Modelling the effect of the redox potential and pH of heating media onListeria monocytogenesheat resistance

Abstract

The obtained model shows the action of redox potential on L. monocytogenes thermal destruction and might be useful to take into account in food thermal processes.

Growth and reducing capacity of Listeria monocytogenes under different initial redox potential

“…In addition to these observations, our study marked that the L. monocytogenes was able to grow hardly affected in a wide range of external redox potentials. Because we had observed in our previous study that L. monocytogenes thermal destruction was dependent on the external redox potential (Ignatova et al. 2008), a strong redox impact on L. monocytogenes growth was expected.…”

“…The unfavourable action of low redox potential was observed in other works. In our previous study dealing with redox action on L. monocytogenes heat resistance, we observed that the lower redox was, the better was thermal inactivation (Ignatova et al. 2008).…”

“…The article also points out information about reducing capacities of one of the major concerns in food industry – L. monocytogenes . In our previous study, we reported that oxidizing conditions of heating media significantly increased L. monocytogenes heat resistance (Ignatova et al. 2008).…”

Towards a maximal cell survival in convective thermal drying processes

“…Firstly, although a model with interpretable parameters and explainable mechanisms is preferred, empirical models can also provide an accurate description of the changing history of cell numbers (Chen, 2007;Geeraerd et al, 2000;Xiong, Xie, Edmondson, Linton, & Sheard, 1999). Secondly, environmental parameters such as water activity (Coroller et al, 2001;Fernandez et al, 2007), pH (Cameron, Leonard, & Barrett, 1980;Hassani, Alvarez, Raso, Condon, & Pagan, 2005) and redox potential (Abraham, Debray, Candau, & Piar, 1990;Ignatova, Leguerinel, Guilbot, Prevost, & Guillou, 2008;Reichart, 2001) considerably affect the inactivation kinetics. Finally, an increasing number of studies have suggested that the physical kinetics of heat and mass transfer should be considered for the modeling of both microbial growth and inactivation (Amezquita, Weller, Wang, Thippareddi, & Burson, 2005;Mafart, 2005), which appears to be paramount for a drying process which involves significant heat and mass transfer.…”

Contribution of exofacial thiol groups in the reducing activity of Lactococcus lactis

“…Nevertheless, oxygen disruption by L. lactis cannot explain the decrease in E h from oxidant to reducing values. Removing oxygen from a liquid media using nitrogen gas does not decrease the E h to reducing values [4,18]. According to the Nernst equation, E h is decreased by 59 mV for one log of oxygen concentration, and it is generally observed that degassing the medium only decreases the E h by 100–150 mV.…”