Research Publications (Food Safety)

S. enteritidis and P. aeruginosa had an inhibitory effect on L. plantarum. L. plantarum had no effects on S. enteritidis and P. aeruginosa. Lotka–Volterra model with six interaction coefficients could quantitatively describe the interaction among Salmonella enteritidis, Lactobacillus plantarum, and Pseudomonas aeruginosa.

Copper is essential, but highly toxic. Direct responses of bacteria to excess copper, collectively termed copper homeostasis systems, are well known, but how copper causes toxicity is unclear. This review summarizes how both direct copper homeostasis responses, and indirect accessory stress‐response pathways are essential to resisting copper toxicity among enterobacteria. Abstract Copper is a required micronutrient for bacteria and an essential cofactor for redox‐active cuproenzymes.

The market of ready‐to‐eat minimally processed vegetables (RTE‐MPV) is increasing in Brazil and many other countries. During processing, these vegetables go through several steps that modify their natural structure while maintaining the same nutritional and sensory attributes as the fresh produce. One of the most important steps is washing‐disinfection, which aims to reduce the microbial load, prevent cross‐contamination and inactivate pathogenic microorganisms that may be present.

Salmonella enterica is an important gastrointestinal and facultative intracellular pathogen. After invasion of host cells, it resides in a specialized, replication-permissive compartment, the Salmonella-containing vacuole (SCV). During maturation of the SCV, Salmonella remodels the host endosomal system to form a variety of membranous extensions from the SCV, one type designated Salmonella-induced filaments (SIFs).

Author(s): Daizy Hwang, Michael J. Rothrock, Hao Pang, Govindaraj Dev Kumar, Abhinav Mishra

by G. Girgis, M. Powell, M. Youssef, D. E. Graugnard, W. D. King, K. A. Dawson

Author(s): Govindaraj Dev Kumar, Jitendra Patel, Sadhana Ravishankar

Aims To evaluate tomato epiphyte lactic acid bacteria (LAB) hydrophobicity and auto‐aggregation as an indicator of bacteria adhesion to tomato. Likewise use LAB adhesion and co‐aggregation as mechanisms to antagonize pathogen attachment. Methods and Results Fifty‐four LAB were screened to evaluate their hydrophobic, auto‐ and co‐aggregative properties against Salmonella Typhimurium, Saintpaul, Montevideo and Escherichia coli O157:H7.

Prolonged exposure of foodborne pathogens (Salmonella Enteritidis [SE], Escherichia coli O157:H7 [EC], and Listeria monocytogenes [LM]) to acid, salt, and cold stress alters their antibiotic resistance. However, the effect of acid, salt, and cold stress on bacterial antibiotic resistance depend on both the bacterial species and the specific antibiotic.

This research study was based on ultraviolet (UVC) light and a combination of UVC-ozone treatments that have recently received attention from the beef processing industry as antimicrobial interventions that leave no chemical residues on products. The objectives were to evaluate effectiveness of UVC and UVC in combination with gaseous ozone treatments for inactivation of pathogenic bacteria on fresh beef and the impact on fresh beef quality.

A strain of extensively drug-resistant (XDR) Salmonella enterica serovar Typhi has caused a large ongoing outbreak in Pakistan since 2016. In Ontario, Canada, 10 cases of mainly bloodstream infections (n = 9) were identified in patients who traveled to Pakistan. Whole-genome sequencing showed that Canadian cases were genetically related to the Pakistan outbreak strain.

Author(s): Ying Li, Xiaorong Yang, Huaning Zhang, Huayun Jia, Xiaoge Liu, Bo Yu, Yingchun Zeng, Yu Zhang, Xiaoyan Pei, Dajin Yang

Autophagy is an important component of the innate immune system in mammals. Low levels of basic autophagy are sustained in normal cells, to help with the clearance of aging organelles and misfolded proteins, thus maintaining their structural and functional stability. However, when cells are faced with challenges, such as starvation or pathogenic infection, their level of autophagy increases significantly.

Animal proteins are essential elements of human and animal feed chain and improving the safety of human and animal feed requires understanding and controlling of the transmission of infectious agents in food chain. Many pathogenic infectious agents, such as prion protein is known to damage the central nervous system in the cattle. Bovine spongiform encephalopathy (BSE) results from infection agent (prion), and affects number of species such as cattle, human, and cats.

Brucellosis is a serious zoonosis occurring mainly in developing countries, and its diagnosis is largely dependent on serologic detection and bacterial culture. In this study, we developed the murine monoclonal antibodies (mAbs) against a conserved and major outer membrane protein 25 (Omp25) of Brucella species (B. spp.) for use in clinical diagnosis.

This study was conducted to evaluate the antimicrobial effect of medium chain fatty acids (MCFAs) against Salmonella Typhimurium (ATCC 14028) when used in dry dog food kibbles. Minimum inhibitory concentration (MIC) of three MCFAs, namely caproic (C6), caprylic (C8) and capric (C10) acids were determined using the broth micro and macro-dilution assay technique.  Using canola oil as a fat coating, the efficacy of each MCFA was then tested on dry dog food kibbles at 37°C for up to 5 h.

Flagellar gene expression is bimodal in Salmonella enterica. Under certain growth conditions, some cells express the flagellar genes whereas others do not. This results in mixed populations of motile and non-motile cells. In the present study, we found that two independent mechanisms control bimodal expression of the flagellar genes. One was previously found to result from a double negative-feedback loop involving the flagellar regulators RflP and FliZ.

Author(s): Xinyi Pang, Lin Chen, Hyun-Gyun Yuk

Surface water is prone to bacterial contamination as it receives wastes and pollutants from human and animal sources, and contaminated water may expose local populations to health risks. This review provides a brief overview on the prevalence and antimicrobial resistance (AR) phenotypes of Salmonella, Escherichia coli, and Enterococcus, found in natural freshwaters.

The effects of soil type and temperature on the survival of a cocktail of five Salmonella enterica serotypes (Enteritidis, Infantis, Montevideo, Typhimurium and Zanzibar) in manure‐amended soils under controlled laboratory conditions was assessed. Containers of clay loam or sandy soil, unaltered or amended with 2% (w/w) poultry manure, were inoculated with S. enterica (~5 log10 CFU g‐1) and held at 5, 21 or 37°C for 6 weeks. Statistical analysis of the persistence of S.

This study was aimed at assessing whether the repeated exposure of 12 strains of Salmonella spp., Escherichia coli, and Listeria monocytogenes to alternative nonthermal decontamination techniques with UV light (UV-C) and nonthermal atmospheric plasma (NTAP) may cause the emergence of variants showing increased resistance to clinically relevant antibiotics (ampicillin, cefotaxime, ciprofloxacin, gentamicin, streptomycin, tetracycline, erythromycin, vancomycin, and colistin).

Author(s): Chih-Hsien Lin, Jing-Fang Huang, Yu-Fen Sun, Peter J. Adams, Jiunn-Horng Lin, Ian D. Robertson

ABSTRACT Antimicrobial treatment regimens against bacterial pathogens are designed using the drug's minimum inhibitory concentration (MIC) measured at a bacterial density of 5.7 log10(colony-forming units (CFU)/mL) in vitro. However, MIC changes with pathogen density, which varies among infectious diseases and during treatment. Incorporating this into treatment design requires realistic mathematical models of the relationships.

The rapid detection of foodborne microbial pathogens contaminating fresh fruits and vegetables during the intervening period between harvest and consumption could revolutionize microbial quality assurance of food usually consumed raw and those with a limited shelf life. We have developed a sensitive, shotgun whole genome sequencing protocol capable of detecting as few as 1 colony forming unit (cfu) of Salmonella enterica serovar Typhimurium spiked on 25 g of lettuce.

Organic farming, including integrated crop-livestock farms (ICLF) and backyard farming (BF), are gaining popularity in the US, and products from these farms are commonly sold in farmers markets, local stores, or roadside stalls. Due to avoiding use of antibiotics and chemicals, as well as the non-professional harvesting and packaging methods, and the use of composted animal waste, there is an increased risk of cross-contamination with zoonotic pathogens.