Multidrug resistance and prevalence of quinolone resistance genes of Salmonella enterica serotypes 4,[5],12:i:- in China
INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY
Authors: He, Jingjing; Sun, Fan; Sun, Dewei; Wang, Zhenyu; Jin, Shanshan; Pan, Zhiming; Xu, Zhengzhong; Chen, Xiang; Jiao, Xinan
Abstract
Salmonella 4,[5],12:i:- is a monophasic variant of Salmonella Typhimurium, which is responsible for global foodborne disease outbreaks. Here, 255 S. 4,[5],12:i:- strains isolated from humans (11.0%) or food-borne animals (89.0%) between 2010 and 2018 were examined. Tests of susceptibility to 19 antimicrobial agents using the broth micro dilution method showed that 99.2% (n = 253) of the isolates were resistant to at least one compound. Antibiotic susceptibility analysis demonstrated that 91.8% of the isolates were multidrug-resistant (MDR) strains with predominant resistance to tetracycline (90.6%), followed by resistance to ampicillin (86.3%), streptomycin (63.5%), chloramphenicol (62.7%), and trimethoprim-sulfamethoxazole (55.3%). The 5 major distinct patterns of multi-resistance were identified as R-type AST, R-type ACTSxt, R-type ACSTSxt, R-type ACGSTSxt and R-type ASTSxt. Among the PMQR genes examined in this study, oqxAB and aac (6')-Ib-cr were the most prevalent resistance genes in the multi-resistant isolates. Our findings highlight the prevalence of the resistance of S. 4,[5],12:i:- in some regions of China, and several common types of multidrug resistance phenotypes, to provide valuable information for epidemiological studies, risk management, and public health strategies.
Challenging a range of high pressure processing parameters to inactivate pathogens in orange juice
HIGH PRESSURE RESEARCH
Authors: Petrus, Rodrigo Rodrigues; Churey, John Joseph; Worobo, Randy William
Abstract
Among the non-thermal food technologies, high pressure processing (HPP) is currently the most widespread intervention in the juice industry. The study herein was conducted to challenge a wide range of pressure (401-599 MPa) and dwell time (87-313 s) in orange juice processing. The parameters were combined and targeted a minimum of 5-log cycle reductions in a cocktail for the pathogens of reference -Escherichia coliO157:H7,Salmonella entericaeListeria monocytogenes- inoculated into the juice. Eleven trials were carried out based on a central composite rotational design. All combinations of pressure and dwell time succeeded in reducing all pathogens.E. coliO157:H7 exhibited more resistance to HPP thanS. entericaandL. monocytogenes. The findings demonstrated that relatively low pressure (similar to 400 MPa) and short dwell time (similar to 200 s) can be successfully used to produce a safe orange juice.