RESUMO
This study aimed to evaluate the effectiveness of using two ozone applications (gaseous and mist) as a disinfection method for fresh persimmon. To test these sanitizers, in vitro and in vivo assays were performed, and the Escherichia coli was selected because it is a pathogen that causes foodborne diseases in humans. For in vitro experiments, a plate was inoculated with Escherichia coli strain ATCC 25922 and treated. For in vivo assays, persimmon fruit surface was inoculated with the bacteria and treated. For both assays, it was used 10,15,20,30,40 and 50 µL L-1 of gaseous ozone or ozonized mist for five minutes. The results demonstrated that the gas ozone application significantly reduced the growth of E. coli on the plate surface in vitro at doses of 30, 40 and 50 µL L-1 (with 0.83, 0.89 and 0.95 log CFU mL-1, respectively). The application of ozonized mist showed a significant reduction for 50 µL L-1 (with 1.28 log CFU g-1). And, for the in vivo assays, ozonized mist significantly reduced the number of bacteria on the persimmon surface, with a 1.57 log reduction, which was the largest for 40 µL L-1. Therefore, it is possible to conclude that the ozone application can contribute to the control of microorganisms present on fruit surfaces.
Assuntos
Diospyros , Desinfecção , Escherichia coli , Ozônio , Ozônio/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Diospyros/microbiologia , Desinfecção/métodos , Frutas/microbiologia , Desinfetantes/farmacologiaRESUMO
The incidence of Listeria monocytogenes on persimmon (Diospyros kaki) surface of 'Fuyu' and 'Rama Forte' was evaluated during a 5-month-period (from March to July) of two seasons periods (years 2005 and 2006). The fruits were collected in wholesale and street markets and retail in Sao Paulo and Campinas City, Brazil. A total of 582 fruits were analyzed using the Bax System which is based on the Polymerase Chain Reaction. The ability of this pathogen to grow on the peel and pulp of the two persimmon varieties was also verified at different incubation periods at the temperatures of 10, 20 and 30 degrees C. The growth parameters were obtained by modeling the experimental data using the Gompertz function. The incidence survey showed the absence of L. monocytogenes. The growth curves showed that L. monocytogenes can grow on the peel as well as in the pulp of the two persimmon varieties studied incubated at 10, 20 and 30 degrees C and that low temperatures can reduce the generation rate but does not inhibit its growth.