Parra-Flores Julio, Cerda-Leal Fabiola, Contreras Alejandra, Valenzuela-Riffo Nicole, Rodríguez Alejandra, Aguirre Juan
Molecular Microbiology Laboratory, Faculty of Health and Food Sciences, Universidad del Bío-Bío, Chillán, Chile.
Department of Agricultural Industry and Enology, Universidad de Chile, Santiago, Chile.
Front Microbiol. 2018 Jul 31;9:1708. doi: 10.3389/fmicb.2018.01708. eCollection 2018.
The objective of this study was to evaluate the presence of and microbiological parameters in dairy products associated with a food alert. Ninety dairy product samples were analyzed, including seven commercial brands and two product types (liquid and powdered) from four countries. Aerobic plate count (APC) and count were performed according to Chilean standards. spp. and were identified by polymerase chain reaction real time amplification of and genes and the genotype by multilocus sequence typing. Eighty-eight percent of dairy products showed APC higher than the detection limit. Fifty percent of liquid commercial brand samples contained APC: 2.6, 2.3, 1.1, and 2.9 CFU/mL in brands A, C, E, and G, respectively. Results for powdered commercial brands were 3.0, 3.6, and 5.7 CFU/g in brands B, D, and F, respectively. Maximum count (5.7 CFU/g) occurred in brand F dairy product manufactured in Chile. were found in 55% of the samples, 64% in liquid and 51% in powdered commercial brands. In 50% of brands B, D, and E, samples contained 2.9, 2.8, and 2.7 log CFU/g, respectively. Only liquid commercial brands from the United States had values between 0.1 and 4.5 CFU/mL. Seventeen suspicious strains were isolated and nine were identified as spp. Only eight suspicious strains from four powdered commercial brands (Chile and Singapore) were confirmed as by and gene amplification and sequencing. prevalence in the analyzed samples was 8.8%. There were 11% of powdered milk brands that contained APC between 4.0 and 4.7 log CFU/g and 55% of the samples contained . was found in dairy products manufactured in Chile and Singapore. On the basis of this information, the Chilean Ministry of Health (RSA) decreed a national and international food alert and recalled all the product batches that resulted positive in the present study from supermarkets and pharmacies.
本研究的目的是评估与一次食品警报相关的乳制品中的微生物参数。分析了90个乳制品样本，包括来自四个国家的七个商业品牌和两种产品类型（液体和粉末状）。需氧平板计数（APC）和大肠菌群计数按照智利标准进行。通过聚合酶链反应实时扩增stx1和stx2基因以及多位点序列分型鉴定志贺毒素大肠杆菌（STEC）血清型和stx基因型。88%的乳制品显示APC高于检测限。50%的液体商业品牌样本中，品牌A、C、E和G的APC分别为2.6、2.3、1.1和2.9 CFU/mL。粉末状商业品牌的结果是，品牌B、D和F的APC分别为3.0、3.6和5.7 CFU/g。最高计数（5.7 CFU/g）出现在智利生产的品牌F乳制品中。55%的样本中检测到大肠菌群，液体商业品牌中为64%，粉末状商业品牌中为51%。在50%的品牌B、D和E中，样本中的大肠菌群分别为2.9、2.8和2.7 log CFU/g。只有来自美国的液体商业品牌的大肠菌群值在0.1至4.5 CFU/mL之间。分离出17株可疑菌株，其中9株被鉴定为STEC血清型。只有来自四个粉末状商业品牌（智利和新加坡）的8株可疑菌株通过stx1和stx2基因扩增及stx测序被确认为STEC。分析样本中STEC的流行率为8.8%。11%的奶粉品牌的APC在4.0至4.7 log CFU/g之间，55%的样本中含有STEC。在智利和新加坡生产的乳制品中发现了STEC。基于此信息，智利卫生部（RSA）发布了国内和国际食品警报，并从超市和药店召回了本研究中检测结果呈阳性的所有产品批次。
