Byssochlamys nivea Growth in Papaya Juice as Influenced by Water Activity and Ascospore Age

In a previous study on Byssochlamys nivea growth in pineapple juice (Zimmermann et al., 2011a), the water activity (aw) was shown to be statistically significant (p<0.05) on growth parameters, while Ascospore Age (AA) did not influence the microorganism growth. Since the study of thermal resistant moulds is relevant to the industry and the medium composition has an important effect on the growth/inactivation of microorganisms, the evaluation of aw (0.90 to 0.99) and AA (30 to 90 days) influence on growth parameters of B. nivea in a different juice, papaya juice, is the main purpose of this study. Primary models were fitted to experimental data. The results showed that AA did not influence mould growth; nevertheless, aw was statistically significant for the parameters λ and μmax. These results confirm the previous study, concluding that the growth parameters of B. nivea were influenced by aw, irrespective of the kind of juice. Secondary models described the influence of the significant factor on the growth parameters. In an attempt to contribute to the food industry, the present study evaluated the growth of Byssochlamys nivea in papaya juice as influenced by water activity and ascospore age. The findings will be useful when developing strategies to prevent growth of B. nivea in acid fruit juice.