发光细菌法在食品安全性检测中的应用

食品安全性是当前全社会普遍关注的热点问题。其中，监督检测手段与方法的研究是该领域一个重要的研究方向．作者阐述了发光细菌检测法在污染物快速检测中的应用、通过对发光细菌法在农药残留、重金属毒性与生物毒素等方面的检测研究表明，作为一种速度快、灵敏度高、成本低廉的生物毒性监测方法，发光细菌法将在食品安全快速检测领域中有着广泛的应用前景．     

Detection of fresh-cut produce processing residues on food contact surface materials using hyperspectral imaging

To reduce the risk of foodborne-illness, produce processors currently clean and sanitize food contact surfaces daily before production starts. Current methods to verify the efficacy of cleaning procedures include visual inspection and direct surface sampling using ATP bioluminescence assays and culturing methods. To assess the possibility of augmenting these existing verification methods, this study investigated the potential to use imaging techniques to detect fresh-cut produce residues. A laboratory hyperspectral system was used to image produce residues obtained from a commercial processing plant, cantaloupe and honeydew residues generated in-house, and selected cleaning and sanitizing agents. Test materials were dispensed onto stainless steel and high density polyethylene coupons. The coupons were selected to represent common surfaces used in production facilities. Analysis of VIS/NIR hyperspectral reflectance and fluorescence images showed that the cleaning and sanitizing agents were essentially undetectable; thus, demonstrating that presence of these substances would not result in false-positives. In contrast, produce residues in microgram quantities showed fluorescence peaks encompassing the regions from 480 to 560 nm and from 670 to 690 nm. However, auto-fluorescence responses of high density polyethylene at shorter wavelengths were found to obscure the 480 to 560 nm peaks for some residues. These results suggest that fluorescence imaging techniques can be used to enhance surface hygiene inspection in produce processing plants and, given the immediate availability of imaging results, to help optimize routine cleaning procedures.     

Role of Disinfection in Food Industry

In industrialized countries, the epidemiology of infec- tious diseases with indirect transmission through water and foodstuffs has undergone considerable changes over the past decades with the almost total disappearance of some traditional pathogen microo…     

Control of Salmonella in food related environments by chemical disinfection

Salmonella may be transferred to food through cross-contamination during processing and preparation. To minimise the risk of cross-contamination, proper cleaning and disinfection is essential for the food industry. Recently, disinfection of areas for preparation and storage of food has also gained increased popularity in households. There is a range of disinfectants available with different properties and usage areas, and care must be taken to choose the proper disinfectant for the specific application.There are many methods for testing the antimicrobial effect of disinfectants. To evaluate whether a disinfectant will be effective in practical settings, the test method should model real-life situations. Most disinfectants are effective against Salmonella at recommended user concentration in suspension tests. However, a number of factors may reduce the biocidal effect of disinfectants under practical conditions. This include properties of the surface to be disinfected, presence of soiling on the surface, the physiological state of the bacteria exposed to disinfection, including bacteria embedded in biofilms, and the effects of other stresses (e.g. desiccation, starvation and temperature).Here we review the effects of disinfectants used in food related areas in industries and in households against Salmonella. A general overview is given for disinfectants in use and methods used to evaluate effects. Effects of disinfectants against Salmonella in suspension and on surfaces, including biofilms, are presented and compared. Novel control strategies such as use of electrolysed water, antimicrobial surfaces, and anti-biofilm compounds are also covered. Finally, we review the ability of Salmonella to gain reduced susceptibility to disinfectants through adaptation and other physiological responses like biofilm formation.     

Adenosine triphosphate bioluminescence for hygiene testing of rubber liners and tubes on dairy farms

Prevention of biofilm formation in milking equipment is important to ensure good hygiene quality of raw milk. Key factors to achieving good results are a successful cleaning procedure and a method to check the cleanliness of milking equipment surfaces. Adenosine triphosphate bioluminescence is a fast and easy method for investigating bacterial contamination of surfaces. However, previous studies on the potential of ATP bioluminescence to assess the hygiene status of milking equipment have been hampered by lack of a validated test procedure. The aim of this work was therefore to establish a test procedure for assessing the cleanliness of milking equipment using ATP bioluminescence, and apply the method on-farm to study the hygiene status of aging rubber material in milking equipment. In developing the test procedure, the effects of sampling location in tubes and liners, sampling of dry versus wet barrels, milking point in the parlor, and acid or alkali detergent on ATP values were investigated. The results showed that, to obtain reproducible results, replicate sampling from the same milking points in the parlor is important. For milk tubes, samples should preferably be taken from the milk meter side, for liners on the inside of the barrel. For best results, sampling should be performed after use of alkali detergent. No beneficial effect was observed of sampling dry liner barrels, so sampling in the standardized test procedure is performed directly after cleaning. The standardized test procedure was used on 3 different commercial farms and sampling was initiated after replacement of old rubber parts. On one of the farms, additional sampling was performed to evaluate total bacteria count and determine the association with ATP level. The results suggest that, provided an efficient cleaning procedure is used, the hygiene quality of milking equipment can be maintained during the recommended lifetime of the rubberware. However, due to occasional variation in cleaning efficiency between milking points and liner barrels, random sampling on single occasions can lead to incorrect conclusions. Replicate sampling over time is therefore important for correct interpretation of ATP bioluminescence data. If ATP levels are very high, complementary sampling for total bacteria count should be used to verify that the level is due to bacterial contamination, and not other organic ATP-contributing material (e.g., milk residues).     

两种副溶血性弧菌检测方法的比对

目的比较国家标准中的定性检测法与快速检测法中的普通PCR法在检测食源性副溶血性弧菌上的区别与优劣,为今后针对副溶血性弧菌的检测方法的改进依据及应对突发食品安全事件时快速检测提供参考。方法采用GB4789.7-2013《食品安全国家标准食品微生物学检验副溶血性弧菌检验》与SN/T1869-2007《食品中多种致病菌快速检测方法 PCR法》对经阳性菌株污染的市售墨鱼干样品进行副溶血性弧菌的检测,并对2种方法进行对比。结果 2种方法在针对食源性副溶血性弧菌的检验上的比对结果均为检出。在实验耗时方面,国家标准法确认检出阳性需耗时4 d,快速检测法仅需耗时26 h。结论国家标准中的定性检测法与快速检测方法均能检出副溶血性弧菌,国标法在应对日常检验上标准且能够广泛应用,快速检测方法在快速、准确地应对食品安全突发事件方面具有优势。     

食品中菌落总数的国标法测定注意事项及微生物快速测试卡法检测

综述了食品中菌落总数的国标法检测注意事项,并介绍了微生物快速测试卡在菌落总数测试中的应用,指出测试片法将成为未来微生物检测中有前景的手段之一。     

Potentiation of the lethal effect of peroxygen on Bacillus cereus spores by alkali and enzyme wash

Bacillus cereus present in pipes and heat-exchangers represents a potential quality problem for dairy industry. The peroxygen-containing disinfectants investigated had only negligible sporicidal effect when applied at the recommended in-use temperature and concentration. However, cleaning agents used before disinfection potentiated their lethal activity. Pre-exposure of B. cereus spores to 1% sodium hydroxide at temperatures over 40 degrees C increased the sporicidal effect of the peroxygen-containing disinfectant. The effect was dependent on the alkali concentration and the temperature. Also, a significant potentiating activity of an enzyme-based cleaning agent was obtained, but the effect was smaller than for alkali treatment. The results indicated that disinfectants based on peroxygen can be used to eliminate B. cereus spores at non-corrosive temperatures and concentrations if the surfaces are cleaned with alkali or enzyme-based disinfectants prior to disinfection.     

不同清洗方法对草莓中农药残留清洗效果的研究

目的考察不同清洗方法对草莓中农药残留的清洗效果,确定减少草莓中农药残留的最优清洗方法。方法采用正交设计的方法,用最少的实验次数,考察清洗溶剂、清洗方式、清洗时间、清洗温度等因素对清洗效果的影响,每个因素下设有不同的影响水平,充分考虑各个因素下不同水平对清洗结果的影响,共设计27组不同的清洗方法。采用高效液相色谱-串联质谱法同时测定8种农药的残留量,比较清洗前后的农药残留量作为清洗效果的评价指标。结果以2%碳酸氢钠水溶液为清洗溶剂,在40℃的条件下超声10 min取得的清洗效果最好,能将5种不同的农药残留量降低30%以上。结论该方法设计科学,结果可靠,容易操作,可用于草莓日常清洗的方法,为草莓的食用安全提供了一定的保障。     

Microbiological and chemical analyses of stainless steel and ceramics subjected to repeated soiling and cleaning treatments

Stainless steel and ceramic surfaces were subjected to repeated soiling and cleaning procedures, using a milk powder soil inoculated with Pseudomonas aeruginosa and Staphylococcus aureus, followed by spraying with water with or without 0.1% (vol/vol) nonionic detergent. Test surfaces were removed after 1, 5, 10, and 20 soiling-cleaning cycles and were analyzed for attached microorganisms (total viable count of bacteria removed by swabbing and percentage of coverage of cells plus soil stained with acridine orange). Surfaces were additionally examined using a range of analytical techniques: X-ray photoelectron spectroscopy (XPS), dynamic and imaging secondary ion mass spectroscopy (SIMS), and time-of-flight SIMS. Both microbiological and chemical analyses revealed an accumulation of material over the cycles to a maximum level. Surfaces were conditioned rapidly to saturation with organic material within one cycle (XPS), whereas fouling by microorganisms was less rapid (five cycles). Cleaning with detergent tended to retard the cumulative fouling process when compared with spray cleaning using water alone. The methods described provide a more realistic scenario for testing the cleanability of surfaces routinely found in food processing locations and for screening novel cleaning regimens and/or surface materials. The analytical techniques provide additional information on the kinetics of soiling, which complement the more familiar microbiological methods.     

Screening of antimicrobial activities of disinfectants and cleaning agents against foodborne spoilage microbes

 The antimicrobial activities of six disinfectants and cleaning agents against five food and brewery spoilage microbes were studied using the 5-5-5 suspension and a surface test simulating surface disinfection in actual use. The tests were carried out using the lowest recommended concentrations. The surface test was performed both with and without organic soil for various exposure times. In the suspension test, almost all the disinfectant and cleaning agents had adequate antimicrobial activity, except against Bacillus spores. The peroxide-based disinfectant and the isopropanol-based cleaning agent were both ineffective against Saccharomyces cerevisiae. In the surface test without soil the hypochlorite-based disinfectant was effective after an exposure of 10 min against all the microbes tested. The isopropanol-based cleaning agent was effective against all the vegetative cells tested. In the presence of soil, hypochlorite was effective against Listeria monocytogenes and Pseudomonas aeruginosa. In the test performed the lubricant which contained disinfectant had no antimicrobial activity against the surface-attached contaminants tested. P. aeruginosa was the most sensitive test organism and the Bacillus spores were the most resistant towards the agents tested. Received: 30 June 1998     

食品加工用水微生物检测的重要性

食品加工业是用水型工业之一,水质的优劣对食品安全至关重要,对加工用水进行安全卫生控制是生产过程控制的重要环节。微生物污染是食品加工用水最主要的安全隐患之一,我国食品加工用水微生物污染风险高、概率大,每年因食品加工用水微生物污染导致的产品质量问题不在少数,给企业造成了巨大的经济损失。食品加工企业对加工用水的质量控制必不可少,尤其是加工用水的微生物检测能力会影响最终产品的安全性。企业应打破只重视原料、过程产品和最终产品微生物检测的老思路,注意监控加工用水的微生物污染情况。参加水质微生物能力验证能够加强企业实验室对生产加工用水的自我检测能力,确保检测结果的准确性和认可性,对提高产品质量和品质有促进作用。     

超声波与过氧乙酸的杀菌机制及在食品保鲜中的应用进展

果蔬、肉类、水产品等食品中微生物的生长繁殖会引起食品腐败变质,引发食品安全问题,造成经济损失与食物浪费。超声波作为一种绿色环保的非热加工技术,可利用空化效应消灭微生物。过氧乙酸是一种环境友好型的清洗剂,可作为含氯清洗剂的良好替代物。超声波与过氧乙酸均为环境友好型保鲜方式,二者联合使用在食品保鲜中具有巨大的应用潜力。本文就超声波、过氧乙酸单独使用或者二者联合处理的杀菌机制、对微生物生长的抑制作用、及在食品保鲜中的应用进行综述,并展望了未来的发展趋势,以期为新型绿色环保保鲜技术的创建与应用提供参考。     

食品污染物残留的快速检测技术应用综述及展望

近年来,食品安全问题层出不穷,食品安全问题正受到人们前所未有的关注。食品中的有害物质严重威胁人类的身体健康,对其含量进行快速准确分析具有重要意义。快速检测技术比通常的检测技术具有更快的检测速度,且装置便携、易于实现在线现场检测,在食品安全分析中发挥了重要作用;本文简单介绍了快速检测技术在食品污染物残留检测中的运用,包括检测食品中的农药残留、兽药及饲料添加剂残留、重金属残留、生物性污染物残留等,对检测方法的优点和不足做了透彻的分析,并展望其发展方向,以期为进一步开展食品安全快速分析研究提供参考。     

Rapid and quantitative detection of the microbial spoilage of muscle foods: current status and future trends

The requirement for real-time monitoring in the modern and highly automated food processing environment has stimulated research into rapid microbiological testing. This review will concentrate on the search for a rapid detection system for the microbial spoilage of meats that has been ongoing since at least the 1970s. The metabolic processes and bacteria involved within the microbial spoilage of muscle foods will be outlined prior to a detailed overview of the current methods employed in the industry to quantify levels of spoilage organisms. Despite these detailed microbiological studies there is still a requirement within the food industry for new techniques which would ideally be accurate, non-destructive and give answers in real-time and a range of novel analytical technologies which are currently being developed for the rapid assessment of microbial spoilage in muscle foods will be examined.     

BACTERICIDAL EFFICIENCIES OF COMMERCIAL DISINFECTANTS AGAINST LISTERIA MONOCYTOGENES ON SURFACES

The efficiencies of potassium persulphate, isopropanol, hydrogen peroxide and peracetic acid, quaternary ammonium compound, hypochlorite, sodium dichloroisocyanurate, ethanol and phenol derivatives, tertiary alkylamines and dimethyl alamine betaine-based disinfectants and a hypochlorite-based disinfecting cleaning agent were evaluated against eight Listeria monocytogenes strains representing three different ribotypes. All the disinfectants were effective in a suspension test with an exposure time of 30 s at the lowest concentrations recommended by the manufacturer. The efficiencies on surfaces were reduced. However, on clean surfaces all the agents were considered effective when the exposure time was 5 min and the concentration was the average recommended by the manufacturer. Five of nine disinfectants and the disinfecting cleaning agent were considered effective in soiled conditions in the surface test. The most efficient agent was isopropanol-based and the least effective was the disinfectant containing tertiary alkylamine and dimethyl alamine betaine. Differences in bactericidal efficiencies of disinfectants against different L. monocytogenes strains on meat soiled surfaces were found.     

Use of a portable hyperspectral imaging system for monitoring the efficacy of sanitation procedures in produce processing plants

Cleaning and sanitation of production surfaces and equipment plays a critical role in lowering the risk of food borne illness associated with consumption of fresh-cut produce. Visual observation and sampling methods including ATP tests and cell culturing are commonly used to monitor the effectiveness of the cleaning procedures. This study tested the ability of a hand-held VIS hyperspectral imaging system to augment current monitoring methods. Multiple visits were made to two commercial fresh-cut processing facilities. Fluorescence-based detection and automated cycling among three wavelengths, 475, 520, and 675 nm, proved best for detecting a range of anomalies. Numerous deficiencies in existing cleaning protocols were identified. Plant personnel were able to devise changes in the protocols that eliminated most of the detected problems without increasing the net expenditure for cleaning efforts. In addition, imaging identified sites where ATP test results were higher when compared to results for adjacent areas.     

食品中单增李斯特菌PCR-NALF检测方法

建立了一种快速检测单增李斯特菌的聚合酶链式反应-核酸层析(PCR-NALF)方法,该方法通过一对标记生物素和地高辛的引物,对提取自样品中的DNA进行扩增,然后用包被亲和素和抗地高辛抗体的层析试纸条对扩增产物进行检测,并通过肉眼可见的红色条带进行结果判读,从而替代电泳实现便捷检测。在特异性试验中,其他李斯特菌和常见致病菌均呈现阴性反应,与电泳结果一致。与传统微生物检测法(GB/T 4789.30-2008)相比无显著性差异(χ~2=0,P>0.05)。     

农药残留加工因子及其在膳食暴露评估中的应用

从初级农产品到入口的食品通常需要各种加工处理,而加工过程会影响食品中的农药残留水平,从而影响来源于初级农产品检测数据的风险评估结果的准确性,因此在风险评估模型中纳入农药残留加工因子有助于真实反映农药残留膳食暴露风险。本文以常用的食品加工技术如清洗、去皮、烹调、榨汁、杀菌及其他相关技术为出发点,综述了典型的加工方式对食品中农药残留的影响以及目前相应的加工因子在农药残留暴露评估中的应用情况,为掌握食品中农药在加工过程中的残留动态、改进食品加工技术提供参考,也为农药残留膳食暴露评估提供依据,进而真实反映人群中农药残留的暴露风险。     

A Pilot Study for Identification of <Emphasis Type="Italic">Salmonella</Emphasis> in Food Processing Plants by Real-Time PCR Screening

Salmonella remains a major public health concern worldwide. Microbiological methods are the gold standard for Salmonella detection. These methods are highly specific, but their sensitivity is variable. Moreover, they are lengthy, labour intensive and not always consistent with the speed of food manufacturing processes. Thus, in the food industry, there is the need for more rapid, sensitive and accurate detection methods. The purpose of this study is to describe a Salmonella-monitoring scheme in different food processing plants based on a screening approach by a commercial real-time polymerase chain reaction (PCR) kit and subsequent confirmation of positive molecular results by the reference microbiological method. This scheme was tested on a total of 4,693 samples, 90 of which were positive with the real-time PCR screening; 52 of the positive samples were eventually confirmed by the microbiological method. The real-time PCR kit was tested in comparison to the microbiological method in order to evaluate its performances and drawbacks. The comparison between cycle threshold (Ct) values of real-time PCR and the microbiological results (Wilcoxon rank sum test) showed a statistically significant difference between the Ct values of bacteriological positive and bacteriological negative samples (p value, <0.05). Furthermore, receiver operating characteristic curve analysis was used to identify the Ct value ensuring the lowest level of misclassification between Salmonella-positive and negative samples. The present study confirms that the real-time PCR kit tested could be used as a screening tool, leading to a rapid and sensitive identification of Salmonella and confining bacteriological confirmation to samples previously identified as positive.