The inactivation of Listeriamonocytogenes in a kiwifruit puree by conventional and microwave heatingwas studied.
Survival curves at three microwave power levels (600–1000 W) and three temperatures (50–60 °C) were
obtained. Data were properly fitted by a first-order kinetic model. Processing times under both technologies
were corrected to isothermal treatment for the kinetic study. Microwave heating was shown to effectively inactivate
L. monocytogenes. In the range of microwave and conventional processing conditions assayed, the 5-log10
reductions of L. monocytogenes recommended by the FDA for pasteurized products were achieved. The level of
microwave power applied had a considerable influence on the L. monocytogenes inactivation rate. The higher
the power level, the faster the inactivation. The inactivation of L. monocytogenes under microwave heating at
900W(D60 °C= 17.35 s) and 1000W(D60 °C= 17.04 s) happened faster than in a conventional thermal process
(D60 °C= 37.45 s). Consequently, microwave heating showed greater effectiveness for L.monocytogenes inactivation
than conventional heating.
Industrial relevance: Consumers' desires are oriented towards newfoods that are convenient, easy to preserve and
ready-to-eat products, being consumption of fresh fruit replaced with processed fruit products. Food industry is
currently focused on the development of novel and minimally processed products with improved quality. Thus, a
variety of newprocessing technologies are being explored as alternative to traditional thermal processing. In this
work, the thermal and microwave inactivation kinetics of Listeriamonocytogenes in a ready-to-eat kiwifruit puree
were investigated so as to assess the suitability of microwave processing as an alternative to thermal processing.
The results of this study point out that more than conventional heating, microwave technology can be an appropriate
means of fruit product pasteurization with the possibility of offering the required safety by using a lower
process time, when microwave power of a certain level is applied.