Protecting Our Food and Health Against Microbial Contamination and Infection

NON-TECHNICAL SUMMARY: Microbial food safety is very important to modern food science and human beings due to outbreaks of foodborne infections and intoxications. Therefore, the emphasis of the proposed research is protecting human heath against food poisoning and bacterial infection. Control of foodborne pathogens and the reduction in the potential health risks to consumers from pathogens is one of the most urgent problems confronting the food industry. Chemical agents with antimicrobial activity have been used as one of the most traditional techniques. However, consumers today are increasingly concerned about the safety of these chemical additives in foods and prefer natural, healthy, and unadulterated foods. Consequently, many researchers are searching for naturally occurring antimicrobial compounds from sources such as fruit, plants and herbs. The first section of this project is to focus on characterization of functional ingredients from natural fruit and plants. Antimicrobial mechanisms of action of bioactive compounds on cellular and molecular levels against human pathogens will be studied. The P.I.~{!/~}s research in utilizing cranberries to protect human against food poisoning has attracted significant attentions from the public. Mechanisms of antimicrobial activities in natural ingredients remain to be studied further, so a particular antimicrobial manipulation using natural antimicrobial compounds for a specific pathogen can be developed. In this project, the antimicrobial effects of natural compounds from fruit such as berries on cellular structure and gene expression of pathogens will be evaluated. The study on antimicrobial mechanisms of natural compounds (cellular structure and gene expression) can help to elucidate cells~{!/~} responses to the antimicrobial compounds and eventually be beneficial for designs of specific method using specific natural compounds for controlling a specific type of microorganisms. With the increase in reports of foodborne infections, great attention has been given to the development of new/improved methods for rapid detecting microbial pathogens. Although methods such as microbial culturing and biochemical assays have proven to be useful in quality control, they still cannot meet all the demands from the food industry because of their intrinsic limitations. The second section of this project is to focus on the development of more effective rapid methods to detect and control bacterial pathogens in/on foods before these foods are released for sale with the goal of reducing foodborne illnesses. The P.I. will develop biosensors and food defense technologies for early detection, enumeration, identification, and characterization of bio-weapons in the environment, agriculture, and food. The field is critical to the human health, safety, and security of the USA in terms of bio-security, environmental safety, food safety, and related areas. We expect the well-being of the people of Maine will have safer food supply and be protected against foodborne illness and bacterial infection by the completion of the project.<P>

APPROACH: The first objective will be conducted first followed by the second objective. I. Characteristics and mechanisms of action of natural ingredients for protecting human health against food poisoning and bacterial infection We will study the eucidation of antimicrobial mechanism, of American cranberry, Vaccinium macroparpon, against foodborne pathogens. Then we will investigate possible applications of berries in food products. We will also study the inhibition of Helicobacter pylori by Maine wild blueberry phenolics. II. Development of novel technologies to detect and eliminate microbiological hazards We will develop an efficient, sensitive, and applicable protocol to detect pathogens by gold nanoparticle sandwich hybridization methods and real-time detection of viable foodborne pathogens by a piezoelectric biosensor. We will also develop a novel, simple, inexpensive, instrument-free gaseous ClO2 approach for disinfection of fresh produce. All experiments will be repeated three times. Bacterial numbers will be converted to log10 CFU/ml. All data will be averages of three replications and the numbers will be statistically analyzed. The experimental design will be Randomized Complete Blocks (RCB). Analysis of variance (ANOVA) will be performed on cell counts using the SAS General Linear Models procedure. Means of three replicates will be plotted in graphs, and significant differences determined at the 95% confidence limit. Differences among treatments (pairwise comparison) will be evaluated by the Least Square Difference (LSD) test.