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...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.展开更多
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 c...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.展开更多
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 bitte...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.展开更多
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...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。展开更多
文摘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.
文摘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.
文摘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.
文摘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。
