Dipartimento di Medicina Veterinaria, Università degli Studi di Sassari, Italy.
Dipartimento di Medicina Veterinaria, Università degli Studi di Sassari, Italy.
Food Microbiol. 2018 Sep;74:86-91. doi: 10.1016/j.fm.2018.03.007. Epub 2018 Mar 13.
The aim of the present study was to investigate the effect of short purification cycles on the safety of naturally contaminated Mytilus galloprovincialis from harvesting areas of the Gulf of Olbia (Sardinia, Italy). Samples from ten batches of mussels were collected before, during and after purification treatment at two purification centres (A-B). All the samples were analysed for Escherichia coli and Salmonella spp according to Council Regulation (EC) 2285/2015. Detection and enumeration of Vibrio spp were performed according to previously published methods. Presumptive identification of Vibrio spp isolates were performed by means of conventional biochemical tests and polymerase chain reaction. The presence of Hepatitis A virus was detected by nested reverse transcriptase-polymerase chain reaction. Environmental parameters (water temperature and salinity) were also recorded. The results of Escherichia coli counts showed the overall efficacy of the short purification cycles; a purification cycle of 8 h led to a rapid decline in the concentration. The decrease in Escherichia coli counts does not correlate with the presence of naturally occurring vibrios, the decline of which occurs at an even slower rate. The average contamination levels for Vibrio spp before purification were 8.20 ± 0.47 and 7.99 ± 0.62 Log CFU/g in samples collected at purification plants A and B, respectively. After purification, the average contamination levels were 8.10 ± 0.60 Log CFU/g at purification plant A and 7.85 ± 0.57 Log CFU/g at purification plant B. The contaminated samples revealed the presence of Vibrio alginolyticus (n=21), Vibrio fluvialis (n=12), Vibrio cholerae (n=4), Vibrio parahaemolyticus (n=2) and Vibrio vulnificus (n=1). The Vibrio parahaemolyticus isolates carried the tdh or the trh genes. None of the isolates was tdh+/trh+. Salmonella spp and Hepatitis A virus were not detected. The adoption of short purification cycles for Mytilus galloprovincialis in the presence of pathogenic vibrios might not be sufficient to guarantee the safety of consumers.
本研究的目的是调查短净化周期对来自意大利奥尔比亚湾（撒丁岛）捕捞区受污染贻贝（Mytilus galloprovincialis）安全性的影响。在两个净化中心（A-B），在净化处理之前、期间和之后，从十批贻贝中采集了样本。根据理事会法规（EC）2285/2015，所有样本均按照大肠杆菌和沙门氏菌 spp 进行了分析。按照先前发表的方法进行了弧菌 spp 的检测和计数。通过常规生化试验和聚合酶链反应对 Vibrio spp 分离株进行了推定鉴定。通过巢式逆转录聚合酶链反应检测了甲型肝炎病毒的存在。还记录了环境参数（水温盐度）。大肠杆菌计数的结果表明，短净化周期的整体效果；8 小时的净化周期导致浓度迅速下降。大肠杆菌计数的减少与自然存在的弧菌无关，后者的减少速度甚至更慢。在净化厂 A 和 B 分别采集的样本中，净化前 Vibrio spp 的平均污染水平分别为 8.20±0.47 和 7.99±0.62 Log CFU/g。净化后，净化厂 A 的平均污染水平为 8.10±0.60 Log CFU/g，净化厂 B 的平均污染水平为 7.85±0.57 Log CFU/g。受污染的样本显示存在 Algino lyticus 弧菌（n=21）、Fluvialis 弧菌（n=12）、霍乱弧菌（n=4）、副溶血性弧菌（n=2）和 Vulnificus 弧菌（n=1）。副溶血性弧菌分离株携带 tdh 或 trh 基因。没有分离株是 tdh+/trh+。未检测到沙门氏菌 spp 和甲型肝炎病毒。在存在致病性弧菌的情况下，对贻贝进行短净化周期处理可能不足以保证消费者的安全。
