奶粉伴侣中微生物污染特点分析

目的:了解婴幼儿经常食用的奶粉伴侣中微生物的污染状况。方法:2016年在我国8个省(直辖市)采集奶粉伴侣864份,按照食品安全国家标准方法检测菌落总数、大肠菌群、阪崎肠杆菌、单核细胞增生李斯特菌、金黄色葡萄球菌和沙门氏菌。结果:1.04%(9/864)的奶粉伴侣菌落总数10~4cfu/g,0.12%(1/864)大肠菌群10~2cfu/g,未检出单核细胞增生李斯特氏菌、金黄色葡萄球菌和沙门氏菌,但1份样品检出阪崎肠杆菌。结论:奶粉伴侣微生物污染水平较低。     

2017年楚雄地区餐饮业过桥米线微生物污染状况调查分析

目的 了解楚雄地区过桥米线微生物污染状况, 获得地域代表性数据。方法 按照《2017年云南省食品安全风险监测方案》, 采用国家标准规定的检测方法, 对60份过桥米线样品进行菌落总数、大肠菌群、霉菌计数、沙门氏菌、蜡样芽胞杆菌、变形杆菌、金黄色葡萄球菌、单核细胞增生李斯特杆菌8个微生物指标检测。结果 60份过桥米线样品中,菌落总数检出率83.33%(50/60), 大肠埃希氏菌计数检出率40.00%(24/60), 霉菌计数检出率65.00%(39/60); 致病菌总检出率33.33%(20/60), 共检出食源性致病菌23株, 检出菌株数(检出率)分别是: 蜡样芽胞杆菌9株(15.00%)、金黄色葡萄球菌6株(10.00%)、变形杆菌5株(8.33%)、沙门氏菌3株(5.00%), 单核细胞增生李斯特杆菌未检出。结论 楚雄地区过桥米线微生物污染严重, 应加强监管, 控制食用安全风险; 同时应尽快制定云南省地方特色食品过桥米线的食品质量或安全标准。     

贵州某地自制腐乳微生物污染情况研究

运用随机采样法,在贵州某地农贸市场采集到白腐乳、红油腐乳、霉豆腐各两份。根据食品微生物学检验的相关检测方法,检测菌落总数、大肠菌群、沙门氏菌、金黄色葡萄球菌、霉菌、蜡样芽孢杆菌、大肠埃希氏菌O157:H7/NM、单核细胞增生李斯特氏菌和志贺氏菌。结果显示,菌落总数、大肠菌群、蜡样芽孢杆菌的检出率为100%,霉菌检出率为66.67%,金黄色葡萄球菌检出率为33.33%;致病菌定性检测中,大肠埃希氏菌O157:H7/NM检出率为33.33%,沙门氏菌检出率为16.67%,单核细胞增生李斯特氏菌检出率为16.67%,6个样品中均未检测出志贺氏菌。通过本次试验初步评估自制腐乳的安全性,以期为贵州腐乳发酵中常见微生物污染及食用安全性评价提供参考。     

广州市售鲜鸡肉微生物污染状况调查

为了了解广州市市售生鲜鸡肉的微生物污染状况,并为建立食物污染及中毒的预警系统提供数据基础。2009年10月到12月从广州市天河区5个农贸市场和5个超市采集鲜鸡肉50件,对其表面进行了菌落总数、嗜冷菌数、大肠菌群、沙门氏菌、李斯特菌、金黄色葡萄球菌的定性、定量检测。结果表明,农贸市场鸡肉产品的菌落总数和大肠菌群数比超市的高;而超市鸡肉产品的嗜冷菌数要比农贸市场的高。农贸市场沙门氏菌检出率为44.0%、单增李斯特菌检出率为36.0%、金黄色葡萄球菌检出率为36.0%。超市沙门氏菌检出率为28.0%、单增李斯特菌检出率为28.0%、金黄色葡萄球菌检出率为36.0%。总体上超市的鲜鸡肉微生物污染程度比农贸市场的低。     

2015~2017年广州市某食品厂低温肉灌肠生产加工过程微生物污染状况及风险分析

目的 了解低温肉灌肠生产加工过程中主要食源性致病菌的污染状况, 分析生产加工过程存在的微生物污染风险。方法 采集2015～2017年广州市某食品厂低温肉灌肠生产加工过程不同环节样品362份, 按食品安全国家标准规定的检测方法对菌落总数、大肠菌群、沙门氏菌、金黄色葡萄球菌和单核细胞增生李斯特氏菌进行检测, 并对结果进行分析。结果 生产加工过程采集的样品沙门氏菌、金黄色葡萄球菌和单核细胞增生李斯特氏菌检出率分别为1.10%(4/362)、0.55%(2/362)和25.97%(94/362)。原辅料、中间产品、成品和终产品单核细胞增生李斯特氏菌检出率分别为48.00%、39.13%、20.00%和0.00%, 差异有统计学意义(χ2=22.57, P<0.05)。结论 低温肉灌肠生产加工过程存在微生物污染风险, 以单核细胞增生李斯特氏菌污染风险最高, 二次杀菌可有效降低低温肉灌肠终产品微生物污染。     

新疆地区部分食品微生物污染检测结果分析

目的分析近两年新疆地区部分食品种类微生物检测结果,了解新疆地区食品的微生物污染状况,为食品安全监督管理部门提供科学依据。方法根据GB 4789系列标准方法的要求,对新疆地区抽送检的256批预包装熟肉制品、297批蜂蜜、89批饮料、42批发酵乳、93批糕点面包、96批冷冻饮品、37批速冻米面食品(包括10批生制品)进行菌落总数、大肠菌群、金黄色葡萄球菌、沙门氏菌、单核细胞增生李斯特菌、大肠埃希氏菌O157:H7/NM、乳酸菌、霉菌和嗜渗酵母菌的微生物检测。结果 10批预包装熟肉制品、6批蜂蜜、9批冷冻饮品、6批饮料、1批速冻米面食品菌落总数超标;6批冷冻饮品和1批饮料大肠菌群超标;3批蜂蜜嗜渗酵母菌数超标;2批蜂蜜霉菌数超标;1批饮料酵母菌数超标;2批速冻米面食品(生制品)金黄色葡萄球菌超标;3批冷冻饮品检出单核细胞增生李斯特菌。除发酵乳对菌落总数没有明确要求和糕点面包菌落总数未超标外,其他产品均出现菌落总数超标问题,其中饮料、冷冻饮品合格率低于95%,应划类于高风险产品;冷冻饮品和饮料还存在大肠菌群超标问题;冷冻饮品检出单核细胞增生李斯特菌,速冻米面食品(生制品)检出金黄色葡萄球菌,说明这2类食品致病菌检出风险较高。结论建议食品企业加强卫生管理,查找超标原因,采取有效措施确保食品安全,建议监管部门对微生物污染率较高的产品继续加强监管力度,以保障食品安全。     

成都市散装糕点微生物质量情况调查与分析

目的检测成都市散装糕点微生物的污染情况,分析主要污染来源以及风险点并提出改进措施。方法参考GB 7099-2015《食品安全国家标准糕点、面包》中的微生物要求对市场上销售散装糕点进行菌落总数、大肠菌群、霉菌以及致病菌(沙门氏菌、金黄色葡萄球菌)检测,并对含肉制品散装糕点进行单核细胞增生李斯特氏菌检测。对直接接触食品的包装材料进行大肠菌群检测。结果散装糕点菌落总数不合格率为63%,大肠菌群不合格率40%,霉菌不合格率为16%。均未检出致病菌。结论成都市散装糕点微生物不合格率较高,散装糕点生产销售企业也存在一定食品安全问题,监管部门对该行业应加强管理力度。     

灌肠类熟肉产品生产环节微生物污染风险评估

根据国家食品安全标准检测灌肠类熟肉制品生产过程各环节环境、原辅料及产品的菌落总数、大肠菌群、亚硫酸盐还原梭状芽胞杆菌、金黄色葡萄球菌、沙门氏菌和单核细胞增生李斯特菌,同时测定致病菌的耐药性。结果显示:原辅料和中间产品受大肠菌群和厌氧亚硫酸盐还原梭状芽孢杆菌的污染较重;生产用水和终产品的卫生状况良好。环境和原辅料中均有致病菌检出,主要为金葡菌和沙门氏菌。分离出的沙门氏菌和金葡菌耐药严重,分别有88.89%的沙门氏菌和85.71%的金葡菌具有多重耐药性。说明灌肠类熟肉制品生产过程极易受到大肠菌群、厌氧亚硫酸盐还原梭状芽孢杆菌、金葡菌和沙门氏菌的污染,生产原辅料是主要的微生物污染来源。     

江苏省徐州市市售发酵与非发酵豆制品微生物污染调查

目的 调查江苏省徐州市市售豆制品微生物污染情况。方法 采集发酵、非发酵豆制品86份, 按照GB 4789进行大肠菌群、菌落总数(非发酵豆制品)、蜡样芽胞杆菌、金黄色葡萄球菌的定量和单核细胞增生李斯特氏菌、沙门氏菌的定性检测。结果 大肠菌群检出率为34.88%, 蜡样芽胞杆菌为12.79%, 金黄色葡萄球菌为1.16%, 其余致病菌均未检出。非发酵豆制品中大肠菌群检出率为65.91%, 计数>103 CFU/g占52.27%, 散装较预包装样品检出率高, 差异有显著意义(P<0.05); 菌落总数>105 CFU/g占75.00%; 蜡样芽胞杆菌检出率为6.82%, 104 CFU/g(均<105 CFU/g)占4.55%; 金黄色葡萄球菌检出率为2.27%。发酵类豆制品中大肠菌群检出率为2.38%, 蜡样芽胞杆菌为19.05%, 104 CFU/g占7.14%(均<105 CFU/g); 预包装、散装样品蜡样芽胞杆菌检出率差异无显著意义(P>0.05)。发酵、非发酵豆制品中大肠菌群检出率差异均有显著意义(P<0.05); 发酵豆制品合格率为97.62%, 非发酵豆制品合格率为11.36%, 差异有显著意义(P<0.05)。结论 徐州市豆制品中非发酵类卫生指标菌污染较为严重, 应加强卫生监督。     

中温协同超高压处理对梨汁中微生物的影响

本文研究了处理压力和协同温度对梨汁中菌落总数、霉菌和酵母菌以及大肠菌群存活量的影响。处理压力为大气压力到500MPa、协同温度为室温(19℃)到58℃、保压时间为10min、梨汁pH5(梨汁自然酸度)。实验结果表明:(1)在室温、保压时间为10min的条件下,当处理压力达到500MPa,菌落总数为50cfu/ml;压力为400MPa,霉菌和酵母菌存活量为10cfu/ml,大肠菌群则未被检出。(2)在压力为450MPa、保压时间为10min的条件下,协同温度≥29℃时,梨汁中菌落总数为70cfu/ml;霉菌和酵母菌未被检出;室温下高压处理大肠菌群即未被检出,完全达到国家食品卫生标准。     

紫菜花生营养调味酱

以紫菜全菜30％，花生原酱30％、芝麻原酱10％，食盐5％为基本原料，可调制出富含碘、钙和蛋白质的调味品，能有效地补充人体对碘、钙的需要。     

Minimally processed vegetable salads: microbial quality evaluation

The increasing demand for fresh fruits and vegetables and for convenience foods is causing an expansion of the market share for minimally processed vegetables. Among the more common pathogenic microorganisms that can be transmitted to humans by these products are Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella. The aim of this study was to evaluate the microbial quality of a selection of minimally processed vegetables. A total of 181 samples of minimally processed leafy salads were collected from retailers in the city of Sao Paulo, Brazil. Counts of total coliforms, fecal coliforms, Enterobacteriaceae, psychrotrophic microorganisms, and Salmonella were conducted for 133 samples. L. monocytogenes was assessed in 181 samples using the BAX System and by plating the enrichment broth onto Palcam and Oxford agars. Suspected Listeria colonies were submitted to classical biochemical tests. Populations of psychrotrophic microorganisms >10(6) CFU/g were found in 51% of the 133 samples, and Enterobacteriaceae populations between 10(5) and 106 CFU/g were found in 42% of the samples. Fecal coliform concentrations higher than 10(2) CFU/g (Brazilian standard) were found in 97 (73%) of the samples, and Salmonella was detected in 4 (3%) of the samples. Two of the Salmonella-positive samples had <10(2) CFU/g concentrations of fecal coliforms. L. monocytogenes was detected in only 1 (0.6%) of the 181 samples examined. This positive sample was simultaneously detected by both methods. The other Listeria species identified by plating were L. welshimeri (one sample of curly lettuce) and L. innocua (2 samples of watercress). The results indicate that minimally processed vegetables had poor microbiological quality, and these products could be a vehicle for pathogens such as Salmonella and L. monocytogenes.     

Oil Migration in 2-Component Confectionery Systems

ABSTRACT:  Oil migration from high oil content centers into chocolate coatings results in product quality changes. The objective of this study was to monitor and model peanut oil migration in 2-layer systems of increasing phase complexity. Three 2-layer systems were prepared: peanut oil/cocoa butter; peanut butter paste/cocoa butter; and peanut butter paste/chocolate. Magnetic resonance imaging was used to measure liquid oil signal as a function of position over a storage time of 193 days at 25 °C. The 3 types of samples exhibited appreciably different patterns of oil migration. The peanut oil/cocoa butter samples had mass transfer typical of oil being absorbed into a liquid/solid region. The peanut butter paste/cocoa butter magnetic resonance profiles were characterized by mass transfer with a partition coefficient greater than unity. The peanut butter paste/chocolate samples exhibited a time-dependent peanut oil concentration at the interface between the chocolate and peanut butter paste. The spatial and temporal experimental data of the peanut butter paste/chocolate samples were modeled using a Fickian diffusion model, fitting for the effective diffusivity. Values of the diffusivity for the 6 chocolate formulations ranged from 1.10 to 2.01 × 10⁻¹³ m²/s, with no statistically significant differences.     

Development of a Chocolate Flavored Peanut Beverage

Nine chocolate-flavored peanut beverages (CFPB) were prepared using peanut protein isolate as source of protein and analyzed for physical-microbiological-sensory qualities. The quality attributes such as color, aroma, viscosity, and flavor of CFPB were similar to that of commercial chocolate milk. The total aerobic populations of the beverage before and after refrigeration for 7 days were less than 10 and 200 colonies/g, respectively, and no coliform bacteria was detected in this product. Sensory evaluation and response surface methodology indicated that optimum formulation of CFPB was obtained by using 3.5% protein (from peanut protein isolate), 3.5% butter, 8% sugar, 0.7% cocoa powder, 0.1% stabilizer, and water. Consumer study of the CFPB revealed that all sensory characteristics were acceptable in the range of like to extremely like.     

基于LAMP技术检测纯芝麻酱中的多种植物源性成分

环介导恒温扩增技术(loop-mediated isothermal amplification,LAMP)是一种较为新型的恒温DNA扩增技术,有着灵敏度高、特异性好、方便快捷的优点。通过设计特异性引物,建立了一套利用LAMP技术检测芝麻酱中芝麻、花生、葵花籽源性成分的方法,该方法特异性好,能够在60min以内检测低至0.1%的农作物混合物中芝麻、花生、葵花籽源性成分,具有较高的灵敏度。应用试验建立的方法,结合大豆、玉米、水稻内源性基因检测试剂盒对市场流通环节41份标识为纯芝麻酱的样本进行检测分析,结果显示其中18份检出花生成分,2份检出大豆成分,1份检出葵花籽成分,所有样品均未检出水稻、玉米成分。     

2015~2017 年烟台市某肉制品生产企业的生产 加工环节致病菌检测及分布特征分析

目的 了解2015~2017 年烟台市熟肉制品各生产环节致病菌污染状况及病原分布特征。方法 监测项目为菌落总数、大肠菌群、金黄色葡萄球菌、李斯特菌属、沙门氏菌, 检测方法依据《食品安全国家标准 食品微生物学检验》各项标准进行, 空气参照GB/T 16294-2010《医药工业洁净室沉降菌的测试方法》。结果 427份样品中, 检出致病菌75 株, 致病菌总体污染率为17.56%。单核细胞增生李斯特氏菌35 株, 其中25 株来源于环境样品, 占总检出率的71.42%; 金黄色葡萄球菌26 株, 16 株来源于原辅料, 占总检出率为23.19%; 沙门 菌19 株, 全部来源于原辅料。结论 金黄色葡萄球菌、沙门氏菌的主要检出来源于原辅料样品,单核细胞增生李斯特氏菌主要检出来源于环境样品,因此提高原辅料采购管理要求,并加强原辅料质量管理,同时加强对生产环境消毒力度。     

Microbial evaluation of selected fresh produce obtained at retail markets

The microbial quality of five types of fresh produce obtained at the retail level was determined by standard quantitative techniques. These techniques included aerobic plate count (APC), total coliform counts, Escherichia coli counts, and yeast and mold counts. Three different methods were used to determine total coliform counts, which consisted of MacConkey agar plate counts, Colicomplete most probable number counts, and Petrifilm E. coli (EC) plate counts. The mean APCs for sprouts, lettuce, celery, cauliflower, and broccoli were 8.7, 8.6, 7.5, 7.4. and 6.3 log10 CFU/g, respectively. MacConkey agar counts indicated that 89 to 96% of the APCs consisted of gram-negative bacteria. Yeast and mold counts were in a range expected of fresh produce. Fresh produce was also analyzed for human pathogens. Samples were analyzed for Staphylococcus spp., Bacillus spp., Salmonella spp., Listeria spp., and Campylobacter spp. One isolate of Staphylococcus was found to be enterotoxigenic, and one species of Bacillus was also toxigenic. Neither Salmonella spp. nor Campylobacter spp. were detected in any of the produce samples. A variety of Listeria spp., including Listeria monocytogenes, were found in fresh produce.     

Possible Mechanism behind the Hard-to-Swallow Property of Oil Seed Pastes

Roasted and crushed oil-rich seeds, such as sesame paste and peanut butter, both share a common structure and elicit an apparent sensation of thickening in the mouth. Working with sesame paste, as an example, the force needed to compress sesame paste:water mixtures peaked at 25% added water. The adhesive force required to pull a plunger from the surface was bimodal with peaks at around 15 and 25% hydration. It is postulated that when introduced to the mouth, water from the saliva is absorbed by the paste leading to a hard, adhesive material that sticks to the palate and the tongue, making these materials hard to swallow. It is hypothesized that the shared hard-to-swallow behaviour exhibited by other oil seed pastes/butters is due to a similar hydration process in the mouth.     

Microbiological evaluation of sprouts marketed in Mumbai, India, and its suburbs

A study was undertaken to assess the microbiological quality of sprouts marketed in Mumbai and its suburbs. A total of 124 sprout samples of four different legumes--mung (Phaseolus aureus), matki (Phaseolus aconitifolius), chana (Cicer arietinum), and vatana (Pisum sativum)--were analyzed over a period of 12 months for aerobic plate counts, coliforms, yeast and mold counts, staphylococci, Salmonella, Listeria monocytogenes, Escherichia coli, E. coli O157:H7, and coagulase-positive Staphylococcus aureus. Aerobic plate counts ranged from 7.6 to 8.9 log CFU/g, coliform counts ranged from 5.4 to 7.9 log CFU/g, yeast and mold counts ranged from 3.6 to 7.3 log CFU/g, and staphylococci counts ranged from 3.3 to 6.6 log CFU/ g. Nonpathogenic E. coli was detected in 13% of the mung, 26% of the matki, 40% of the chana, and 19% of the vatana samples. Salmonella Typhimurium was detected in 21% of the mung, 40% of the matki, and 4% of the chana samples. Salmonella Dublin was detected in 2% of the mung samples, and Salmonella Washington was detected in 4% of the matki samples. L. monocytogenes and E. coli O157:H7 were not detected in any of the samples examined. Coagulase-positive S. aureus was detected in 4% of the mung, 11% of the matki, and 4% of the chana samples. The results indicated that the marketed sprouts were of poor microbiological quality; therefore, further processing, such as radiation processing, is needed to ensure their safety.