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Bacterial Reduction (bacterial + reduction)
Selected AbstractsThe effect of ultrasonically activated irrigation on reduction of Enterococcus faecalis in experimentally infected root canalsINTERNATIONAL ENDODONTIC JOURNAL, Issue 11 2010A. J. Harrison Harrison AJ, Chivatxaranukul P, Parashos P, Messer HH. The effect of ultrasonically activated irrigation on reduction of Enterococcus faecalis in experimentally infected root canals. International Endodontic Journal, 43, 968,977, 2010. Abstract Aim, To investigate the ability of an ultrasonically activated irrigating system to eliminate bacteria from the canal wall and dentinal tubules of extracted teeth. Methodology, One hundred and thirty roots of intact human teeth were inoculated with Enterococcus faecalis for 4 weeks. The straight roots were randomly allocated to a baseline group (n = 25) or subjected to routine cleaning and shaping procedures (n = 105). Two sub-groups of prepared canals were then additionally exposed either to ultrasonic irrigation with 1% sodium hypochlorite (NaOCl) for 1 min (n = 35) or to 1 week of intracanal medication with calcium hydroxide [Ca(OH)2] (n = 35). All roots were processed for light microscopy (Brown and Brenn stain) (n = 28) or scanning electron microscopy (n = 7). Triplicate histological sections from each of the apical, middle and coronal thirds were scored for bacterial presence using pre-defined criteria. Results, Baseline bacterial penetration resulted in an average depth of tubule invasion of 151 ,m. Routine canal preparation failed to eliminate bacteria consistently from either the canal wall or within tubules. Ultrasonic irrigation and medication with Ca(OH)2 consistently eliminated bacteria from the canal wall (P < 0.001) compared with baseline and routine treatment, and more frequently from dentinal tubules than routine canal preparation alone (P < 0.01). Ultrasonic irrigation was as effective in bacterial reduction as 1 week of intracanal medication with Ca(OH)2, but neither led to complete bacterial elimination in all roots. Conclusions, Ultrasonically activated irrigation for 1 min with 1% NaOCl after canal preparation in straight root canals is potentially an effective supplementary step in microbial control. [source] EFFECT OF MARINADE AND DRYING TEMPERATURE ON INACTIVATION OF ESCHERICHIA COLI O157:H7 ON INOCULATED HOME DRIED BEEF JERKYJOURNAL OF FOOD SAFETY, Issue 3 2002SUSAN N. ALBRIGHT ABSTRACT Beef slices were inoculated (5.7,7.5 log CFU/cm2) with a 4-strain composite of E. coli O157:H7, stored (4C, 24 h), marinated (4C, 24 h), dried for 10 h at 62.5C or 68.3C, and stored for 90 days at 21C. Unmarinated beef slices dried for 10 h at 62.5C were used to determine the relative contribution of the marinate versus temperature treatment in the 62.5C trials. Samples were analyzed (bacterial enumeration with selective and nonselective agar media, pH, and aw) following inoculation, marinating, at 4, 6, 8 and 10 h of drying, and after 30, 60 and 90 days of storage. Marination resulted in slight changes in bacterial populations (,0.3 to + 0.6 log CFU/cm2), but did not enhance bacterial reduction during drying. For all treatments, most bacterial reductions occurred in the first 4 h of drying, with little reduction thereafter. After 10 h of drying, bacterial reductions were 3.2,3.4 log CFU/cm2 for unmarinated beef slices dried at 62.5C. Reductions of 2.2 and 3.0,4.6 log CFU/cm2 were achieved in marinated jerky slices dried at 62.5C and 68.3C, respectively. No treatment resulted in the recommended 5-log reduction at the end of 10 h drying. However, bacteria did become undetectable by direct plating (<10 CFU/cm2) following 30 days of storage in all treatments except the unmarinated beef slices plated on tryptic soy agar (TSA). Additional work is needed to develop procedures for adequate destruction of E. coli O157:H7 during drying of beef jerky. [source] Stereospecific reduction of the original anticancer drug oracin in rat extrahepatic tissuesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 7 2003Barbora Szotáková ABSTRACT The liver is the major site of drug metabolism in the body. However, many drugs undergo metabolism in extrahepatic sites and in the gut wall and lumen. In this study, the distribution and activity of reductases in rat that reduced potential cytostatic oracin to its principal metabolite 11-dihydrooracin (DHO) were investigated. The extension and stereospecificity of oracin reduction to DHO were tested in microsomal and cytosolic fractions from the liver, kidney, heart, lung and wall of small intestine, caecum and large intestine. Intestinal bacterial reduction of oracin was studied as well. The amount of DHO enantiomers was measured by HPLC with Chiralcel OD-R as chiral column. Reductive biotransformation of oracin was mostly stereospecific for (+)-DHO, but the enantiomeric ratio differed significantly among individual tissues and subcellular fractions (from 56% (+)-DHO in heart microsomes to 92% (+)-DHO in liver cytosol). Stereospecificity for (-)-DHO (60%) was observed in bacterial oracin reduction in the lumen of small intestine, caecum and large intestine. Shift of the (+)-DHO/(-)-DHO enantiomeric ratio from 90:10 (in liver subcellular fractions) to 60:40 (in-vivo) clearly demonstrated the importance of the contribution of extrahepatic metabolism to the total biotransformation of oracin to DHO. [source] EFFECT OF MARINADE AND DRYING TEMPERATURE ON INACTIVATION OF ESCHERICHIA COLI O157:H7 ON INOCULATED HOME DRIED BEEF JERKYJOURNAL OF FOOD SAFETY, Issue 3 2002SUSAN N. ALBRIGHT ABSTRACT Beef slices were inoculated (5.7,7.5 log CFU/cm2) with a 4-strain composite of E. coli O157:H7, stored (4C, 24 h), marinated (4C, 24 h), dried for 10 h at 62.5C or 68.3C, and stored for 90 days at 21C. Unmarinated beef slices dried for 10 h at 62.5C were used to determine the relative contribution of the marinate versus temperature treatment in the 62.5C trials. Samples were analyzed (bacterial enumeration with selective and nonselective agar media, pH, and aw) following inoculation, marinating, at 4, 6, 8 and 10 h of drying, and after 30, 60 and 90 days of storage. Marination resulted in slight changes in bacterial populations (,0.3 to + 0.6 log CFU/cm2), but did not enhance bacterial reduction during drying. For all treatments, most bacterial reductions occurred in the first 4 h of drying, with little reduction thereafter. After 10 h of drying, bacterial reductions were 3.2,3.4 log CFU/cm2 for unmarinated beef slices dried at 62.5C. Reductions of 2.2 and 3.0,4.6 log CFU/cm2 were achieved in marinated jerky slices dried at 62.5C and 68.3C, respectively. No treatment resulted in the recommended 5-log reduction at the end of 10 h drying. However, bacteria did become undetectable by direct plating (<10 CFU/cm2) following 30 days of storage in all treatments except the unmarinated beef slices plated on tryptic soy agar (TSA). Additional work is needed to develop procedures for adequate destruction of E. coli O157:H7 during drying of beef jerky. [source] Numerical Analysis of Survival of Listeria monocytogenes during In-Package Pasteurization of Frankfurters by Hot Water ImmersionJOURNAL OF FOOD SCIENCE, Issue 5 2007Lihan Huang ABSTRACT:, The objective of this research was to develop and validate a more accurate method to analyze and calculate the inactivation of Listeria monocytogenes in frankfurter packages during postlethality hot water immersion heating and the subsequent cooling processes. Finite difference analysis with implicit scheme was used to simulate the heat transfer process during in-package pasteurization of frankfurters. A volumetrically distributed simulation method was developed to calculate the lethality of the thermal treatment. The simulation method was validated using frankfurter packages inoculated with a 4-strain cocktail of L. monocytogenes. Experimental results showed that the numerical analysis model could accurately simulate the heat transfer process during heating and cooling of frankfurter packages. The simulated temperatures on the surface or in the middle of the package matched very closely with the experimental observations. Using the simulated temperature distribution in the packages, the integrated lethality simulation method, based on the volumetric distribution of bacteria, could accurately predict the reduction in the bacterial counts. The calculation results were on average within 0.3 log(CFU/g) difference from the experimental observations, while the General Method systematically underestimated the bacterial reductions by approximately 0.9 log(CFU/g). The study shows that the integrated lethality method is more accurate than the General Method in calculating the lethality of thermal processes for conduction-heated foods. [source] | |||||||||||||