Research Publications (Food Safety)

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a principally foodborne pathogen linked to serious diseases, including bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. Comparative genomics analysis revealed that EHEC O157 contains 177 unique genomic islands, termed O islands, compared with the nonpathogenic E. coli K-12 laboratory strain.

The ppk1 gene encodes polyphosphate kinase (PPK1), which is the major catalytic enzyme that Escherichia coli utilizes to synthesize inorganic polyphosphate (polyP). The aim of this study was to explore the role of PPK1 in the pathogenesis of Enterohemorrhagic E. coli O157:H7 (EHEC O157:H7).

Abstract
Background
Enterohemorrhagic Escherichia coli (EHEC) are responsible for severe diseases in humans, and the ruminant digestive tract is considered as their main reservoir. Their excretion in bovine feces leads to the contamination of foods and the environment. Thus, providing knowledge of processes used by EHEC to survive and/or develop all along the bovine gut represents a major step for strategies implementation.

Journal of Food Safety, EarlyView. The objective of this study was to investigate the effect of dielectric-barrier discharges plasma (DBDP) treatment against Escherichia coli O157:H7 and Staphylococcus aureus in different types of food matrix. Dried julienned squid (DS), squid powder (SP), beef jerky (BJ), and beef powder (BP) were inoculated with E. coli O157:H7 or S. aureus and treated with DBDP. The treatment voltage varied at 6.11, 9.25, and 11.86 kV.

Shiga toxin-producing Escherichia coli (STEC) can cause severe infections in humans, leading to serious diseases and dangerous complications, such as hemolytic-uremic syndrome. Although cattle are a major reservoir of STEC, the most commonly occurring source of human infections are food products (e.g., vegetables) contaminated with cow feces (often due to the use of natural fertilizers in agriculture).

Journal of Applied Microbiology, Accepted Article. Abstract
Aims
The biological events occurring during human digestion help understand the mechanisms underlying the dose-response relationships of enteric bacterial pathogens. To better understand these events, we investigated the growth and reduction behavior of bacterial pathogens in an in vitro model simulating the environment of the small intestine.

Rapid and credible detection of pathogens is essential to prevent and control outbreaks of foodborne diseases. In this study, a poly-l-lysine-functionalized magnetic beads (PLL-MB) strategy combined with a PCR assay was established to detect Staphylococcus aureus. We also detected Escherichia coli O157:H7 to further verify the strategy for gram-negative bacteria detection.

Fresh produce continues to be the main source of foodborne illness outbreaks in the United States implicating bacterial pathogens such as Escherichia coli O157:H7 (EHEC). The efficacy of nanoemulsified carvacrol (NCR) as a washing treatment in reducing EHEC on fresh produce was investigated. Fresh baby spinach, Romaine lettuce, and Iceberg lettuce leaves (2.5 cm diameter cores) were spot-inoculated with a five-strain cocktail of nalidixic acid resistant EHEC at ~ 6 log CFU/cm 2 .

Escherichia coli O157:H7 is one of the pathogenic bacteria causing foodborne disease. The use of lytic bacteriophages can be a good solution to overcome the disease. This study is aimed at isolating lytic bacteriophages from environmental sewage with E. coli O157:H7 bacterial cells. The sample used in this study was eight bacteriophages, and the technique used in identifying E. coli O157:H7 carriers of the stx1 and stx2 genes was PCR.

Previous empirical evidence has demonstrated that low socioeconomic status (SES) communities have higher rates of gastroenteritis; however, there is a paucity of literature on the safety and quality of food (fresh produce) accessible to these communities. The overarching goal of this study was to investigate the microbial safety and quality of fresh leafy greens from low and high SES neighborhoods in the Houston, Texas area.

Many antibiotic resistance genes present in human pathogenic bacteria are believed to originate from environmental bacteria. Conjugation of antibiotic resistance conferring plasmids is considered to be one of the major reasons for the increasing prevalence of antibiotic resistances. A hotspot for plasmid-based horizontal gene transfer is the phyllosphere, i.e., the surfaces of aboveground plant parts.

Arabinose is a major plant aldopentose in the form of arabinans complexed in cell wall polysaccharides or glycoproteins (AGP), but comparatively rare as a monosaccharide.

Journal of Food Processing and Preservation, Accepted Article. Abstract The aim of this study was to investigate the effect of ascorbic, citric and lactic acid (1% and 5%) on the survival of Listeria (L.) monocytogenes and Escherichia (E.) coli O157:H7 inoculated on fresh Atlantic salmon stored at 4 ± 1°C. In this study, in general, L. monocytogenes and E. coli O157: H7 population in samples treated with organic acids were significantly lower than in non-treated fish samples.

Journal of Applied Microbiology, Accepted Article. ABSTRACT
Aims
In this study, the efficacy of using vacuumed hydrogen peroxide vapor (VHPV) to inactivate foodborne pathogens in whole dried black pepper (Piper nigrum) and powdered dried red pepper (Capsicum annuum) was evaluated.

Escherichia coli O157:H7 is an important foodborne pathogen but largely under investigated in Africa. The objectives of this study were to estimate the prevalence and pattern of antimicrobial resistance of E. coli O157:H7 in lettuce in Addis Ababa, Ethiopia. A total of 390 retail lettuce samples were collected across the 10 subcities of Addis Ababa. E. coli O157:H7 was isolated and identified following ISO-16654:2001 standard.

In-home or food service antimicrobial treatment options for fresh produce are limited. Hot water treatments for whole (unpeeled) produce have been proposed but data to support this practice for onions are not available. Separate cocktails of rifampin-resistant Escherichia coli O157:H7, Listeria monocytogenes , or Salmonella were cultured on agar and suspended in sterile water.

Diseases caused by harmful microorganisms pose a serious threat to human health. Safe and environment-friendly disinfectants are, therefore, essential in preventing and controlling such pathogens. This study aimed to investigate the antimicrobial activity and mechanism of a novel hydrogen peroxide and silver (H 2 O 2 -Ag + ) complex (HSC) in combatting Staphylococcus aureus ATCC 29213, Escherichia coli O157:H7 NCTC 12900 and Salmonella typhimurium SL 1344.

International Journal of Food Science & Technology, Accepted Article. The development of effective natural antibacterial agents is important due to the insecurity of synthetic antimicrobial agents and consumer preferences. In this study, kojic acid (KA) and tea polyphenols (TP) were found to exhibit synergistic inhibitory effect against Escherichia coli O157:H7 with a fractional inhibitory concentration index of 0.25.

The objective of this study was to evaluate the inhibitory effect of lactic acid (LA) and peroxyacetic acid (PAA) on the biofilm formation of Escherichia coli O157:H7 in beef extract (BE). BE medium was used as the growth substrate in this study, to make the control effect closer to the situation of the factory. The biofilm inhibitory efficacy of LA and PAA was tested by using a crystal violet staining assay and microscopic examination.

Persisters are a form of dormancy in bacteria that provide temporary resistance to antibiotics. The following reports on the formation of Escherichia coli O157:H7 E318 type II persisters from a protracted (8 days) challenge with ampicillin. Escherichia coli O157:H7 followed a multiphasic die-off pattern with an initial rapid decline (Phase I) of susceptible cells that transitioned to a slower rate representing tolerant cells (Phase II).

Several classes of non-antibiotic drugs, including psychoactive drugs, proton-pump inhibitors (PPIs), non-steroidal anti-inflammatory drugs (NSAIDs), and others, appear to have strong antimicrobial properties. We considered whether psychoactive drugs induce the SOS response in E. coli bacteria and, consequently, induce Shiga toxins in Shiga-toxigenic E. coli (STEC). We measured the induction of an SOS response using a recA-lacZ E.

Escherichia coli O157:H7 strains often produce Shiga toxins encoded by genes on lambdoid bacteriophages that insert into multiple loci as prophages. O157 strains were classified into distinct clades that vary in virulence. Herein, we used PCR assays to examine Shiga toxin (Stx) prophage occupancy in yehV, argW, wrbA, and sbcB among 346 O157 strains representing nine clades.

Escherichia coli can cause intestinal diseases in humans and livestock, destroy the intestinal barrier, exacerbate systemic inflammation, and seriously threaten human health and animal husbandry development. The aim of this study was to investigate whether the antimicrobial peptide mastoparan X (MPX) was effective against E. coli infection. BALB/c mice infected with E. coli by intraperitoneal injection, which represents a sepsis model.

The release of Escherichia coli (E. coli) O157:H7 has been widely found in various environments, but little is known about the probable influence of the transient E. coli O157:H7 invasion on the native microbial community. Here, we investigated the temporal response of two bacterial biospheres (abundant and rare) of two marsh sediments against E. coli O157:H7 during a 60-day incubation. The diversity of both biospheres showed no evident response to O157:H7 invasion.