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The temperature effect on the interaction between fungal isolates of papaya was studied. Rhizopus stolonifer, Colletotrichum cobbittiense, Fusarium pernambucarum, and Alternaria arborescens were grown in papaya agar in pairs, one against the other, at 13, 25, and 35 °C. The growth rate for each fungus was compared when grown alone or paired. Four types of interaction were observed: mutual intermingling, mutual antagonism on contact, dominance on contact, and dominance at a distance. At 13 and 35 °C, F. pernambucarum was more competitive whereas at 25 °C R. stolonifer does. In vivo validation showed R. stolonifer was the dominant fungus at 25 °C but coexists with C. cobbittiense forming a second infection. Then, a hierarchy may be established through a growth mechanism to infer which fungi may develop first and damage fruit to prevent postharvest losses. These findings could improve the management of papaya fruit in the postharvest stage. Several species of fungi are responsible for postharvest diseases in papaya. Diseases development depends on environmental and fruit physiological conditions. One species may dominate or inhibit other's or can coexist as well. Interactions between pathogenic fungi may be considered to infer fungi development. These results may help us to improve the postharvest treatment of papaya. [ABSTRACT FROM AUTHOR]

Colletotrichum species are the most important postharvest spoilage fungi of papaya fruit. The objective of this research was to evaluate the effect of temperature and relative humidity on growth rate and time for growth to become visible of five strains of Colletotrichum gloeosporioides isolated from papaya fruit in a complex medium. As a primary model, the radial growth rates were estimated using the Baranyi and Roberts model in papaya agar. The Solver MS Excel function was used to obtain the time to visible mycelium (tv). Secondary models obtained with the Rosso et al. cardinal model of inflection were applied to describe the effect of temperature on the growth rate (μ). The Arrhenius-Davey model was used to model tv. The obtained models seem to be satisfactory for describing both μ and tv. The relative humidity had an effect on μ and tv for all tested C. gloeosporioides isolates, but no model accurately described the behavior of the fungus. External validation of models was performed with papaya fruit. Growth models were developed with the same models used in vitro. The bias and the accuracy factors as indices for performance evaluation of predictive models in food microbiology as a function of temperature and RH were 1.22 and 1.33, respectively, for μ and 1.18 and 1.62, respectively, for tv, indicating accurate predictions. The supply chain of papaya is complex and requires constant conditions, and poor conditions can result in damage to the fruit. Knowledge of the behavior of C. gloeosporioides on papaya fruit and application of the developed models in the supply chain will help to establish transport control strategies to combat these fungi. This research has contributed to development of the first models of growth for C. gloeosporioides in Mexico. Temperature greatly affected fungal rot of papaya at the postharvest stage. Fungal growth occurred when water was available, regardless of the relative humidity. Predictive models may help food processors make decisions for suboptimal supply chains. [ABSTRACT FROM AUTHOR]