Author
Jonathan Rhoades
Other affiliations: University of Reading, London South Bank University, Aristotle University of Thessaloniki ...read more
Bio: Jonathan Rhoades is an academic researcher from American Hotel & Lodging Educational Institute. The author has contributed to research in topics: Antimicrobial & Escherichia coli. The author has an hindex of 16, co-authored 19 publications receiving 2258 citations. Previous affiliations of Jonathan Rhoades include University of Reading & London South Bank University.
Papers
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TL;DR: Electron microscopy showed that chitosan caused extensive cell surface alterations and covered the OM with vesicular structures, explaining the loss of the barrier function of the outer membrane, which makes chitOSan a potentially useful indirect antimicrobial for food protection.
1,173 citations
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TL;DR: It is concluded that native chitosan has potential for use as a preservative in certain types of food but that the increase in antimicrobial activity that occurs following partial hydrolysis is too small to justify the extra processing involved.
Abstract: The objective of this study was to determine whether chitosan (poly-β-1,4-glucosamine) and hydrolysates of chitosan can be used as novel preservatives in foods. Chitosan was hydrolyzed by using oxidative-reductive degradation, crude papaya latex, and lysozyme. Mild hydrolysis of chitosan resulted in improved microbial inactivation in saline and greater inhibition of growth of several spoilage yeasts in laboratory media, but highly degraded products of chitosan exhibited no antimicrobial activity. In pasteurized apple-elderflower juice stored at 7°C, addition of 0.3 g of chitosan per liter eliminated yeasts entirely for the duration of the experiment (13 days), while the total counts and the lactic acid bacterial counts increased at a slower rate than they increased in the control. Addition of 0.3 or 1.0 g of chitosan per kg had no effect on the microbial flora of houmous, a chickpea dip; in the presence of 5.0 g of chitosan per kg, bacterial growth but not yeast growth was substantially reduced compared with growth in control dip stored at 7°C for 6 days. Improved antimicrobial potency of chitosan hydrolysates like that observed in the saline and laboratory medium experiments was not observed in juice and dip experiments. We concluded that native chitosan has potential for use as a preservative in certain types of food but that the increase in antimicrobial activity that occurs following partial hydrolysis is too small to justify the extra processing involved.
407 citations
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TL;DR: Seasonal variation was evident in many surveys, faecal prevalences of E. coli O157 and Salmonella generally being higher in the warmer months, and the significance of non-O157 serotypes of VTEC and their detection and classification are discussed.
234 citations
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TL;DR: Cheeses were of unsatisfactory quality more frequently when sampled from premises rated as having little or no confidence in management and control systems, and stored/displayed at above 8 degrees C.
172 citations
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TL;DR: The ability of chito-oligosaccharides (COS) to inhibit selected intestinal bacteria was investigated and dose–response curves were constructed to further characterise the inhibition of EPEC strains to HT29 cells.
68 citations
Cited by
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TL;DR: The current review of 129 references describes the biological activity of several chitosan derivatives and the modes of action that have been postulated in the literature.
2,615 citations
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TL;DR: The chemical structure and relevant biological properties of chitosan for regenerative medicine have been summarized as well as the methods for the preparation of controlled drug release devices and their applications.
2,312 citations
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TL;DR: The paper reviews the current trend of investigation on antimicrobial activities of chitosan and its mode of action and different physical states are comparatively discussed.
2,260 citations
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TL;DR: Several selected pharmaceutical and biomedical applications are presented, in which chitin and chitosan are recognized as new biomaterials taking advantage of their biocompatibility and biodegradability.
Abstract: This review describes the most common methods for recovery of chitin from marine organisms. In depth, both enzymatic and chemical treatments for the step of deproteinization are compared, as well as different conditions for demineralization. The conditions of chitosan preparation are also discussed, since they significantly impact the synthesis of chitosan with varying degree of acetylation (DA) and molecular weight (MW). In addition, the main characterization techniques applied for chitin and chitosan are recalled, pointing out the role of their solubility in relation with the chemical structure (mainly the acetyl group distribution along the backbone). Biological activities are also presented, such as: antibacterial, antifungal, antitumor and antioxidant. Interestingly, the relationship between chemical structure and biological activity is demonstrated for chitosan molecules with different DA and MW and homogeneous distribution of acetyl groups for the first time. In the end, several selected pharmaceutical and biomedical applications are presented, in which chitin and chitosan are recognized as new biomaterials taking advantage of their biocompatibility and biodegradability.
1,554 citations
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TL;DR: The most promising nanoscale fillers are layered silicate nanoclays such as montmorillonite and kaolinite as mentioned in this paper, which can provide active and/or smart properties to food packaging systems.
1,461 citations