Karl R. Matthews, Ph. D.

 

Research Interest

The microbial safety of food impacts consumers nationally and internationally. More so than many other disciplines food microbiology is in continual flux; new pathogens emerge, long recognized pathogens re-emerge as problems, and consumer demands change. My research focuses on enhancing the microbial safety of food to improve human health.

Antimicrobial treatments using light and plant derived compounds.

Food safety is a global issue with significant implications for human health. The World Health Organization reports that unsafe food results annually in the illnesses of at least 2 billion people worldwide with many thousands of deaths. Chemical methods used to disinfect food may protect against the spread of foodborne bacteria, but such practices may place selective pressure on bacteria to develop countermeasures that are often heritable. Consumers in Europe and Britain are concerned that the use of chemical agents creates both microbiological and chemical food safety hazards by selecting for antibiotic resistance and generating potential carcinogenic compounds. The research conducted by the Matthews’ laboratory will provide the proof of concept for the photoinactivation treatment of meat and poultry, fruits and vegetables to control foodborne bacteria and enhance microbial safety. The photosensitizers used will be natural compounds that will be acceptable by consumers (provide a “clean label”) and government regulatory agencies and are not known to be associated with contributing to antimicrobial resistance. The umbrella goal of the research is to provide the science to support the effective application of photoinactivation treatment of food derived from animals and plants to improve microbiological safety of those foods.

Antibiotic residues, antibiotic resistance bacteria and antibiotic resistance genes in vegetable crops and production environments.

Antimicrobial resistant (AMR) bacteria are a global health emergency. Reports from various agencies including, the CDC, WHO, FAO, and EFSA reach similar conclusions that antibiotic usage in agriculture enhances the spread of AMR bacteria. The use of antibiotics in crop production is often overlooked when considering the spread of AMR bacteria. Viable AMR bacteria can be found in raw agricultural commodities (Fresh and fresh-cut fruits and vegetables) and ready-to-eat (RTE) foods that have been minimally processed. Given the global marketplace, fresh and RTE fruits and vegetables serve as ideal vectors for the spread of AMR bacteria. My research provides the unique opportunity to explore the risks associated with application of antibiotics to crops through international collaborations. Antibiotics sprayed on crops intended for direct human consumption may include amoxicillin, streptomycin, tetracycline, and penicillin. Antibiotic residues, presence and prevalence of antibiotic resistance bacteria and associated antibiotic resistance genes is of concern. Research is being conducted to develop cost effective methods that can be used globally, particularly in developing countries to remove or inactivate antibiotic residues that may be found on food crops.