、奈定酮酸(68.4%)、阿莫西林(67.6%)、氨苄青霉素(61.8%)、环丙沙星(50.6%)、氯霉素(48.4%)、卡那霉素(40.6%)、庆大霉素(36.7%),所有受试菌株对阿米卡星的敏感性最强,仅有11.9%(49)的耐药率,其次是头孢西丁(14.1%)和头孢哌酮(29.9%)。247(60.1%)株分离菌表现5重以上耐药性,其中鸡肉分离株占236株。

酵母菌处理系统中氮缺乏引起的污泥膨胀控制

研究了酵母菌处理色拉油加工废水系统中投加氮源对处理效果的影响及对污泥膨胀的恢复作用 .批量实验结果表明 :①添加氮源有助于提高去除效果 ,碳氮比 (COD/N)为 5 0 /1～ 2 0 /1的条件下 ,油去除率最高 ,达 90 %以上 ;②添加氮源能够改善污泥沉降性 ,COD/N比为 5 0 /1、2 0 /1时污泥沉降性明显优于 1 0 0 /1、2 0 0 /1和不加氮的条件 .连续试验中按COD/N为 2 0 /1添加氮源 ,污泥体积指数 (SVI)稳定在 1 0 0～ 2 0 0 ,油和COD去除率分别达95 %和 90 %以上 .

陕西关中畜禽肉及凉拌菜中沙门氏菌污染分析

为了解陕西省关中地区食品中沙门氏菌的污染状况及分布,初步确定污染沙门氏菌的高危食品种类,为沙门氏菌检测、监测和食品安全控制提供理论依据。本研究按照GB/T 4789.1-2003规定的方法采集陕西省西安、杨凌和宝鸡等地超市和农贸市场的零售肉样品443份,凉拌菜样品209份;使用选择性培养基分离沙门氏菌,采用PCR技术对沙门氏菌进行鉴定。结果发现5大类食品中,鸡肉被沙门氏菌污染的状况最为严重(69.9%),其他食品污染率由高到低依次为羊肉(55.3%)、牛肉(30.1%)、猪肉(19.4%)和凉拌菜(9.6%);肉类食品的污染状况(45.2%)远高于凉拌菜(9.6%);从超市采集的零售肉样品沙门氏菌污染率(46.8%)低于从农贸市场采集的零售肉样品(54.6%);西安地区零售肉沙门氏菌污染率最高,其次分别为杨凌和宝鸡地区;杨凌地区即食凉拌菜沙门氏菌污染率最高(6.7%),其次分别为宝鸡(2.9%)和西安(0%)。从结果可得出,陕西关中地区的零售肉和即食凉拌菜已在不同程度上受到沙门氏菌污染。