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Research Publications (Applied Sciences)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/213

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Author: search.filters.author.Ijabadeniyi, Oluwatosin AdemolaHas files: Yes

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    Inactivation of heat adapted and chlorine adapted Listeria monocytogenes ATCC 7644 on tomatoes using sodium dodecyl sulphate, levulinic acid and sodium hypochlorite solution
    (PAGEpress, 2017-04) Ijabadeniyi, Oluwatosin Ademola; Mnyandu, Elizabeth
    The effectiveness of sodium dodecyl sulphate (SDS), sodium hypochlorite solution and levulinic acid in reducing the survival of heat adapted and chlorine adapted Listeria monocytogenes ATCC 7644 was evaluated. The results against heat adapted L. monocytognes revealed that sodium hypochlorite solution was the least effective, achieving log reduction of 2.75, 2.94 and 3.97 log CFU/mL for 1, 3 e and 5 minutes, respectively. SDS was able to achieve 8 log reduction for both heat adapted and chlorine adapted bacteria. When used against chlorine adapted L. monocytogenes sodium hypochlorite solution achieved log reduction of 2.76, 2.93 and 3.65 log CFU/mL for 1, 3 and 5 minutes, respectively. Using levulinic acid on heat adapted bacteria achieved log reduction of 3.07, 2.78 and 4.97 log CFU/mL for 1, 3, 5 minutes, respectively. On chlorine adapted bacteria levulinic acid achieved log reduction of 2.77, 3.07 and 5.21 log CFU/mL for 1, 3 and 5 minutes, respectively. Using a mixture of 0.05% SDS and 0.5% o levulinic acid on heat adapted bacteria achieved log reduction of 3.13, 3.32 and 4.79 log CFU/mL for 1, 3 and 5 minutes while on chlorine adapted bacteria it achieved 3.20, 3.33 and 5.66 log CFU/mL, respectively. Increasing contact time also increased log reduction for both test pathogens. A storage period of up to 72 hours resulted in progressive log reduction for both test pathogens. Results also revealed that there was a significant difference (P ≤ 0.05) between contact times, storage times and sanitizers. Findings from this study can be used to select suitable sanitizers and contact times for heat adapted and chlorine adapted L. monocytogenes in the fresh produce industry.
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    Physicochemical properties of honey samples from Ondo state, Nigeria, and their bioactivity against spoilage and pathogenic organisms
    (WFL Publisher, 2014) Omoya, Funmilola Oluyemi; Ijabadeniyi, Oluwatosin Ademola; Ogonnoh, Olayemi Bosede
    Honey can be defined as the natural sweet substance produced by honeybees (Apis mellifera) from the nectar of blossoms or from the secretion of living parts of plant or plant sucking insects living on parts of plants. The medicinal property of honey has been an area of interest to researchers in recent times. This study focused on assessing the physicochemical components of honey samples and their bioactivity on some food spoilage organisms. One hundred samples of honey were collected from different locations in Ondo state, Nigeria. Their physicochemical components which include conductivity, ash content, moisture content, pH, mineral contents and colour were determined. There was variation in the physicochemical components of some of the honey samples with reference to international standards. The assessment of the honey samples as an antibacterial agent revealed it inhibitory potency on both bacteria and fungi isolated from food sample. The inhibitory effect was compared with that of standard antibiotic. The honey samples were seen to display a higher inhibitory effect on the tested organisms than the employed antibiotic.
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    Biocontrol of Listeria monocytogenes ATCC 7644 in fresh tomato with Probiotics
    (MN Khan, 2014-10) Ijabadeniyi, Oluwatosin Ademola; Naidoo, Shanice
    The effectiveness of probiotics Lactobacillus bulgarius and Streptococcus salivarius as biocontrol agents against Listeria monocytogenes ATCC 7644 in fresh tomato throughout storage and their effect on the physicochemical properties of tomato was evaluated. Tomato samples were cut into wedges and inoculated with 108 CFU/ml of Listeria monocytogenes ATCC 7644, thereafter inoculated with L.bulgaricus and S.salivarius separately. Tomato was also inoculated with probiotics L.bulgaricus and S.salivarius without inoculation of L.monocytogenes. Nutrient broth was prepared and inoculated with 108 CFU/ml of L.monocytogenes ATCC 7644 and thereafter inoculated with L.bulgaricus and S.salivarius separately after which all treatments were stored at 4°C for 72 hours. Chlorine was used as a control and compared against probiotics. L. monocytogenes counts taken during storage period in nutrient broth showed that L. bulgaricus had a 2.19 log reduction and S. salivarius had a 1.65 log reduction. The tomato study showed that L. bulgaricus had a 3.15 log reduction and S.salivarius had a 3.01 log reduction. Physicochemical properties of tomato were not affected (p > 0.05) by treatment with probiotics when compared to control. Statistical analysis showed a significant difference between both probiotics and chlorine in tomato. This research indicated that L.bulgaricus and S. salivarius could potentially be used as eco-friendly biocontrol agents in the produce industry.
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    Food borne bacteria isolated from spices and fate of Cronobacter sakazakii ATCC 29544 in black pepper exposed to drying and various temperature conditions
    (Academic Journals, 2013-03-19) Madela, Nokwanda; Ijabadeniyi, Oluwatosin Ademola
    The degree of infection of Juniperus procera roots by arbuscular mycorrhiza fungi (AMF) is highly indicative of the response of plants to environmental stress and is affected by the presence of flavonoids in the roots. However, relatively little is known about the relationship between soil textural components (sand, clay, silt content) and the percentage of AMF in the field soil. The aim of this work was to determine the relationship between soil textural components, content of flavonoids and AMF infection in the roots of J. procera. A significant correlation was found between AMF in the roots of J. procera and the soil textural components. A positive or negative correlation depended on each composition of soil texture. A negative correlation was found between the percent of AMF in the roots and the amount of coarse sand, fine sand and clay, while a positive correlation existed between the percent of AMF and silt. The degree of colonization with AMF was higher when the quantity of coarse sand was lower (r = -0.83). Similar trend was also observed with fine sand (r = -0.84), and clay (r = -0.83). On the contrary, root colonization with AMF was higher when the quantity of silt was higher (r = 0.92). This study demonstrated that the proportion of silt in the soil and the amount of flavonoid are strongly and positively correlated with AMF infection in the root of J. procera in Saudi Arabia.
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    Irrigation water and microbiological safety of fresh produce : South Africa as a case study : a review
    (Academic Journals, 2012-09-11) Ijabadeniyi, Oluwatosin Ademola; Buys, E. M.
    Irrigation water is perhaps the leading pre-harvest source of contamination of fresh produce in the world. In this review, the impact of contaminated surface irrigation water on bacterial contamination of fresh produce was examined. Some practical solutions to prevent or reduce this challenge were also considered. In South Africa, fruit and vegetables are produced on a large scale by commercial farmers who depend on surface water for their cultivation. However, the surface water, that is, rivers- has been reported to be heavily contaminated with Escherichia coli and feacal coliforms. There is a concern that contaminated surface water used for irrigation may contaminate fresh vegetables which may also have a negative effect on the export of vegetables to the EU and USA. Consumption of vegetables contaminated with foodborne pathogens presents a public health risk especially in countries like South Africa that has more than 5 million people with immune-system compromised diseases such as HIV and tuberculosis. Other groups of people that may be negatively affected because of the contaminated surface water are those who are directly and indirectly associated with the production of fresh vegetables such as pickers, handlers, packers and farmers that participate in the production of vegetables during pre-harvest and post-harvest. Prevention of contamination of fresh produce from both pre-harvest and post-harvest sources especially irrigation water still remains the only effective way to protect the public. However, for this to occur, every stakeholder in the production industry must have a culture of food safety.
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    Safety of nanofood : a review
    (Academic Journals, 2012-10-30) Ijabadeniyi, Oluwatosin Ademola
    Introduction of genetically modified (GM) foods generated a lot of controversy few years back, now it is the turn of nanofoods. There has been debate on the safety of foods that have been produced directly or indirectly with nanomaterials. Nanoparticles or nanotechnology procedures may be used to make food products, food additives, seeds and food packaging materials to give rise to a new and novel nanofood. While a lot have been written about the benefits of nanotechnology and nanomaterials in the food system, there is little research into the toxicological and possible hazard of nanofood. In this paper, the concept of nanotechnology, its diverse applications in the food industry and recent safety issues are considered. The paper concluded that it is necessary to do a thorough risk assessment of nanofoods before they are released to the market.