AUTHOR=Parra-Flores Julio , Cerda-Leal Fabiola , Contreras Alejandra , Valenzuela-Riffo Nicole , Rodríguez Alejandra , Aguirre Juan 

TITLE=Cronobacter sakazakii and Microbiological Parameters in Dairy Formulas Associated With a Food Alert in Chile

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.01708

DOI=10.3389/fmicb.2018.01708

ISSN=1664-302X

ABSTRACT=<p>The objective of this study was to evaluate the presence of <italic>Cronobacter sakazakii</italic> 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 <italic>Enterobacteriaceae</italic> count were performed according to Chilean standards. <italic>Cronobacter</italic> spp. and <italic>C. sakazakii</italic> were identified by polymerase chain reaction real time amplification of <italic>rpoB</italic> and <italic>cgcA</italic> 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. <italic>Enterobacteriaceae</italic> 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 <italic>Enterobacteriaceae</italic> values between 0.1 and 4.5 CFU/mL. Seventeen suspicious strains were isolated and nine were identified as <italic>Enterobacter</italic> spp. Only eight suspicious strains from four powdered commercial brands (Chile and Singapore) were confirmed as <italic>C. sakazakii</italic> by <italic>rpoB</italic> and <italic>cgcA</italic> gene amplification and <italic>fusA</italic> sequencing. <italic>C. sakazakii</italic> 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 <italic>Enterobacteriaceae</italic>. <italic>C. sakazakii</italic> 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.</p>