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|a eng
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|9 17241
|a Al Rashed, Nasser Saad
|e Author
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|a Activation of Bacillus Spores by Heat, Alanine, and Peptidoglycan Treatments
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|a بريزبن
|c 2010
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|a 1 - 59
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|a رسائل جامعية
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|b رسالة ماجستير
|c Queensland University
|f School of Land, Crop and Food Sciences
|g أستراليا
|o 0001
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|a Bacillus species form spores that are metabolically dormant and survive harsh environmental conditions. Spores continually monitor their environment and germinate under favourable conditions. Spores of a number of Bacillus species are generally present in milk and are implicated in food spoilage and food-borne disease. Bacillus spores comprise of dormant and superdormant spores. While dormant spores can germinate faster and then easy to kill by wet heat treatment, the superdormant spores require high temperatures, techniques that are costly and detrimental to food quality. An alternative method is to induce germination of these spores before killing them. A good knowledge of germination process and its associate kinetics is needed to advocate the critical method for inducing maximum spore germination. Various methods of activation of spores have been reported by earlier workers which include heat activation, activation by nutrients and activation by peptidoglycan, time interval etc. The present study was conducted to compare the efficacy of three methods of spore activation, namely, heat activation, activation with L-alanine and peptidoglycan on two species of Bacillus; Bacillus subtilis and Bacillus cereus. Spores were treated by three ways to induce germination each treatment was divided into two groups, one for test and one for control. Each group had two tubes containing spores which were either heat treated at 800 C or were not treated. The results were evident that spores of B. cereus showed significantly consistent activation following heat treatment and activation with peptidoglycan while germination rates were depressed in presence of L-alanine. The spores B. subtilis did not show activation with any of the three process. The results of activation of germination rates in B.cereus could not be consistently reproduced which could be due to the presence of germinant inhibitors or due to delayed germination as evidenced by earlier workers. The present findings indicate that the dynamics of spore activation is a complex process which differs within strains of a species and needs better understanding. Further research needs to concentrate on the role of receptors and composition of the germinant mixture to determine the critical parameters required for maximal activation of spore germination while preserving the qualities of milk or milk products.
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|a الجراثيم
|a الايض
|a الاغذية
|a الامراض
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| 700 |
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|9 50461
|a Turner, Mark
|e Advisor
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|u 9843-008-005-0001-T.pdf
|y صفحة العنوان
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|u 9843-008-005-0001-A.pdf
|y المستخلص
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|u 9843-008-005-0001-C.pdf
|y قائمة المحتويات
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|u 9843-008-005-0001-F.pdf
|y 24 صفحة الأولى
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|u 9843-008-005-0001-1.pdf
|y 1 الفصل
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|u 9843-008-005-0001-2.pdf
|y 2 الفصل
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|u 9843-008-005-0001-3.pdf
|y 3 الفصل
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|u 9843-008-005-0001-4.pdf
|y 4 الفصل
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|u 9843-008-005-0001-O.pdf
|y الخاتمة
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|u 9843-008-005-0001-R.pdf
|y المصادر والمراجع
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|u 9843-008-005-0001-S.pdf
|y الملاحق
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|d n
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|a +Dissertations
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|c 615717
|d 615717
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