Avaliação da termorresistência de microrganismos formadores de esporos em preparados de fruta

  • Joana Isabel Carvalho Pinto (Student)

Student thesis: Master's Thesis


Increasingly, the primary goal of the agro-food industry is to ensure the food quality and safety of the commercialized products. Therefore, the search for methodologies that not only comply with the demands of the consumer but also with the high quality standards have been receiving special attention. These include thermal processing - such as pasteurization - whose challenge is to ally the maintenance of nutritional and organoleptic characteristics, as well as to ensure that the product does not pose a risk to the consumer’s health. In this perspective, the study of the time-temperature pasteurization binomials that should be applied in the food matrices in order to be increasingly aligned with the desired profile, is highlighted. Dried fruits, cereals and red fruits stand out among the food matrices considered to be the most critical given their predisposition for microbial contamination. In this angle, FRULACT - a company in constant evolution of knowledge in all operational areas, from manufacturing to commercialization - bets on research to support the processes employed. The aim of this study was to characterize the microbiological load of raw materials of interest. In the process, the goal was also to optimize the time-temperature pasteurization binomials, taking into account the impact of the conditions of the production process, namely the inactivation of the microbiological load. Thus, six preparations (based on the selected raw materials - cereals, wild fruits, strawberry, dietetic strawberry, dried prune and dietetic dried prune) were selected and submitted to four simulations of distinct time-temperature binomials, followed by the simulation of three different pasteurization conditions (85°C/5min, 85°C/10min and 90°C/5min). In conclusion, the pasteurization time-temperature binomial is chosen according to the associated conditions of ingredients mixing. In general terms, temperatures above 40°C together with periods of time greater than 2 hours should be taken in consideration. In these conditions there is an increase in thermoresistance associated with spore-forming bacteria, which are able to remain viable when exposed to a heat treatment of 90°C/5min.
Date of Award1 Aug 2017
Original languagePortuguese
Awarding Institution
  • Universidade Católica Portuguesa
SupervisorCristina Martins Rodrigues (Supervisor)


  • Mestrado em Engenharia Alimentar

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