Modeling the Effect of Selected Microorganisms’ Exposure to Molasses’s High-Osmolality Environment
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Date
2023-01-16
Authors
Filipović, Vladimir
Lončar, Biljana
Kneživić, Violeta
Nićetin, Milica
Filipović, Jelena 
Petković, Marko
Journal Title
Journal ISSN
Volume Title
Publisher
Appleid Sciences
Abstract
: In this research series, several sugar beet molasses of different osmolalities were inoculated
with a mix of the following microorganisms, Escherichia coli, Salmonella spp. and Listeria monocytogenes,
to develop mathematical models and correlations of the effect of different levels of osmolality and
different exposure time to the viability of the selected microorganisms. The respective enumerations
of Escherichia coli, Salmonella spp., Listeria monocytogenes, Enterobacteriaceae, and total plate count
were conducted on inoculated molasses samples of different osmolalities (from 5500 to 7000 mmol/kg)
and at different exposure times (from 0 to 5 h). The results showed that by increasing molasses
osmolalities, all the selected microorganisms’ exposure time viability measures statistically decreased
significantly. Salmonella spp. showed the highest viability of all the tested microorganisms in a high
osmotic environment. In contrast, Listeria monocytogenes showed the least resilience to osmotic stress,
with a reduction in the numbers below the detection limit. The developed mathematical models
of microorganisms’ viability exposed to molasses’s high-osmolality environment were statistically
significant, allowing for the good prediction of a number of microorganisms based on exposure time
and osmolality levels. The obtained results describe molasses’s excellent microbial load-reducing
capability and provide the potential for applications in the production of safe foods.
Description
According to the presented results in this investigation, it can be concluded that the
numbers of the selected microorganisms inoculated to the molasses of different osmolalities
(from 5500 to 7000 mmol/kg) instantly significantly reduced. A prolonged exposure time
led to a statistically significant viability decrease in all the tested microorganisms, where
the rate of reduction decreased with time. Increasing molasses’ osmolality levels led to a
statistically significant decrease in viability for all the tested microorganisms. From all the
tested microorganisms, Salmonella spp. showed the highest viability, while L. monocytogenes
showed the least resilience to osmotic stress, with a reduction down to numbers below the
detection limit. The developed mathematical models were statistically significant, while the
predicted and observed responses had a good correlation, allowing for a good prediction of
the number of microorganisms based on the exposure time and osmolality levels. Further more, the correlation and principal component analysis results provided a visualization
of the negative correlation effects between the independent variables (exposure time and
osmolality level) and the viabilities of the selected microorganisms. The obtained results
describe molasses’ excellent microbial load-reducing capability and provide the potential
for applications in the production of safe foods
Keywords
sugar beet molasses, osmolality, Escherichia coli, Listeria monocytogenes, Salmonella spp