Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 9, 1999
Publication Date: N/A
Interpretive Summary: Fresh-cut produce is a newly emerging but rapidly developing industry which offers the consumer both convenient and nutritious food. Along with the development of this industry, new problems may arise in the food safety area. There is very little knowledge concerning the microbial contamination of fresh-cut fruits and vegetables. This is especially true of fresh-cut fruit, which hasn't developed as quickly as fresh-cut vegetables. Therefore, it is necessary to obtain information on the fate and control of foodborne pathogens on fresh-cut fruit. Listeria monocytogenes is a bacterium that has been associated with a number of outbreaks of the foodborne illness called listeriosis in recent years. Our research has shown that this bacterium can survive and increase in population on apple fruit slices when fruit are stored at 20 or 10C but cannot multiply when grown at 5C. Populations of the bacterium inoculated into decayed apple tissue increased on apple fruit decayed by Glomerella cingulata. Therefore, proper storage temperature, as well as the absence of postharvest pathogens such as Glomerella cingulata, is important for maintaining the safety of fresh-cut apples. This information will be useful to the fresh-cut fruit industry in reducing potential health hazards.
The food-borne pathogen Listeria monocytogenes survived and its populations increased on 'Delicious' apple slices at 10 or 20 C in air or controlled atmosphere (CA) of 0.5% O2-15% CO2 but did not grow at 5 C. CA had no significant effect on the survival or growth of L. monocytogenes. The pathogen populations declined over time when grown in various concentrations of apple juice and the decline was greater as the concentration of the juice decreased. Populations of L. monocytogenes inoculated into decayed apple tissue, continually increased on fruit decayed by Glomerella cingulata (Stoneman) Spaulding et Schrenk, but did not survive after 5 days on fruit decayed by Penicillium expansum Link. The pH of the decayed area declined from pH 4.7 to 3.7 in the case of P. expansum, but in the case of G. cingulata the pH increased from pH 4.7 to 7.0. This pH modification may be responsible for affecting the growth of the food-borne pathogen. The storage temperature, as well as the absence of postharvest pathogens like G. cingulata, is critical for maintaining the safety of fresh-cut apples.