Fate of Escherichia coli O157:H7 and Salmonella spp. on fresh and frozen cut mangoes and papayas.

Escherichia coli O157:H7 and Salmonella infections have been associated with consumption of a number of fruits and vegetables. Although the fate of E. coli O157:H7 and Salmonella on many of these products is well studied, little is known about their behavior on cut mango and papaya. Mangoes and papayas have been associated with four and two documented outbreaks of salmonellosis, respectively. The objective of this study was to evaluate the fate of E. coli O157:H7 and Salmonella on fresh (4 degrees C, 12 degrees C and 23 degrees C) and frozen (-20 degrees C) cut mangoes and papayas. Cut mangoes and papayas were spot inoculated with either a four-strain or five-strain cocktail of E. coli O157:H7 or Salmonella, respectively. Inoculated samples were air dried, placed in containers and stored at 4+/-2, 12+/-2, 23+/-2 and -20+/-2 degrees C. Samples were enumerated following stomaching on nonselective and selective media at days 0, 1, 3, 5, 7, 10, 14, 21 and 28 (4+/-2 and 12+/-2 degrees C); 0, 1, 3, 5 and 7 (23+/-2 degrees C); and 0, 7, 14, 21, 28, 60, 90, 120, 150 and 180 (-20+/-2 degrees C). Population levels (log CFU/g) of fruit were calculated. E. coli O157:H7 and Salmonella have the potential to grow on temperature-abused fresh cut mangoes and papayas held at 23 degrees C. At 12 degrees C, Salmonella populations can grow on cut mangoes and papayas, however E. coli O157:H7 populations only grew on papayas. E. coli O157:H7 and Salmonella survived for 28 days, at 4 degrees C, on refrigerated mangoes and papayas. E. coli O157:H7 and Salmonella can survive on frozen cut mangoes and papayas for at least 180 days. Fresh and frozen cut mangoes and papayas are potential vectors for E. coli O157:H7 and Salmonella transmission.