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Advisor(s)
Abstract(s)
Heat processing is the most commonly used treatment for microbial inactivation. However, temperature may
have adverse effects on sensory and nutritional attributes of foods. Non-thermal technologies have received
increasing attention for preservation of beverages, due to their potential for inactivating spoilage and
pathogenic microorganisms. In addition, they can help minimizing quality losses, namely flavour, colour and
nutritional value. Ultraviolet-C radiation (UV-C) is widely used as an alternative strategy to control
microorganism in food products. Alicyclobacillus acidoterrestris is a thermo-acidophilic, non-pathogenic and
spore-forming bacterium, able to grow at low pH (3.0–3.5) and high temperatures (50–70 °C). It has been
considered a new type of spoilage bacterium, with important potential spoilage concern for hot-fill fruit and
fruit juices. The main objective of this work was to study the influence of UV-C radiation treatments with
seven different intensities (0.32, 0.86, 2.59, 5.59, 8.45, 11.50 and 13.44 W/m2) on A. acidoterrestris
inactivation in apple juices. Commercial juices were artificially inoculated with bacterium, with initial loads
around 107 CFU/mL. They were then exposed to UV-C radiation and the treatment impact on microbial loads
was assessed throughout exposure times. Results showed that the log-survival of A. acidoterrestris decreased
linearly with treatment time, for all intensities tested. A decimal reduction time at a given UV-C intensity was
estimated by fitting a first order kinetic model to experimental data. When the most severe intensity was
used (i.e., 13.44 W/m2), the number of spores decreased drastically (around 5-log reduction, which attains
US Food and Drug Administration requirements) after 8 min of treatment. For the remaining UV-C intensities, this inactivation was achieved for higher exposure times. Overall it can be concluded that UV-C radiation is a promising treatment with a drastic impact on the loads of A. acidoterrestris in apple juices, especially when high intensities are used.
Description
Keywords
Ultraviolet-C radiation Apple juices Alicyclobacillus acidoterrestris Inactivation
Pedagogical Context
Citation
TREMANIN, Andreia ; BRANDÃO, Teresa R. S. ; SILVA, Cristina L. M. - Inactivation of Alicyclobacillu acidoterrestris in apple juice under ultraviolet irradiation treatments. In 29th EFFoST Conference - Food Science Research and Innovation: Delivering Sustainable Solutions to the Global Economy and Society, Athens, Greece, 10-12 November 2015. DERMESONLOUOGLOU, Efimia …[et al.] (ed.) - Proceedings 29th EFFoST Conference. Athens: NTUA, School of Chemical Engineering, 2015. ISBN 978-618-82196-1-8. Vol. 1, p. 159-163