不同灭菌处理对“冷蒸”微生物指标及感官品质的影响

为研究不同灭菌处理对"冷蒸"的微生物指标及感官品质的影响,采用臭氧、巴氏灭菌以及两者组合对样品进行处理。试验结果表明:臭氧与巴氏灭菌的结合(10 min+80℃/20 min)处理的感官品质评分较高,该处理在温度为4℃下贮藏30 d后,其细菌总数、大肠菌群、酵母菌总数分别为20 cfu/g、3 cfu/g、10 cfu/g以及无霉菌生长。结论:经臭氧灭菌10 min与巴氏灭菌(80℃/20 min)相结合对样品处理后,其产品感官品质得分较高,且将其贮藏时间从10 d延长至30 d。     

啤酒包装过程质量控制

<正>包装过程质量控制的好坏直接影响着产品的外观质量和内在质量。给这一个生产过程设立关键控制点,进行产品质量控制。洗瓶、灌装压盖、杀菌、贴标是四个重要的关键控制点。1洗瓶洗瓶合格率要求达到98%以上,洗后瓶内外光洁,无残标、倒置1分钟残留水滴≤3滴,酚酞检验不变色,蒸馏水检验无残留纸纤维,空瓶微生物菌落总数≤50cfu/ml,大肠菌群3个/ml。为达到此目标,要做到:1)瓶源:进洗瓶机的瓶子无异型瓶、油瓶、水泥瓶、霉斑严重和特脏的瓶,带盖瓶,特脏     

臭氧水润麦生产低菌化小麦粉的研究

目的优化臭氧水润麦生产低菌化小麦粉工艺条件。方法用不同浓度臭氧水和温度润麦,并对小麦粉进行微生物和品质指标检测。结果 20℃润麦时,浓度为5.5 mg/L的臭氧水能显著降低小麦粉中微生物含量(P0.05),且对小麦粉脂肪酸值和色彩色差值等品质指标无负面影响;同一臭氧水浓度润麦时,温度与小麦粉中微生物含量之间基本呈极显著的正相关(P0.05),温度较低时,对小麦粉品质指标未产生负面影响。综合考虑减菌效果和对小麦粉品质的影响,润麦时选择臭氧水浓度为5.5 mg/L,温度为10℃,在此工艺下小麦粉中的细菌总数、需氧芽孢数和霉菌量分别为310、210、230 cfu/g,蜡样芽孢杆菌和大肠杆菌均10 cfu/g。结论本方法能够生产低菌化小麦粉。     

蟹糊微生物控制方法的探讨

采用臭氧、白酒和辐照3种方法对蟹糊原料、半成品及成品进行杀菌处理,以实现蟹糊加工和储运过程中对微生物的控制. 结果表明:用臭氧(质量浓度6mg/L)浸泡蟹糊原料12min,其原始菌落总教由4.86×105cfu/g降至3 500cfu/g,达到国家标准GB10136-2005.白酒对蟹糊的抑菌试验表明:浸泡时间对试验结果的影响极显著(FB=**21.16),其次为白酒浓度(FA=5.35),浸泡温度(Fc=0.76)最不显著.白酒杀菌优方案为A3B3C1,原料菌落总数从1.2×105cfu/g降至864 cfu/g.辐照对蟹糊产品的抑菌试验表明:2、4、6、8 kGy剂量的辐照处理,原始菌落数由2.09×104分别降为213、56、23、7cfu/g;辐照过的产品在贮存期内菌落总数有上升趋势,低温贮藏有利于抑制产品菌落总数上升.     

浅析配制酒卫生标准中制订微生物指标的必要性

为提高配制酒的卫生质量,延长保质期限,从原料、生产工艺和生产环境对配制酒的污染,以及样品的检验结果,说明了制定配制酒中微生物指标的必要性和可行性。建议将指标定为：菌落总数（cfu/ml）≤50,大肠菌群（MPN/100ml）≤3 。     

西安工程大学校园不同区域空气中微生物含量

采用自然沉降法对西安工程大学校园内的学生公寓、食堂、教室等具有代表性的10个不同功能区域空气中微生物进行了监测与分析.结果表明,除食堂和女生公寓外;男生公寓和教室空气中微生物总数最多,分别达到1.4×104cfu/m3和1.1×104cfu/m3;绿化区和图书馆空气中微生物总数最少,分别为1.7×103cfu/m3和1.9×103cfu/m3,为清洁;空气微生物含量不仅与地面人类活动关系密切,而且还与天气变化、风力大小、气流和植被等有关.通过了解校园空气微生物的污染情况,提出相应的措施以改进校园内的空气质量状况.     

模糊评价与响应面分析法结合优化糯玉米饮料的配方

以糯玉米为原料,结合糯玉米饮料传统加工工艺流程,针对料液比、糖酸比和稳定剂种类及其浓度,在单因素试验基础上,通过响应面分析法与模糊评价法结合确定出饮料的最佳配方,并对最优配方的糯玉米饮料进行营养成分分析和微生物分析。结果表明糯玉米饮料的最佳配方为:料液比1:3.19、糖酸比25.66:1,稳定剂种类及其浓度为0.15%海藻酸钠+0.1%魔芋胶。该糯玉米饮料中含蛋白质0.736g/100ml、总固形物9.8g/100ml、可滴定酸度(总酸)2.08g/kg、脂肪1.7g/100g;饮料中菌落总数90cfu/ml、大肠菌群数3个/100ml、霉菌和酵母菌数15cfu/ml。     

臭氧处理对脱水蒜片减菌效果及品质的影响

为了降低脱水蒜片成品中菌落总数,将脱水蒜片置于密闭的空间中,研究臭氧浓度和处理时间对脱水蒜片的杀菌效果和品质的影响。结果表明:脱水蒜片中菌落总数随着臭氧浓度的增大、处理时间延长而显著减少(p0.05)。当臭氧浓度为30 mg/m3,处理时间为90 min,减菌效果最佳,此时菌落总数为3.98 log(cfu/g),较对照组减少0.9 log(cfu/g)。当臭氧处理时间超过90 min时,杀菌效果无显著变化。在臭氧处理过程中,蒜片中的大蒜素含量、水分含量、蛋白质含量,复水比及色泽均未发生显著性改变。臭氧处理对于脱水蒜片,具有良好的减菌效果。     

2009—2011年北京市西北部城区4类饮用水监测结果分析

目的对北京市西北部城区近3年瓶(桶)装饮用纯净水、饮用天然矿泉水等4类饮用水的监测结果进行统计分析,发现该地区饮用水的安全问题,以便及时消除隐患。方法于2009—2011年对北京市西北部城区的20家单位生产、销售或饮用的瓶(桶)装饮用纯净水、饮用天然矿泉水、饮用净水及生活饮用水,依据相应的卫生或质量标准进行监测检验。结果共检验50件饮用水样品,总体合格率为50.00%,其中饮用天然矿泉水及生活饮用水样品均为合格,瓶(桶)装饮用纯净水样品合格率为36.67%,饮用净水样品均不合格。瓶(桶)装饮用纯净水不合格指标为pH值、电导率、高锰酸钾消耗量、氯化物、菌落总数及霉菌和酵母菌,饮用净水不合格指标为色度、pH值、总硬度、铁、硫酸盐、耗氧量、铅及细菌总数。瓶(桶)装饮用纯净水的pH值超标率为66.67%,且pH测定值最高达到8.48,为国家标准上限值的1.2倍。结论北京市西北部城区近3年瓶(桶)装饮用纯净水及饮用净水检验合格率很低,二者共同的问题为pH值、耗氧量及菌落总数超标。瓶(桶)装饮用纯净水普遍存在pH值超标情况,亟待引起重视。建议加强瓶(桶)装饮用纯净水及饮用净水的主动监测与监督管理。     

兼香型白云边酒不同工艺高温大曲差异性分析

以机械大曲、人工大曲和混合大曲为例,分析其理化指标及微生物数量的差异性。结果表明,混合大曲酒化力和生香力最高,分别达到9.70%和238.74 mg/100 g;机械大曲和人工大曲酯化力差异不大,分别为87.90 mg/g和87.64 mg/g,均高于混合大曲;而机械大曲的液化力和糖化力最高,分别为10.77 U/g和236.40 U/g。传统稀释涂平板法微生物分析结果表明,混合大曲霉菌总数达到1.53×104cfu/g,约为机械大曲和人工大曲的1.5倍;混合大曲酵母菌总数为1.78×105cfu/g,高出机械大曲和人工大曲4~8倍;而机械大曲和人工大曲细菌总数分别为1.73×106cfu/g和1.27×106cfu/g,均高于混合大曲;芽孢杆菌含量最高的是机械大曲,达到1.28×106cfu/g。     

USE OF OZONE TO INACTIVATE MICROORGANISMS ON LETTUCE

When ozone (1.3 mM) was bubbled for 3 min in a mixture of shredded lettuce and water, counts ofmesophilic andpsychrotrophic bacteria decreased 1.4 and 1.8 log₁₀ cfu/g, respectively. Counts of these microorganisms on lettuce, from a different batch, decreased 3.9 and 4.6 log, respectively, during 5 min of ozone treatment. Shredded lettuce was treated with gaseous ozone, or mixed with aqueous solution of ozone (1:20 w/w) with or without bubbles. For effective delivery of ozone, stirring (low and high speed), sonication or stomaching was applied during the ozonation. Washing the lettuce with water only decreased total count on shredded lettuce by 0.74–1.0 log cfu/g. When lettuce in a treatment chamber was flushed with gaseous ozone, the total count decreased 0.85 log cfu/g, but when vacuum was applied before the ozone flush, the total count decreased 0.96 log cfu/g. Bubbling ozone in water-lettuce mixture while sonicating, high-speed stirring, or before stomaching inactivated 1.4, 1.9 and 1.9 log cfu/g, respectively. In conclusion, bubbling gaseous ozone in water is the most effective ozonation method. Efficient ozone delivery to microorganisms on lettuce requires a combination of ozone bubbling and high-speed stir.     

Microbiological safety of bottled mineral water in patients susceptible to infections

We evaluated the microbiological safety of bottled mineral water products commercially available in Japan. Of 10 bottled mineral water products manufactured in Japan, no bacteria or fungi were detected in 9 (90%), but 1 (10%) contained 1.8x10(3) colony-forming units (cfu)/mL. Of 12 bottled mineral water products manufactured in the EU, 11 (91.7%) contained 23-3.5x10(4) cfu/mL. On the other hand, of 5 bottled mineral water products manufactured in North America, 2 (40%) contained 2.3x10(2)-2.5x10(3) cfu/mL. The detected microorganisms were glucose-nonfermentative Gram-negative bacilli such as Brevundimonas vesicularis, Moraxella spp., and Burkholderia cepacia, but Pseudomonas aeruginosa was not detected in any product. For immunocompromised host patients being managed in ultra-clean rooms, the examined bottled mineral water products manufactured in Japan, except 1, were microbiologically safe.     

A survey of the microbiological quality of bottled water sold in the UK and changes occurring during storage.

Eight brands of domestic and imported bottled water were microbiologically analysed within three hours of purchase at a local supermarket. Viable numbers of microorganisms were estimated on Plate Count Agar (PCA) and PCA diluted to quarter and tenth strengths (1/4 PCA and 1/10 PCA) and incubated at temperatures of 10, 15, 25 and 37 degrees C. Plate count agar diluted to 1/4 and 1/10 incubated at 25 degrees C yielded the highest initial counts, up to 10(4) cfu ml(-1). Pseudomonas spp. was the predominant species. After 6 months of storage at room temperature (18-25 degrees C), few quantitative and qualitative differences were found in the microflora.     

瓶装饮用纯净水细菌数量变化规律研究

对瓶装饮用纯净水细菌数量变化规律进行了研究。在某生产厂家采集5加仑和600ml塑料瓶（桶）装纯净水保存于室温。自生产后3h,每24～56h检验菌落总数,至保存35d止。保存过程中,所有600ml瓶装水试样的细菌数量均急剧增加,在5～7d内达到高峰,菌数范围在＜1～1．53×105ml-1之间,之后,生长曲线呈现双峰。同样情况也出现在5加仑桶装成品中。     

桶装纯净水的微生物检测与鉴定

选用成品桶装纯净水为研究对象,成品分别在下线6 h、12 h、24 h、48 h、96 h后进行菌落总数检测,并对其微生物类别进行鉴定,目的是对桶装纯净水中的微生物有针对性地进行预防和控制。结果表明,成品下线6 h后,检测样品时几乎没有微生物的存在,然而随着时间的延长,菌落总数明显的增多。分别对不同的菌落进行分离、纯化并进行鉴别,结果显示有细菌（主要是大肠杆菌）和真菌。     

Efficacy of ozone in killing Listeria monocytogenes on alfalfa seeds and sprouts and effects on sensory quality of sprouts

A study was done to determine the efficacy of aqueous ozone treatment in killing Listeria monocytogenes on inoculated alfalfa seeds and sprouts. Reductions in populations of naturally occurring aerobic microorganisms on sprouts and changes in the sensory quality of sprouts were also determined. The treatment (10 or 20 min) of seeds in water (4 degrees C) containing an initial concentration of 21.8 +/- 0.1 microg/ml of ozone failed to cause a significant (P < or = 0.05) reduction in populations of L. monocytogenes. The continuous sparging of seeds with ozonated water (initial ozone concentration of 21.3 +/- 0.2 microg/ml) for 20 min significantly reduced the population by 1.48 log10 CFU/g. The treatment (2 min) of inoculated alfalfa sprouts with water containing 5.0 +/- 0.5, 9.0 +/- 0.5, or 23.2 +/- 1.6 microg/ml of ozone resulted in significant (P < or = 0.05) reductions of 0.78, 0.81, and 0.91 log10 CFU/g, respectively, compared to populations detected on sprouts treated with water. Treatments (2 min) with up to 23.3 +/- 1.6 microg/ml of ozone did not significantly (P > 0.05) reduce populations of aerobic naturally occurring microorganisms. The continuous sparging of sprouts with ozonated water for 5 to 20 min caused significant reductions in L. monocytogenes and natural microbiota compared to soaking in water (control) but did not enhance the lethality compared to the sprouts not treated with continuous sparging. The treatment of sprouts with ozonated water (20.0 microg/ml) for 5 or 10 min caused a significant deterioration in the sensory quality during subsequent storage at 4 degrees C for 7 to 11 days. Scanning electron microscopy of uninoculated alfalfa seeds and sprouts showed physical damage, fungal and bacterial growth, and biofilm formation that provide evidence of factors contributing to the difficulty of killing microorganisms by treatment with ozone and other sanitizers.     

Temporal variation of microbiological and chemical quality of noncarbonated bottled drinking water sold in Sri Lanka

Use of bottled water in Sri Lanka has increased over the last decade, while new brands of bottled water are often introduced to the market. However, the manufacturers' adherence to bottled water regulations is questionable, raising concerns regarding the quality of bottled water. The objective of the current study was to investigate the microbiological and chemical quality of bottled water in Sri Lanka. Thirty bottled water brands were sampled and their chemical and microbiological parameters were analyzed. Microbiological analysis was carried out within 1 to 3, 3 to 6, 6 to 9, and 9 to 12 mo after the date of manufacture. The results indicated that 63% of brands tested exceeded the levels permitted by the Sri Lanka Standards Institution (SLSI) for presumptive total coliforms (TC) (<10 cfu per 100 mL) whereas 97% brands exceeded the World Health Organization (WHO) permitted level. Thirty percent of brands exceeded the limit for presumptive fecal coliforms (FC) (0 cfu per 100 mL in accordance with WHO permitted levels, SLSI and the Sri Lanka Health Ministry requirement). Eighty percent of brands showed higher heterotrophic plate counts (HPC) which exceeded the WHO guidelines for bottled drinking water. Throughout their shelf life, the counts of TC, FC, and HPC bacteria decreased. Bacteria identified were Klebsiella pneumoniae ssp. pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, and Pasteurella haemolytica, the most frequently being P. aeruginosa. The dominant fungi identified were Aspergillus sp. and Penicillium sp. Inorganic chemical parameters were within permitted levels for all brands except for initial content of ammonia. The results of this study show the need for the bottling industry to be monitored closely by relevant authorities, in order to provide safe bottled drinking water to consumers in Sri Lanka.     

不同条件对糙米发芽过程中微生物数量的影响

为了确定安全食用的发芽糙米生产方法,在不同温度和不同的发芽方法下,对不清洗和定时清洗的糙米进行微生物检测.结果表明,采用浸泡发芽法和密闭气相发芽法时,温度越高.发芽时间越长,细菌总数越多,定时清洗只能适当减少微生物的数量,如密闭气相发芽法,25℃、48h,不定时清洗的样品细菌总数达到2.43×10~8cfu/g,定时清洗的样品细菌总数为1.31 × 10~8cfu/g.而流动水相发芽法的样品细菌总数仅为6.5 × 10~3cfu/g,远低于其他两种发芽方法.因此,相对于传统发芽法,流动水相法是较为安全的发芽方法.     

Sporicidal action of ozone and hydrogen peroxide: a comparative study.

Elimination of contaminating spores on packaging materials and food-contact surfaces remains a challenge to the food industry. Hydrogen peroxide and chlorine are the most commonly used sanitizers to eliminate these contaminants, and ozone was recommended recently as an alternative. Hence, we compared the sporicidal action of ozone and hydrogen peroxide against selected foodborne spores of Bacillus spp. Under identical treatment conditions, 11 microg/ml aqueous ozone decreased spore counts by 1.3 to 6.1 log10 cfu/ml depending upon the bacterial species tested. Hydrogen peroxide (10%, w/w), produced only 0.32 to 1.6 log10 cfu/ml reductions in spore counts. Thus, hydrogen peroxide, at approximately 10,000-fold higher concentration, was less effective than ozone against Bacillus spores. Resistance of spores to ozone was highest for Bacillus stearothermophilus and lowest for B. cereus. Therefore, spores of B. stearothermophilus are suitable for testing the efficacy of sanitization by ozone. Electron microscopic study of ozone-treated B. subtilis spores suggests the outer spore coat layers as a probable site of action of ozone.