Modelling the effects of local food spices on the growth of Escherichia coli 0157:H7 and Campylobacter sp.
Date
2018-11
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Federal University of Technology, Owerri
Abstract
The activity of food spices (pepper, ginger and salt) were investigated for their ability of inhibit or stimulate the growth of Campylobacter jejuni and Escherichia coli 0157:H7, isolated from meat and coleslaw samples, in singles and in combination. In addition, the isolates were subjected to temperature dependent inactivation for the development of primary models using the GinaFit Software. A 2 k Factorial plot was carried out to determine the single and combined effect of the spices on the test isolates. Results shows that at a concentration of 800 µg/ml, ginger extracts had stationary/inhibitory effect and pepper had inhibitory effects while salt also had inhibitory effects at 4% concentration. At 8% concentration, results indicated a bactericidal effect as the mean growth declined rapidly below the initial bacterial population. Similar results was also recorded for ginger at 120µg/ml. However, pepper had stimulatory effect on Campylobacter jejuni. On the other hand, results on Escherichia coli 0157:H7 shows that the pepper extracts had mean stimulatory effect at 400 µg/ml, while the salt extracts had similar results at 4% salt concentration. Mean inhibitory effect was obtained for ginger extracts at 400 µg/ml and 800 µg/ml but, stimulatory at 1200 µg/ml. Also, at a concentration of 800 µg/ml, pepper extracts had inhibitory effects, while salt solution also had stimulatory effects at 8% concentration. At 12% salt concentration, the effect on mean growth was bactericidal demonstrated by rapid decline below the initial bacterial population. GINAFIT Models were used to determine values of “Α, δ1, Ρ, Log N, Kmax, R2 , MSE” which were adopted for model development. Findings had it that at -4 and 4 degrees, the isolates was inactivated. In addition, Campylobacter jejuni tested grew at 25 and 35 degrees while Escherichia coli grew at 25, 35 and 45 degrees but inactivated at -4 degrees.
Description
This thesis is for the award of Master of Science (MSc.) in Food and Industrial Microbiology
Keywords
Inactivation, modelling, spices, factorials, Escherichia coli, Department of Microbiology, Campylobacter sp.
Citation
Adeleye, S. A. (2018). Modelling the effects of local food spices on the growth of Escherichia coli 0157:H7 and Campylobacter sp. [Unpublished Master's Thesis]. Federal University of Technology, Owerri, Nigeria