Karlshøj K, Nielsen P V, Larsen T O
Center for Microbial Biotechnology, BioCentrum-DTU, Building 221, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
J Food Sci. 2007 Aug;72(6):M187-92. doi: 10.1111/j.1750-3841.2007.00399.x.
In this work the potential of electronic nose analysis for differentiation of closely related fungi has been described. A total of 20 isolates of the cheese-associated species Geotrichum candidum, Penicillium camemberti, P. nordicum, and P. roqueforti and its closely related species P. paneum, P. carneum as well as the noncheese-associated P. expansum have been investigated by electronic nose, GC-MS, and LC-MS analysis. The isolates were inoculated on yeast extract sucrose agar in 20-mL headspace flasks and electronic nose analysis was performed daily for a 7-d period. To assess which volatile metabolites the electronic nose potentially responded to, volatile metabolites were collected by diffusive sampling overnight onto tubes containing Tenax TA, between the 7th and 8th day of incubation. Volatiles were analyzed by gas chromatography coupled to mass spectrometry and the results indicated that mainly alcohols (ethanol, 2-methyl-1-propanol, and 3-methyl-1-butanol) and ketones (acetone, 2-butanone, and 2-pentanone) were produced at this stage. The volatile metabolite profile proved to be species specific. Nonvolatile metabolites were collected on the 8th day of incubation and mycotoxin analysis was performed by high pressure liquid chromatography coupled to a diode array detector and a time of flight mass spectrometer. Several mycotoxins were detected in samples from the species P. nordicum, P. roqueforti, P. paneum, P. carneum, and P. expansum. Differentiation of closely related mycotoxin producing fungi incubated on yeast extract sucrose agar has been achieved, indicating that there is a potential for predicting production of mycotoxins on food and feedstuffs by electronic nose analysis.
在这项工作中，描述了电子鼻分析用于区分密切相关真菌的潜力。通过电子鼻、气相色谱-质谱联用（GC-MS）和液相色谱-质谱联用（LC-MS）分析，对总共20株与奶酪相关的种别假丝地霉、卡门柏青霉、北欧青霉、罗克福特青霉及其密切相关的种别潘氏青霉、肉色青霉以及与奶酪无关的扩展青霉进行了研究。将分离株接种在20毫升顶空瓶中的酵母提取物蔗糖琼脂上，在7天的时间里每天进行电子鼻分析。为了评估电子鼻可能响应的挥发性代谢物，在培养的第7天和第8天之间，通过扩散采样将挥发性代谢物过夜收集到装有Tenax TA的试管上。通过气相色谱-质谱联用分析挥发性物质，结果表明在此阶段主要产生醇类（乙醇、2-甲基-1-丙醇和3-甲基-1-丁醇）和酮类（丙酮、2-丁酮和2-戊酮）。挥发性代谢物谱被证明具有种别特异性。在培养的第8天收集非挥发性代谢物，并通过高压液相色谱-二极管阵列检测器-飞行时间质谱联用进行霉菌毒素分析。在北欧青霉、罗克福特青霉、潘氏青霉、肉色青霉和扩展青霉的样品中检测到了几种霉菌毒素。已经实现了在酵母提取物蔗糖琼脂上培养的密切相关的产霉菌毒素真菌的区分，这表明通过电子鼻分析有预测食品和饲料中霉菌毒素产生的潜力。
