奶粉中阪崎肠杆菌的风险评估

阪崎肠杆菌能引起脑膜炎、NEC和菌血症等，约2．5％～14％婴儿配方奶粉含有阪崎肠杆菌，0％～12％的普通奶粉含有阪崎肠杆菌，含量从0．36-66．0cfu／100g。婴幼儿奶粉中的阪崎肠杆菌问题已受到了全世界的普遍关注。本文基于大量研究和调查数据，从奶粉中阪崎肠杆菌的危害识别、奶粉中阪崎肠杆菌的暴露评估、奶粉中阪崎肠杆菌危害特性以及阪崎肠杆菌的检测方法等方面客观地对奶粉中阪崎肠杆菌进行风险评估，并对降低我国婴儿配方奶粉中阪崎肠杆菌风险提出建议。     

奶粉中阪崎肠杆菌的分离与鉴定

目的了解某地区婴儿配方奶粉中阪崎肠杆菌的污染情况,为我国制定婴儿配方奶粉中阪崎肠杆菌的限量标准及为政府加强对婴儿配方奶粉的管理提供科学依据。方法常规生理生化鉴定法和实时荧光PCR法。结果检出2株阪崎肠杆菌。结论我国市售的婴儿配方奶粉中存在少量的阪崎肠杆菌污染。     

中国安徽阜阳劣质婴儿配方粉中阪崎肠杆菌的污染

2004年中国安徽阜阳劣质婴儿配方粉事件引起了我国政府的高度重视.为了调查婴儿配方粉中阪崎肠杆菌的污染状况,根据美国FDA和加拿大实验室的方法,建立了婴儿配方粉中阪崎肠杆菌的分离鉴定技术.从87份阜阳劣质奶粉样品中检测到11份阪崎肠杆菌阳性样品,污染阳性率为12.6%.用API 20E和Qualicon BAX(R)系统鉴定了11株阪崎肠杆菌.这是国内首次从婴儿配方粉中分离到阪崎肠杆菌菌株.     

柳江县市售国产婴幼儿配方粉中阪崎肠杆菌污染监测分析

目的 了解市售国产婴幼儿配方粉中阪崎肠杆菌污染状况,为消费预警提供科学依据。方法 分别按2011、2012年版国家食源性致病菌监测工作手册对市场上11家国内生产的32份婴幼儿配方粉进行检测。结果 32份样品检出2株阪崎肠杆菌,检出率为6.25%。其中婴幼儿配方奶粉中阪崎肠杆菌检出率4.35%(1/23);婴幼儿谷物食品中阪崎肠杆菌检出率11.11%(1/9)。结论 柳江县市售部分婴幼儿配方粉中存在阪崎肠杆菌污染,食用安全隐患不容忽视,应加强监测力度,预防和控制阪崎肠杆菌引起的食物中毒事件发生。     

配方奶粉生产过程中阪崎肠杆菌的风险与控制

阪崎肠杆菌是20世纪发现的一种对婴幼儿具有严重健康威胁的致病微生物,在婴幼儿配方奶粉的原料和生产过程中都有污染阪崎肠杆菌的风险。准确对配方奶粉生产过程中阪崎肠杆菌的污染风险进行评价,并相应制定科学有效的风险控制措施,对于降低风险、提高产品品质、保障食品安全具有重要意义。本文综述了配方奶粉生产过程中阪崎肠杆菌的存活规律、配方奶粉原料中可能存在的被阪崎肠杆菌污染的风险,以及通过环境、空气、设备以及制度操作等方面对阪崎肠杆菌风险进行控制的各种措施。     

应用VITEK全自动微生物鉴定系统检测婴儿配方奶粉中阪崎肠杆菌

基于对婴儿配方奶粉中微生物安全性问题的关注，本实验对婴儿配方奶粉中阪崎肠杆菌的检测方法进行了初步研究。应用VITEK32自动微生物鉴定系统对人工污染的婴儿配方奶粉中的阪崎肠杆菌进行检测，获得与美国食品药品管理局（FDA）推荐的API 20E生化鉴定方法一致的结果。     

奶粉中阪崎肠杆菌的污染及快速检测方法的研究

目的：了解福建省市售婴幼儿配方奶粉中阪崎肠杆菌的污染状况、污染途径并寻找快速准确的检测方法。方法：应用分离鉴定、PCR 和荧光PCR 等方法检测,分离鉴定采用阪崎肠杆菌显色培养基和全自动微生物生化仪。结果：阪崎肠杆菌在192 份市售婴幼儿配方奶粉中的检出率为1.56%,在60 份原料奶粉中的检出率为13.33%,30 份生产车间环境样本均未检出。结论：福建省市售婴幼儿配方奶粉中存在阪崎肠杆菌的安全隐患,某工厂奶粉中阪崎肠杆菌的污染主要来自原料奶粉。荧光PCR 和显色培养基可用于阪崎肠杆菌的快速筛选和分离。     

阪崎肠杆菌的生物学特性及其在婴幼儿配方奶粉中的预测模型

研究阪崎肠杆菌的生长特性,考察不同温度、NaCl含量、pH值条件下阪崎肠杆菌在脑-心浸萃液态培养基中的生长情况。为建立婴幼儿配方奶粉中阪崎肠杆菌的生长模型,将阪崎肠杆菌接种到婴幼儿配方奶粉中,用4个一级生长模型结合美国农业部东部地区研究中心开发的IPMP2013软件,拟合阪崎肠杆菌在37℃的生长情况。结果表明:阪崎肠杆菌的最适生长条件:温度35~40℃,NaCl含量1%~3%,pH 5~8。温度、NaCl含量、pH值对阪崎肠杆菌存在显著性影响。Huang模型比Baranyi模型、Gompertz模型和Three-Phase Linear模型更适合拟合婴幼儿配方奶粉中阪崎肠杆菌生长曲线。     

味全奶粉被检测出含致病菌

目前,国家质检总局公布了去年8月至11月进境的852批不合格食品、化妆品名单。其中,味全食品的三类配方奶粉被检验出含有致病菌阪崎肠杆菌。去年10月17日,产自台湾的9,624吨配方奶粉从香港进境时被检验出阪崎肠杆菌超标,进口商为深圳市恒利安贸易有限公司。不合格奶粉包括味全婴儿配方奶粉、味全幼儿成长配方奶粉和味全较大婴儿配方奶粉。     

3种方法检测婴幼儿配方奶粉中的阪崎肠杆菌

目的对市售婴幼儿配方奶粉中阪崎肠杆菌检测方法进行研究。方法分别用常规培养鉴定方法、常规PCR方法和实时荧光PCR方法对32份奶粉样品进行阪崎肠杆菌分离鉴定。结果32份样品中检出2株阳性株，阳性率为6．25％，3种鉴定方法结果相符。结论联合使用多种鉴定方法可提高阪崎肠杆菌检测的可靠性。     

Enterobacter sakazakii: a coliform of increased concern to infant health

The first cases of neonatal meningitis believed to have been caused by Enterobacter sakazakii were reported in 1961. Prompted by several subsequent outbreaks of E. sakazakii infections in neonates and an increasing number of neonates in intensive care units being fed rehydrated powdered infant formula, considered to be a source of the pathogen, public health authorities and researchers are exploring ways to eliminate the bacterium or control its growth in dry infant formula, processing environments and formula preparation areas in hospitals. Reviewed here are advances in taxonomy and classification of E. sakazakii, methods of detecting, isolating and typing the bacterium, antibiotic resistance, clinical etiology and pathogenicity. Outbreaks of E. sakazakii infections in neonates and adults are summarized. Reports on the presence of E. sakazakii in clinical settings, the environment and foods and food processing facilities are reviewed. Tolerance of the pathogen to environmental stresses, its behavior in powdered and rehydrated infant formulae and hazard analysis and risk management are discussed. Research needs are presented.     

Characterization of a collection of Enterobacter sakazakii isolates from environmental and food sources

Enterobacter sakazakii has emerged as a rare cause of neonatal meningitis, septicemia and enterocolitis. Contaminated infant milk formula (IMF) has been identified as one infection route. A small number of clinical outbreaks have been epidemiologically linked to IMF contaminated post-pasteurization during manufacture and/or mishandled when reconstituted. Currently no agreed standardized typing protocol has been developed to trace E. sakazakii. The objectives of this study were to apply biochemical and genetic methods to characterize 51 environmental and food E. sakazakii isolates and 6 E. sakazakii type strains. Isolates were presumptively identified using biochemical profiles based on API 20E and ID32E methods and by culture on differential selective Druggan Forsythe Iversen (DFI) agar. Identification was subsequently confirmed by real time polymerase chain reaction (PCR). All but one of the isolates was identified as E. sakazakii by biochemical profiling. One isolate was identified as Escherichia vulneris by ID 32E and as Pantoea agglomerans by API 20E. All isolates produced green/blue colonies on DFI medium characteristic of this organism. Real time PCR could differentiate between E. sakazakii, Enterobacter spp. and other Enterobacteriacae. Analysis of RAPD banding patterns revealed 3 major clusters of E. sakazakii. There was a large degree of diversity noted amongst the remaining isolates. Our findings indicate that RAPD may be applied as a useful and reliable tool for direct comparison of E. sakazakii isolates providing traceability through the infant formula food chain.     

乳粉中阪琦肠杆菌的PCR检测

针对我国食品进出口和生产卫生的需要,使用以16 S rRNA基因为靶序列设计合成了一对可扩增282 bp的目的片段的引物,建立了检测阪琦肠杆菌的PCR方法.结果表明,阪琦肠杆菌PCR产物有282 bp的特异性片段,而金黄色葡萄球菌无此目的条带,证实该引物具有特异性.该方法快速、可靠、灵敏,特异性强,可用于食品中阪琦肠杆菌的检测.     

DETECTION AND DISCRIMINATION OF ENTEROBACTER SAKAZAKII (CRONOBACTER SPP.) BY MID-INFRARED SPECTROSCOPY AND MULTIVARIATE STATISTICAL ANALYSES

Enterobacter sakazakii can cause rare but life-threatening diseases such as meningitis in infants and neonates. Fourier transform infrared (FT-IR) spectroscopy was used to detect and discriminate between eight E. sakazakii strains, two Enterobacter cloacae strains, three Escherichia coli strains and two Klebsiella pneumoniae strains. FT-IR vibrational combination bands reflect subtle compositional differences in the cell membranes of E. sakazakii strains, especially in the region between 1,200 and 900 cm ^{− 1} which contains absorption bands from carbohydrates. Two multivariate statistical analyses including principal component analysis (PCA) and soft independent modeling of class analogy (SIMCA) were used for data analysis. E. sakazakii strains were clearly distinguishable from the other strains by PCA. Based upon SIMCA analysis, 90% of E. sakazakii, 88% of E. cloacae, 91% of E. coli and 91% of K. pneumoniae samples were correctly classified, suggesting that this technique could be used to detect E. sakazakii strains rapidly and accurately.

PRACTICAL APPLICATIONS

Fourier transform infrared (FT-IR) coupled with multivariate statistical analyses can be used to detect, discriminate and identify Enterobacter sakazakii strains that have been implicated in food safety incidents caused by contaminated infant formula. Compared with traditional microbiological plating methods, this new approach of using FT-IR could be an alternative means for rapid and accurate detection of bacterial samples that are important in agricultural, food and medical areas.     

Microbiological, epidemiological, and food safety aspects of Enterobacter sakazakii

Enterobacter sakazakii is considered to be an opportunistic pathogen and has been implicated in foodborne diseases causing meningitis or enteritis, especially in neonates and infants. The U.S FoodNet 2002 survey rate of invasive infections with this organism in infants under 1 year of age was 1 per 100,000 infants. Severity of the disease is a matter of concern. In a recent study on the occurrence of E. sakazakii in production environments from food (milk powder, chocolate, cereal, potato, and pasta) factories and households, this organism was isolated with varying frequency from nearly all environments examined, strongly indicating that it is widespread. Stationary phase E. sakazakii cells are remarkably resistant to osmotic and drying stresses compared with other species of the Enterobacteriacae. In this article, we review the literature on this organism with special respect to the information relevant for food safety.     

Inactivation of Enterobacter sakazakii in reconstituted infant formula by monocaprylin

Enterobacter sakazakii is an emerging pathogen that causes meningitis, bacteremia, sepsis, and necrotizing enterocolitis in neonates and children, with a mortality rate of 14%. Epidemiological studies have implicated dried infant formula as the principal source of the pathogen. Caprylic acid is a natural eight-carbon fatty acid present in breast milk and bovine milk and is approved as generally recognizable as safe by the U.S. Food and Drug Administration. The objective of this study was to determine the antibacterial effect of monocaprylin (monoglyceride ester of caprylic acid) on E. sakazakii in reconstituted infant formula. A five-strain mixture of E. sakazakii was inoculated into 10-ml samples of reconstituted infant formula (at 6.0 log CFU/ml) followed by 0, 25, or 50 mM (1%) monocaprylin. The samples were incubated at 37 or 23 degrees C for 0, 1, 6, and 24 h and at 8 or 4 degrees C for 0, 6, 24, and 48 h, and the surviving populations of E. sakazakii at each sampling time were counted. The treatments containing monocaprylin significantly reduced the population of E. sakazakii (P < 0.05) compared with the controls. Monocaprylin (50 mM) reduced the pathogen by >5 log CFU/ml by 1 h of incubation at 37 or 23 degrees C and by 24 h of incubation at 8 or 4 degrees C. Results indicate that monocaprylin could potentially be used to inactivate E. sakazakii in reconstituted infant formula; however, sensory studies are warranted before its use can be recommended.     

Enterobacter sakazakii: biological properties and significance in dried infant milk formula (IMF) powder†

Enterobacter sakazakii is an emerging opportunistic pathogen associated with rare but life‐threatening cases of meningitis, necrotizing enterocolitis and sepsis in premature infants. The bacterium has been isolated at low levels from dried infant milk formulas and is a cause of concern to all manufacturers. The threat posed by E. sakazakii is further compounded by a paucity of knowledge in key areas, specifically its ecology and physiology. This organism now represents a serious challenge to all those involved in the manufacture of infant formula products.     

乳品中坂崎肠杆菌污染情况的调查

<正>坂崎肠杆菌为革兰氏阴性杆菌,是肠杆菌科、肠杆菌属的一个种,由其引发的婴儿、新生儿脑膜炎、败血症和坏死性小肠结肠炎散发和爆发的病例在世界范围内多有报道,致死的病例可高达40%-80%。从调查病例的分析中,婴儿暖     

SENSITIVE AND RAPID DETECTION OF ENTEROBACTER SAKAZAKII IN INFANT FORMULA BY LOOP-MEDIATED ISOTHERMAL AMPLIFICATION METHOD

Enterobacter sakazakii is an emergent pathogen associated with ingestion of infant formula milk and was defined in category "A" of the hazard identification by FAO and WHO on microorganisms, which is based on the strength of evidence of a causal association between their presence in powdered infant formula and illness in infants. In this study, a loop-mediated isothermal amplification (LAMP) method has been developed for the detection of E. sakazakii in infant formula. The assay detected the species-specific DNA sequence of the 16S-23S rRNA internal transcribed spacer. The sensitivity of the detection is 1.2 cfu per 100 g infant formula with the selective enrichment. As the amplification is made under isothermal conditions, only a water bath or heating block is needed to maintain the required temperature. Thus, the method will be easily generalized and popularized in the future.

PRACTICAL APPLICATIONS

Enterobacter sakazakii is an emerging opportunistic pathogen associated with meningitis, bacteria and necrotizing enterocolitis in neonates. Powdered infant formulae have been implicated as the source of infection in neonatal meningitis. Thus, in order to minimize the hazard caused by E. sakazakii , it is of utmost importance to develop a rapid, sensitive and simple method for the early detection of this bacterium in infant formula.
In our study, the E. sakazakii was detected sensitively and rapidly in the infant formula by the loop-mediated isothermal amplification (LAMP) assay. LAMP is easy to perform once the appropriate primers are prepared. The LAMP method will be a simple and rapid method for the scene detection of E. sakazakii as only four primers, a Bst polymerase and a regular laboratory bath are needed.     

Thermal inactivation of Enterobacter sakazakii in rehydrated infant formula

The presence of low levels of Enterobacter sakazakii in dried infant formula have been linked to outbreaks of meningitis, septicemia, and necrotizing enterocolitis in neonates, particularly those who are premature or immunocompromised. In the current study, the ability of 12 strains of E. sakazakii to survive heating in rehydrated infant formula was determined at 58 degrees C with a submerged coil apparatus. The observed D58-values ranged from 30.5 to 591.9 s, with the strains appearing to fall into two distinct heat resistance phenotypes. The z-value of the most heat-resistant strain was 5.6 degrees C. When dried infant formula containing this strain was rehydrated with water preequilibrated to various temperatures, a more than 4-log reduction in E. sakazakii levels was achieved by preparing the formula with water at 70 degrees C or greater.