Enhancing the Microbiological Safety of Fresh-Cut Produce and Unpasteurized Juice with Tropical Fruit Extracts

Non-Technical Summary:<br/>
Consumption of fresh-cut fruits and vegetables has been made roughly a 10% annual increase since 1995 and the revenue is estimated at $10-12 billion every year in the United States. While these food products offer consumers great flavor, nutritional value, and convenience, they are predisposed to microbial contamination. Pathogenic organisms may get into fresh produce and grow rapidly on the cut where juices and nutrients are easily available. Thus microbiological safety is a potential health issue since fresh-cut produce is often eaten raw. There has been a number of high-profile foodborne illness outbreaks associated with the consumption of fruits and vegetables. Moreover, unpasteurized juice poses another food safety concern. Although the risk of infection by harmful bacteria such as Salmonella, Escherichia coli O157:H7 and Listeria monocytogenes as a result of drinking unpasteurized juice is considered to be low, the health consequence of infection can be severe. Practical interventions that can eliminate or control pathogenic bacteria in fresh-cut produce and unpasteurized juice are urgently needed. The long-term goal of our research is to enhance produce safety practices from field to table. This project aims to explore the antimicrobial potential of six tropical fruits and investigate their applicability to fresh-cut produce and unpasteurized juice. If successful, extracts from selected tropical fruits may be used as natural preservatives and provide a simple, cost-effective, and green solution to enhancing the microbiological safety of food. They would help boost consumer confidence in produce and juice as safe foods.
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Approach:<br/>
Guava, noni, passion fruit, lemon, lime, and java plum will be obtained from local farms and grocery stores. Juices will be squeezed from these tropical fruits. Moreover the resulting peels and pulps will be dried under ambient conditions, powdered, and extracted with solvents having different polarity. The agar well diffusion method will be used to determine the antimicrobial potential of various extracts from the tropical fruits against Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes. Based on agar well diffusion assay results, serial dilutions of the tropical fruit extracts showing large inhibition zones will be made and tested further to determine the minimum lethal concentration against each bacterial strain in water and nutrient-rich broth. The efficacy of extracts from selected tropical fruits for controlling the three pathogenic bacteria in unpasteurized apple and orange juices, fresh-cut papaya, cantaloupe, and lettuce, as well as alfalfa sprouts will be determined. Treated food samples will be incubated at 7 degree Celsius for up to 12 days. The pathogenic bacteria and indigenous microorganisms in the food will be enumerated on pathogen-specific and nonselective agar media, respectively.