Antimicrobial effects of copper and brass ions on the growth of Listeria monocytogenes at different temperatures, pH and nutrients

Listeria monocytogenes has been recognized as a human pathogen since 1929. This pathogen is found in many foods and listeriosis infections affect approximately 2,500 people in the United States each year, according to the Centers for Disease Control and Prevention. Of those infected with L. monocytogenes approximately 500 die as a result of the illness. Listeria monocytogenes is a bacterium, commonly found in water, soil, plant material, animals and human. Today, different methods are used by food manufacturers, to reduce the risk of Listeria monocytogenes, such as antimicrobial agents, heating, irradiation, and fermentation. The ability of the bacteria to grow at temperatures as low as 3°C permits multiplication in refrigerated foods. The purpose of this study was to determine the antimicrobial effect of copper ions against Listeria monocytogenes on the surface of copper, brass and concrete coated with polyurethane containing different concentrations of copper ions. The utilization of pH, nutrients and temperatures were applied. Copper alloys antimicrobial effect in two different crawfish processing plants was also evaluated. The amount of copper ions released into raw and cooked shrimp at different temperatures was also assessed. Our study has been successful in understanding the survival of Listeria monocytogenes at different copper ions concentrations under different temperatures, pH and nutrients. It has also been observed that the use of different copper ions concentrations haves great potential as antimicrobial agents that can be employed by food processors

Essential Oils: Partnering with Antibiotics

Essential oils (EO) are volatile, non-lipid-based oils produced as a plant defense mechanism. Studies from our group have validated the potential usefulness of EOs to synergistically and additively work with antibiotics. In this book chapter, we aim to outline some background on the EOs and their uses and applications, to discuss the different mechanisms of action in partnering with antibiotics, and, finally, to explore their potential use against multidrug-resistant bacteria. Applications of EO in therapy will enable the revival of previously sidelined antibiotics and enhance the development of new drug regimens to better mitigate what may be the biggest health challenge by year 2050

Innovations in MDR therapy: essential oil applications

There are three common outcomes when testing the application of combinatory therapies for potential use in the clinical setting against multi-drug resistant (MDR) bacteria; whether synergistic, additive or antagonistic. Due to their relatively more favourable outcomes, antibiotics and adjuvant achieving synergism have been the primary focus in the development of therapeutics thus far; this has also resulted in less attention given to additive interactions, which may be equally effective. Hence, in this study, the authors investigated the effects of additivity using a representative combination model involving Cinnamomum verum (cinnamon bark) essential oil (CBO) and meropenem, a carbapenem class of antibiotics. Based on the zeta potential measurements, outer membrane permeability and scanning electron microscopy, synergistic and additive interactions of cinnamon bark oil (CBO) indicated comparable bacterial membrane disruption, alluding similar degrees of cell perturbations at the molecular level. Results from this study suggests that further investigations should be looked into for combinatorial therapeutic pairs achieving additive indices so as not to disqualify potentially useful alternatives in antibiotic therapy

Survival and growth of Cronobacter species (Enterobacter) sakazakii in wheat-based infant follow on formulas

Aim: To determine the survival and growth characteristics of Cronobacter species (Enterobacter sakazakii) in infant wheat-based formulas reconstituted with water, milk, grape juice or apple juice during storage. Methods and Results: Infant wheat-based formulas were reconstituted with water, UHT milk, pasteurized grape or apple juices. The reconstituted formulas were inoculated with C. sakazakii and C. muytjensii and stored at 4, 25 or 37°C for up to 24h. At 25 and 37°C, Cronobacter grew more (>5 logio) in formulas reconstituted with water or milk than those prepared with grape or apple juices (ca. 2-3 logio). The organism persisted, but did not grow in any formulas stored at 4°C. Formulas reconstituted with water and milk decreased from pH 6.0 to 4.8-5.0 after 24h, whereas the pH of the formulas reconstituted with fruit juices remained at their initial pH values, ca. pH 4.8-5.0. Conclusion: C sakazakii and C muytjensii can grow in reconstituted wheat-based formulas. If not immediately consumed, these formulas should be stored at refrigeration temperatures to reduce the risk of infant infection. Significance and Impact of the Study: The results of this study will be of use to regulatory agencies and infant formula producers to recommend storage conditions that reduce the growth of Cronobacter in infant wheat-based formulas

The missing piece: recent approaches investigating the antimicrobial mode of action of essential oils

Antibiotic resistance is a major global health issue that has seen alarming rates of increase in all parts of the world over the past two decades. The surge in antibiotic resistance has resulted in longer hospital stays, higher medical costs, and elevated mortality rates. Constant attempts have been made to discover newer and more effective antimicrobials to reduce the severity of antibiotic resistance. Plant secondary metabolites, such as essential oils, have been the major focus due to their complexity and bioactive nature. However, the underlying mechanism of their antimicrobial effect remains largely unknown. Understanding the antimicrobial mode of action of essential oils is crucial in developing potential strategies for the use of essential oils in a clinical setting. Recent advances in genomics and proteomics have enhanced our understanding of the antimicrobial mode of action of essential oils. We might well be at the dawn of completing a mystery on how essential oils carry out their antimicrobial activities. Therefore, an overview of essential oils with regard to their antimicrobial activities and mode of action is discussed in this review. Recent approaches used in identifying the antimicrobial mode of action of essential oils, specifically from the perspective of genomics and proteomics, are also synthesized. Based on the information gathered from this review, we offer recommendations for future strategies and prospects for the study of essential oils and their function as antimicrobials

Moisture sorption isotherm and thermal characteristics of freeze-dried tuna

Water activity is considered an important factor in assessing the stability of food. Understanding the relationship between water activity and equilibrium moisture content (moisture sorption isotherm) benefits food processing in terms of modeling of drying and estimation of shelf life. In addition, glass transition helps to quantify molecular mobility which helps in determining the stability of food. The aim of this study was to determine the moisture sorption isotherm and thermal characteristics of freeze-dried tuna. These characteristics will help in determining the monolayer moisture and glassy state of the product, at which food is considered most stable. Moisture sorption isotherm at 20°C and thermal characteristics (over a wide temperature range i.e. from -90 to 250 °C) of freeze-dried tuna flesh were measured. Isotherm data were modeled by BET (Brunauer-Emmett-Teller) and GAB (Guggenheim-Anderson–De Boer) models. The GAB and BET monolayer water values were determined as 0.052 and 0.089 g g-1 dry-solids (dry-basis), respectively. In the case of samples at moisture contents above 0.10 g g-1 (wet basis), DSC (Differential Scanning Calorimetry) thermograms showed two-step state changes (i.e. two glass transitions), one exothermic peak (i.e. molecular ordering) and another endothermic peak (i.e. solids-melting). However, the sample at moisture content of 0.046 g g-1 showed three-step state changes (i.e. three glass transitions). The multiple glass transition could be explained by the natural heterogeneity of tuna flesh and inhomogeneity due to molecular incompatibility of the different compositions. The moisture content did not affect the first glass transition temperature nor the exothermic peak (p>0.05), whereas the third glass transition temperature decreased (i.e. plasticized) with increasing moisture content (p<0.05). The solids-melting peak temperature decreased, and enthalpy increased with decreasing moisture content (p<0.05)

Disruption of KPC-producing Klebsiella pneumoniae membrane via induction of oxidative stress by cinnamon bark (Cinnamomum verum J. Presl) essential oil

Klebsiella pneumoniae (KP) remains the most prevalent nosocomial pathogen and carries the carbapenemase (KPC) gene which confers resistance towards carbapenem. Thus, it is necessary to discover novel antimicrobials to address the issue of antimicrobial resistance in such pathogens. Natural products such as essential oils are a promising source due to their complex composition. Essential oils have been shown to be effective against pathogens, but the overall mechanisms have yet to be fully explained. Understanding the molecular mechanisms of essential oil towards KPC-KP cells would provide a deeper understanding of their potential use in clinical settings. Therefore, we aimed to investigate the mode of action of essential oil against KPC-KP cells from a proteomic perspective by comparing the overall proteome profile of KPC-KP cells treated with cinnamon bark (Cinnamomum verum J. Presl) essential oil (CBO) at their sub-inhibitory concentration of 0.08% (v/v). A total of 384 proteins were successfully identified from the non-treated cells, whereas only 242 proteins were identified from the CBO-treated cells. Proteins were then categorized based on their biological processes, cellular components and molecular function prior to pathway analysis. Pathway analysis showed that CBO induced oxidative stress in the KPC-KP cells as indicated by the abundance of oxidative stress regulator proteins such as glycyl radical cofactor, catalase peroxidase and DNA mismatch repair protein. Oxidative stress is likely to oxidize and disrupt the bacterial membrane as shown by the loss of major membrane proteins. Several genes selected for qRT-PCR analysis validated the proteomic profile and were congruent with the proteomic abundance profiles. In conclusion, KPC-KP cells exposed to CBO undergo oxidative stress that eventually disrupts the bacterial membrane possibly via interaction with the phospholipid bilayer. Interestingly, several pathways involved in the bacterial membrane repair system were also affected by oxidative stress, contributing to the loss of cells viability

Assessment of personal hygiene knowledge, and practices in Al Ain, United Arab Emirates

a b s t r a c t There is little information available about incidences and causes of foodborne illnesses that can help the government develop policies, which prevent them in the UAE. This study includes a group of multinational subjects (males and females), residing in Al Ain, UAE, and of an age ranging between 15 and 55 years. A questionnaire designed to assess &quot;Knowledge&quot; and &quot;Practice&quot; of public hygiene measures was piloted in a group of subjects from the public (n ¼ 600). Data shows that 100% of highly educated subjects with postgraduate degrees (Master and PhD) have the proper information about food safety. However, only 70% of them always wash their hands before and after eating, while 80% always wash their hands after using toilets and frequently using warm water and soap. 29% of the total participants were inflicted with foodborne illness, and 85% read articles about food safety and personal hygiene. Most of the subjects in this study are Muslims, and they mainly depended on their daily attitude, which affects their personal hygiene because they must wash before praying. Data generally referred that awareness programs or training are needed, even for the highly educated members of the public. Further research is needed to explain the differences between reports of actual and usual behaviors

Cytotoxicity, antihypertensive, antidiabetic and antioxidant activities of solid-state fermented lupin, quinoa and wheat by Bifidobacterium species: In-vitro investigations

© 2018 Elsevier Ltd This study aimed to investigate the in-vitro cytotoxicity activity against two cancer cell lines, a-amylase and a-glucosidase inhibitions, ACE-inhibition, antioxidant and proteolytic activities of whole-grain lupin, quinoa and wheat fermented by three species of Bifidobacterium spp. B. animalis, B. breve and B. longum were employed in solid-state fermentation (SSF) 37 °C for 72 h. The ranges of total phenolic contents in fermented lupin (FL), quinoa (FQ) and wheat (FW) were ~17.0 to 44.0, ~11.0 to 36.0, ~5.0–29.0 mg GAE/g, respectively, relative to the unfermented control. a-Glucosidase inhibition increased significantly (p &lt; 0.05) in FL and FQ after 24 h of fermentation. The cereals fermented by B. breve and B. longum had markedly increased ACE-inhibition activities. The magnitude of the cytotoxicity activities in FL was greater (p &lt; 0.05) by approximately 5-fold and 3-fold against colon cancer cell (Caco-2) and breast cancer cell (MCF-7), respectively than in FQ and FW. The findings suggest that health properties of grains could be enhanced by probiotic fermentation and such enhancements depend on grain type and probiotic species. The inclusion of grains fermented by probiotics into foods could improve health benefits of these product

Middle Eastern plant extracts: an alternative to modern medicine problems

Middle Eastern countries are primarily known for their dry sand deserts; however, they have a wider physiographic range which includes upland plateau and mountain ranges. The Middle East is home to various types of plants, such as Phoenix dactylifera (date palm tree), Scrophularia striata (herbaceous plants), and Opuntia ficus-indica (cactus). These plants have been found to have various types of bioactivities, such as antimicrobial activities against both bacteria and fungi, in addition to exhibiting anti-inflammatory effects and anti-cancer characteristics which can be utilized in the clinical setting for treatment. Due to limited reviews focusing on plant extracts from the Middle East, we aim to provide a discourse on plants from this region which have various bioactivities and to provide information on the compounds that can be identified from these plants. This is to enhance our understanding to improve modern medicine problems such as antimicrobial resistance and to find an alternative cure for cancer. It is hoped that the collation of information from this review will enable an assessment of the direct role of Middle Eastern plants in providing therapeutic options to address the predicaments in the medical field