Fungal Population Dynamics in Ready-to-eat Salads During a Shelf-life in Italy

The aim of this work was to investigate the fungal population dynamics in ready-to-eat bagged samples of rocket （Diplotaxis spp.）, lettuce baby leaf （Lactuca sativa L.） and ＂songino＂ （Valerianella olitoria L.） during a shelf-life, in order to evaluate the effects of the storage length and season of production on the spoilage processes. The incidence of toxigenic moulds was particularity studied in order to evaluate a potential production of mycotoxins and allergenic conidia. A total of 900 samples collected from 10 Italian trademarks were analyzed at the 2nd, 5th and 8th day after the packaging in the spring and summer. A very high number of fungi was found and a great variability of moulds and yeasts at the 1 st day of sampling was observed. Regarding to season of production, any seasonal effect on the moulds and yeasts has been observed, but the moulds detected belonged to different species in relation to season. Regarding to storage length, the yeasts and moulds did not showed significant variations during a shelf-life. In relation to vegetable species, the lettuce resulted always less contaminated with respect to other salads, and the rocket presented 1-2 Log cfu/g of increasing in the level of moulds. Regarding to fungi species, the yeasts were significantly predominant respect to moulds. Finally, the toxigenic moulds Aspergillusflavus and Penicillium italicum were found in all the types of salad in the summer, and their growth during the storage at low temperature represented a potential hazard for the mycotoxins and allergenic conidia production in these commodities.

Bacteriological Assessment of the Quality of Raw-mixed Vegetable Salads Prepared and Sold by Street Food Vendors in Korle-Gonno, Accra Metropolis, Ghana

It is known that raw-mixed vegetable salads are essential part of people＇s diet all around the world. These vegetables salads are consumed raw and often without heat treatment or thorough washing. Raw-mixed vegetable salads therefore can serve as vehicle for the transmission of pathogenic microorganisms associated with human diseases. The aim of this study was to isolate and analyze the common bacterial pathogens associated with raw-mixed vegetable salads prepared and sold by street food vendors in Korle-Gonno, Accra, Metropolis, Ghana. A total of 75 different raw-mixed vegetable salads were sampled from the open places and were subjected to bacteriological analysis using standard Food and Agriculture Organization （FAO） of the United Nations （UN） total aerobic plate count method. A total mean colony count of bacteria ranged 0.87-5.6 log10 CFU/g was isolated. Escherichia coli （35%）, Staphylococcus aureus （33%）, Klebsiella sp. （17%）, and Bacillus sp. （15%） were the bacteria isolated from the various raw-mixed vegetables salads investigated. This study has shown that all the raw-mixed vegetable salads sampled from Korle-Gonno, Accra Metropolis, Ghana had a high bacterial contamination and their persistence and proliferation is a reflection of poor hygienic practices by the street food vendors. The use of unsafe or contaminated water to irrigate the vegetables when growing on the farm or garden could also be a contributing factor.

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.

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.

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

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.

Stability of Bitter Orange Juice-Olive Oil Salad Dressings Stabilized with Polysaccharides

Emulsifying properties of bitter orange （Citrus aurantium） juice-olive oil salad dressings stabilized with different polysaccharides were investigated. Oil-in-water emulsions （50：50, v/v） were prepared with bitter orange juice-olive oil in the presence of various concentrations （0.1%-1.0%, w/v） of pectin or guar gum or iota-（t-）carrageenan and then these emulsions were homogenized. Emulsion activity index （EAI） and emulsion stability index （ESI） were determined spectrophotometrically by measuring time-dependent changes in turbidity. Creaming stability of emulsions was followed by visual observation of serum layer with respect to time. Microstructures of emulsions were examined by using polarized light microscopy. The addition of polysaccharides improved emulsion stability and emulsions containing higher amounts of polysaccharide were more stable against creaming. Microscopic observations showed that emulsions containing polysaccharides had small droplets as compared to that of emulsions without polysaccharides and emulsions were flocculated due to the presence of polysaccharides. Larger droplets and creaming were observed when the polysaccharide concentration was not sufficient for coverage.

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.

茶籽油基低脂沙拉酱的工艺配方研究

利用茶籽油部分替代传统沙拉酱中的大豆油,并添加变性淀粉制备茶籽油基低脂沙拉酱,研究产品配方和加工工艺条件。通过单因素试验和正交试验确定茶籽油基低脂沙拉酱的最优工艺配方为沙拉酱用油量30%,茶籽油与大豆油比例为4∶6,羟丙基二淀粉磷酸酯添加量2.5%,黄原胶添加量0.35%,蛋黄液添加量10%,白砂糖添加量5%,食盐添加量1%,白醋添加量4%,柠檬酸添加量0.15%,山梨酸钾添加量0.1%,乙二胺四乙酸二钠添加量0.01%,β-胡萝卜素添加量0.02%,最优工艺配方下制作的沙拉酱具有良好的感官品质,与市售沙拉酱硬度、黏聚性及黏度都很接近。

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。

蛋清蛋白微粒基低脂沙拉酱流变学特征及品质优化

本实验以蛋清蛋白微粒(egg white protein microparticles,EWPM)为代脂基质,研究EWPM/黄原胶(xanthan gum,XG)共混质量分数、pH值、氯化钠含量、糖含量、均质条件等对超低脂沙拉酱产品流变学特性的影响规律。研究发现,XG对EWPM基超低脂沙拉酱具有显著的增稠效果,然而含量过高会导致低脂沙拉酱恢复性下降。基础调味组分对超低脂沙拉酱品质的影响存在较大差异,pH值和盐对体系黏度影响较大,糖添加量对黏度的影响相对较小。适度的胶体磨均质转速和均质时间可以减小产品的粒径,增加其内部均一性,显著提高产品的整体黏度。本实验以沙拉酱流变学行为调控为重点,为低脂沙拉酱的研究提供一个更加明确的工艺优化方向。

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。

三赞胶在低脂沙拉酱中的应用研究

文章探究了三赞胶的基本结构与性质,红外光谱和流变性质分析结果表明,三赞胶分子结构中含有大量的缔合羟基,并且具有α-和β-两种构型的糖苷键连接的以吡喃糖环为骨架的结构,符合多糖的结构特征,当三赞胶的浓度高于0.3%时表现出弱凝胶结构。通过对不同浓度的三赞胶对低脂沙拉酱的流变性质、质构特性、粒径分布、感官评价和微观结构的影响进行研究,结果表明,三赞胶由于其增稠性、乳化性及一定的弱凝胶性能可以保持低脂沙拉酱乳状液的稳定性,同时也能保持与高脂肪产品具有相似的口感,是良好的脂肪替代物。

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.

复合茶油低脂沙拉酱的研制

以复合茶油、蛋清、蜂蜜、白醋、黄原胶、羧甲基淀粉为主要原料研制复合茶油低脂沙拉酱,以感官评分和质构特性为考察指标,通过单因素试验和正交试验,确定复合茶油低脂沙拉酱的最佳工艺配方为复合茶油添加量为30.0 g(m_(茶油):m_(牛油果油)=2∶1)、黄原胶添加量为1.1 g、羧甲基淀粉添加量为4.0 g、复合凝胶pH为11.0、复合凝胶温度为80℃、蛋清添加量为20.0 g、蜂蜜添加量为6.0 g、白醋添加量为5.0 g。此配方制成的沙拉酱色泽光亮、乳白,成型良好,无析油现象,细腻可口,蛋香味足,层次丰富。茶油含有15.85 mg/100 g茶多酚,且利用黄原胶-羧甲基淀粉复配凝胶部分替代复合茶油,使得此款沙拉酱的脂肪含量仅为35.58%,低于市售沙拉酱(67%),符合人们对于营养、低脂、保健食品的要求。

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。