Andrea Gilbert

Participant: PROMISE AGEP Research Symposium

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Andrea Gilbert

Department: Nutrition and Food Science

Institution: University of Maryland College Park (UMD)

ABSTRACT

Photoirradiated Caffeic Acid as an Antimicrobial Treatment for water and fresh-produce

Ensuring the safety of fresh produce is a major challenge in the food industry. To achieve this, produce is typically washed with sanitizer solutions such as chlorine and organic acids, albeit, with limited efficacy. Therefore, there is need for limiting the load of pathogenic bacteria prior to harvest. We are investigating a new antimicrobial treatment based on a food-grade compound, caffeic acid (CA), used in conjunction with 400 nm visible light.

The antimicrobial efficacy of the treatment was evaluated against gram positive and gram negative bacteria using a 28 bulb LED array that emitted 400 nm light. Experiments were performed in solution (5 log CFU/mL) as well as on spinach leaves (4 log CFU/mL). Experiments were also performed in presence of DMSO (Dimethyl sulfoxide) and phosphate buffer saline (PBS, pH 6.7) to help determine the mechanism of the antimicrobial effect on bacteria.

The combined treatment was more effective on Escherichia coli H157:07, the model gram-negative bacteria, showing a 4 log CFU/mL reduction in solution after two hours. A 3 log CFU/mL reduction in E. Coli was observed in whole leaf spinach after 60 minute of exposure to CA. Interestingly, blue light did not accelerate the rate of inactivation on spinach. The addition of DMSO did not decrease the efficacy of the combined treatment, however, the antimicrobial effect was attenuated in presence of PBS. With optimization, caffeic acid with blue light can be a highly effective antimicrobial treatment for fresh produce in both pre-harvest and post-harvest applications.

BIOGRAPHICAL SKETCH

Andrea Gilbert graduated from the University of Maryland in 2014 with a bachelor’s of science in Nutrition and Food Science. Originally planning to study dietetics, she took culinary arts vocational classes and competed in a national competition prior to attending UMD. Upon graduation, she worked in quality assurance in the baked goods industry gaining valuable experience in food processing. She returned UMD in 2016 to begin her graduate studies in Food Science under Dr. Rohan Tikekar. Her research revolves around non-thermal antimicrobial processing that can be used to improve the safety of fresh produce as well as food contact surfaces. She has presented her research at the 2016 Conference of Food Engineering in Columbus, Ohio as well as at the 9^th Mini Summit on Food Safety, Policy and Sustainability at Shanghai Ocean University.