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首页> 外文会议>Πανελληνιο Συνεδριο ΤροΦιμων >FACTORS CONTRIBUTING TO THE TRANSFER OF Escherichia coli O157:H7 BETWEEN CUTTING SURFACES AND FRESH PRODUCE; CROSS CONTAMINATION SENARIOS
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FACTORS CONTRIBUTING TO THE TRANSFER OF Escherichia coli O157:H7 BETWEEN CUTTING SURFACES AND FRESH PRODUCE; CROSS CONTAMINATION SENARIOS

机译：切割表面与新鲜产品之间大肠杆菌O157：H7转移的因素;交叉污染感

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Bacterial transfer events between biotic and abiotic surfaces are considered to be the major cause of cross contamination and consequently a risk for food safety. This study aimed to quantitatively determine the transfer of the pathogen Escherichia coli O157:H7 between leafy greens and equipment surfaces (cutting knives). Populations of the bacterium were evaluated during transfer: (i) from inoculated knives to fresh leafy greens, (ii) from inoculated greens to uninoculated knife, and (iii) from inoculated greens to knife and then to uninoculated greens. The number of leaves per cut, the types of vegetables (i.e, spinach, lettuce, cabbage) and the way that fresh produce was cut (vertically movement of the knife; V vs sliding the knive 5) were also evaluated for their impact on the pathogen's transfer. Sterilized knives were inoculated with a cocktail of three strains of f. coli O157:H7 (10~6 CFU/ml) and after 10 min (25°C) to allow the cells attach, knives were used for greens cutting. Three cuts were performed for every greens sample (20 g) and totally 10 samples (200 g) per knife were analyzed. Inoculated leafy green (6 log CFU/g, 5°C, 1h) was cut by sterilized knife 7 times, and the same contaminated knife was then used to cut 30 samples (600 g totally) of uninoculated product of the same type (7 cuts per sample). Spinach was the most favorable environment for pathogen's transfer from knives, resulting in a transfer population of 4.5-5 log CFU/g per cut for 30 cuts (200 g in total). For lettuce, there was a difference between the cutting method, since for V cutting the transfer rate of population was 3.7-4.7 log CFU/g per cut, while for S at 27-30 cuttings this population reduced to 2 log CFU/g. The lowest transfer was observed in cabbage leaves. Specifically, transfer rate was increased from 2 to 4 log CFU/g per cut and decreased from 3 to 0 log CFU/g per cut during V and S cutting, respectively. After 12 cuts, the levels of population transferred on samples were reduced to undetectable levels, with sporadic re-occurrence (1.7 log CFU/g) at 19-21 cuts. As the number of leaves increased (1-9), the transferred population of E. coli O157:H7 was constant for spinach (4.8-5.4 log CFU/g) and lettuce (4 log CFU/g), while an increasing rate (1-3.8 log CFU/g per cut) was observed in cabbage. The contamination of a sterilized knife by inoculated leaf (20 g, 6 log CFU/g) was capable of transferring the contamination to 600 g (210 cuttings) of fresh lettuce. The transferred population gradually reduced from 4 to 2 log CFU/g, during 140 cuttings (400 g). Results of the study revealed the significant impact of the type of fresh produce on the intensity of cross-contamination by E. coli O157:H7, with the greatest overall transfer generally seen on spinach. Once a contaminated sample enters a processing line, it can lead to an important cross-contamination of fresh-cut leafy greens. Further investigation should be performed to determine the factors contributing to cross-contamination, in order to ensure the safety of fresh-cut salads.
机译：生物和非生物表面之间的细菌转移事件被认为是交叉污染的主要原因，因此存在食品安全风险。这项研究旨在定量确定病原大肠杆菌O157：H7在绿叶蔬菜和设备表面（切刀）之间的转移。在转移过程中评估了细菌的种群：（i）从接种的刀到新鲜的绿叶蔬菜，（ii）从接种的蔬菜到未接种的刀，以及（iii）从接种的蔬菜到刀再到未接种的蔬菜。还评估了每次切割的叶子数量，蔬菜类型（例如，菠菜，生菜，卷心菜）以及新鲜产品的切割方式（刀的垂直移动; V对刀子的滑动5）对它们影响的影响。病原体的转移。消毒刀接种了三株f的混合物。大肠杆菌O157：H7（10〜6 CFU / ml），在10分钟（25°C）允许细胞附着后，用刀切割果岭。每个绿色蔬菜样品（20 g）进行三个切割，每把刀总共分析10个样品（200 g）。用消毒刀将接种的绿叶蔬菜（6 log CFU / g，5°C，1h）切开7次，然后用同一只受污染的刀切下30种样品（总共600 g）未接种的相同类型产品（7）。每个样本削减）。菠菜是最有利于病原体从刀子转移的环境，因此每割30割（总共200克）的转移种群为4.5-5 log CFU / g。对于生菜，切割方法之间存在差异，因为对于V切割，种群的转移速率为每切割3.7-4.7 log CFU / g，而对于S在27-30切割时，种群的迁移率降至2 log CFU / g。在甘蓝叶中观察到最低的转移。具体地，在V切割和S切割期间，传输速率分别从每次切割的2-4log CFU / g增加到每切割3至0log CFU / g。切割12次后，样品上转移的种群水平降至不可检测的水平，在19-21切割时出现零星的重复发生（1.7 log CFU / g）。随着叶片数量的增加（1-9），大肠杆菌O157：H7的转移种群对于菠菜（4.8-5.4 log CFU / g）和生菜（4 log CFU / g）都是恒定的，而增加的速率（在白菜中观察到1-3.8 log CFU / g（每切）。接种刀对消毒刀的污染（20 g，6 log CFU / g）能够将污染转移到600 g（210切块）新鲜的生菜中。在140次插穗（400 g）期间，转移的种群逐渐从4 log CFU / g降至2 log CFU / g。研究结果表明，新鲜农产品的类型对大肠杆菌O157：H7交叉污染的强度产生了显着影响，总体上最大的转移发生在菠菜上。一旦被污染的样品进入加工线，就可能导致鲜切叶类蔬菜的重要交叉污染。为了确保鲜切沙拉的安全性，应进行进一步调查以确定造成交叉污染的因素。

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