Publications by authors named "Doris H D'Souza"

The utility of bicontinuous microemulsions (BMEs) as carriers of the antimicrobial peptide (AMP) gramicidin D and antiseptic chlorhexidine was investigated for possible topical delivery to chronic wounds. The two water-insoluble solutes dissolved in pre-formed one-phase BMEs of Water/ Polysorbate 80/ Limonene/ Ethanol/ Glycerol and Water/ Aerosol-OT (AOT)/ Polysorbate 85/ Isopropyl Myristate and an AOT/ Polysorbate 85 Winsor-III system, achieving gramicidin and chlorhexidine concentrations of 1.0 (wt)% and 0.

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Hepatitis A viral outbreaks continue to occur. It can be transmitted through aerosolized droplets and thus can contaminate surfaces and the environment. Ultraviolet light emitting diode (UV-C LED) systems are used for inactivation of microbes, though research is needed to determine optimal doses for aerosolized HAV inactivation.

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Shiga toxin-producing Escherichia coli (STEC) is causing outbreaks worldwide and a rapid detection method is urgently needed. Loop-mediated isothermal amplification (LAMP) has attracted attention in the development of pathogen detection methods; however, current methods for the detection of LAMP amplicon suffer some drawbacks. In this study, we designed a new LAMP method by incorporating peroxidase-mimicking G-quadruplex DNAzyme for a simple colorimetric detection of the LAMP amplicon.

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Foodborne bacteria like Escherichia coli threaten global food security, necessitating affordable, on-site detection methods, especially in resource-limited settings. This study optimized loop-mediated isothermal amplification (LAMP) integrated with peroxidase-mimicking G-quadruplex DNA structures (DNAzyme), termed DNAzyme-LAMP which was designed to incorporate two different catalytic DNAzymes per amplification unit, enabling colorimetric detection of E. coli in leafy vegetables and milk samples.

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Food contact surfaces can harbor and transmit pathogens leading to outbreaks. Decontamination strategies that are user- and environmentally-friendly without toxic by-product formation are needed. Novel UV-C light-emitting diode (LED) technologies are being explored to deliver the required dose to inactivate viruses in food-processing environments.

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Ongoing challenges with reproducible human norovirus cultivable assays necessitate the use of surrogates, such as feline calicivirus (FCV-F9) and Tulane virus (TV), during inactivation studies. Chlorine alternates used as control strategies include aqueous and gaseous ozone. This study aimed at determining the inactivation of FCV-F9 and TV by a portable ozone-generating device.

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Article Synopsis
  • - The study explores the solubilization of melittin, an antimicrobial peptide, in bicontinuous microemulsions (BMEs) made with biocompatible oils, demonstrating its capacity to stay active and effective against bacteria in chronic wounds and surgical infections.
  • - The researchers analyzed different BME systems, finding that melittin maintained an active α-helix configuration in an apolar environment, particularly in the Winsor-III system, which enhanced its interaction with surfactants and improved its antimicrobial properties.
  • - The results revealed that while melittin-free BMEs already inhibited bacteria due to their oil content, adding melittin significantly increased antimicrobial activity, suggesting that BMEs could serve as effective delivery platforms
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Inflammatory bowel disease (IBD) is a chronic inflammatory condition that can cause severe damage to the gastrointestinal tract leading to lower quality of life and productivity. Our goal was to investigate the protective effect of the soy peptide lunasin in an in vivo model of susceptibility to IBD and to identify the potential mechanism of action in vitro. In IL-10 deficient mice, oral administration of lunasin reduced the number and frequency of mice exhibiting macroscopic signs of susceptibility to inflammation and significantly decreased levels of the proinflammatory cytokines TNF-α, IL-1β, IL-6, and IL-18 by up to 95%, 90%, 90%, and 47%, respectively, in different sections of the small and large intestines.

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Aqueous extracts of Quillaja saponaria Molina are US FDA approved as food additives in beverages with known antiviral activity. Due to lack of commercially available vaccines against human noroviruses (HNoVs), alternate methods to prevent their spread and the subsequent emergence of variant strains are being researched. Furthermore, HNoVs are not yet culturable at high enough titers to determine inactivation, therefore surrogates continue to be used.

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The antimicrobial potential of switchgrass extractives (SE) was evaluated on cut lettuce leaves and romaine lettuce in planta, using rifampicin-resistant Escherichia coli O157:H7 and Salmonella Typhimurium strain LT2 as model pathogens. Cut lettuce leaves were swabbed with E. coli O157:H7 or S.

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Antimicrobials have been widely used in dairy farms to prevent and control dairy cattle diseases since 1960s. This led to the emergence of antimicrobial resistant bacteria (ARB) that, along with their antimicrobial resistance genes (ARGs), can spread from dairy farms to humans. Therefore, regular antimicrobial resistance (AMR) monitoring is important to implement proper mitigation measures.

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A study was carried out from August 2017 to February 2018 on lactating dairy cows, one-humped dromedary camels, and goats to determine mastitis in the Bule Hora and Dugda Dawa districts of in Southern Ethiopia. Milk samples from 564 udder quarters and udder halves from 171 animals consisting of 60 dairy cows, 51 camels, and 60 goats were tested for mastitis. Sixty-four positive udder milk samples were cultured, and bacterial mastitis pathogens were isolated and identified.

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Hemicellulose, a structural polysaccharide and often underutilized co-product stream of biorefineries, could be used to produce prebiotic ingredients with novel functionalities. Since hot water pre-extraction is a cost-effective strategy for integrated biorefineries to partially fractionate hemicellulose and improve feedstock quality and performance for downstream operations, the approach was applied to process switchgrass (SG), hybrid poplar (HP), and southern pine (SP) biomass at 160°C for 60 min. As a result, different hemicellulose-rich fractions were generated and the chemical characterization studies showed that they were composed of 76-91% of glucan, xylan, galactan, arabinan, and mannan oligosaccharides.

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Aichi virus (AiV) that results in gastroenteritis worldwide, is spread through contaminated shellfish and water. The resistance/tolerance of AiV to common inactivation processes along with the absence of commercially available vaccines makes it necessary to study its thermal inactivation kinetics. This research evaluated the heat inactivation of AiV in cell-culture media using 2-ml sterile glass vials by the linear and Weibull models.

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Aichi virus (AiV) is an enteric virus that affects humans and is prevalent in sewage waters. Effective strategies to control its spread need to be explored. This study evaluated grape seed extract (GSE) for: a) antiviral potential towards AiV infectivity at 37 °C and room temperature (RT); b) antiviral behavior in model foods (apple juice (AJ) and 2% fat milk) and also simulated gastric environments; and c) potential application as a wash solution on stainless steel surfaces.

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Rapid and sensitive detection of live/infectious foodborne pathogens is urgently needed in order to prevent outbreaks and food recalls. This study aimed to (1) evaluate the incorporation of propidium monoazide (PMA) into PCR or LAMP assays to selectively detect viable Salmonella Enteritidis following sublethal heat or UV treatment, and autoclave sterilization; and (2) compare the detection of PMA-PCR and PMA-LAMP to DNA-based PCR and LAMP (without PMA), RNA-based RT-PCR and RT-LAMP, and culture-based methods. Nucleic acids (DNA or RNA) from 1-mL S.

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Background: Exosomes are extracellular vesicles involved in intercellular communication. The objectives were to characterize bovine milk exosomes (BME) and determine its effect on RAW 264.7 macrophages.

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Human noroviruses (HNoV) and hepatitis A virus (HAV) are predominantly linked to foodborne outbreaks worldwide. As cell-culture systems to propagate HNoV in laboratories are not easily available, Tulane virus (TV) is used as a cultivable HNoV surrogate to determine inactivation. Heat-sensitization of HAV and TV by "generally recognized as safe'' (GRAS) substances can potentially reduce their time-temperature inactivation parameters during processing to ensure food safety.

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Blueberry polyphenols are known for their high antioxidant and antimicrobial potential. Aichi virus (AiV) is an emerging human enteric virus that causes gastroenteritis outbreaks worldwide. This study aimed to (1) determine the time- and dose-dependent effects of blueberry proanthocyanidins (B-PAC) against AiV over 24 h at 37 °C; (2) gain insights on their mode of action using pre- and post-treatment of host cells and Transmission Electron Microscopy; and (3) determine their anti-AiV effects in model foods and under simulated gastric conditions.

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Human noroviruses (HNoVs) cause significant gastrointestinal disease outbreaks worldwide. Tulane virus (TV) is a cultivable HNoV surrogate widely used to determine control measures against HNoVs. The objective of this study was to determine the heat inactivation kinetics (D- and z-values) of TV in cell-culture media and on spiked homogenized spinach using the first-order and Weibull models.

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Plant polyphenols have shown antiviral activity against several human pathogens, but their physicochemical interactions are not well-understood. The objectives of this study were to compare the antiviral activity between monomeric catechin and dimeric procyanidin B2 (PB2) using cultivable human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)) and to understand their potential antiviral mechanism using virus-like particles (VLPs) and the P domain of human norovirus GII (HNoV GII.4).

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Human noroviruses (HNoVs) are primarily transmitted by the fecal-oral route, either by person-to-person contact, or by ingestion of contaminated food or water as well as by aerosolization. Moreover, HNoVs significantly contribute to foodborne diseases being the causative agent of one-fifth of acute gastroenteritis worldwide. As a consequence of globalization, transnational outbreaks of foodborne infections are reported with increasing frequency.

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High intensity ultrasound (HIU) continues to be researched as a nonthermal inactivation technology of appeal to food manufacturers. The advantages of HIU include maintenance of product quality, freshness, product homogenization, along with simultaneous inactivation of pathogens. Besides, it is simple, relatively inexpensive, and easily adaptable to most processing environments.

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Staphylococcus aureus is a frequent and major contagious mastitis bacterial pathogen. The antibiotic treatment cure rates vary considerably from 4% to 92%. Staphylococcus aureus readily becomes resistant to antibiotics, resulting in persistent noncurable intramammary infection that usually results in culling of infected animals.

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