Evidence of Salmonella internalization into fresh mangos during simulated postharvest insect disinfestation procedures.
Penteado A. L., Eblen B. S., Miller A. J.
Author Affiliation: Departamento de Tecnologia de Alimentos, Faculdade de Engenharia de Alimentos, Universidade Estadual de Campinas, Cidade Universitária, Zeferino Vaz, Caixa Postal 6121, Campinas, São Paulo, Brazil.
Journal of Food Protection 67 : 181-184
Abstract : A recent salmonellosis outbreak in USA was epidemiologically associated with consumption of imported fresh mangoes. Studies were conducted to simulate the commercial heat disinfestation method used to eliminate tephritid fly larvae from mangoes, as well as subsequent product cooling procedures, to assess whether this process promotes internalization of Salmonella into mangoes. The experimental parameters were chosen to mimic the disinfestation method used by the South American producer/packer implicated in the recent outbreak. Untreated domestically grown immature and ripened Tommy Atkins mangoes were immersed in water at 47°C for 90 minutes and then immersed in 21°C water containing brilliant blue FD and C no. 1 dye for 10 minutes. After dye internalization potential was established (67%), the same experiment was performed using 21°C water containing 107 CFU/ml Salmonella enteritidis expressing constitutive green fluorescent protein. Fruit was then stored at 10, 20, or 30°C for up to 1 week. Immature and ripened mangoes were positive for Salmonella internalization at a frequency of 80 and 87%, respectively. Internalization frequency into the stem-end segment (83%) was significantly higher (P0.05) than internalization into the middle-side (19%) or blossom-end (9%) segments of the fruit. Salmonella was detected in the mango pulp after 1 week of incubation. The degree of fruit ripeness, posttreatment holding temperature, or duration of storage had no significant effect (P>0.05) on internalization frequency or survival of Salmonella inside mangoes. This study illustrates the high potential for pathogen internalization if heat-disinfected mangoes are cooled using contaminated water.