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Microbial Analyses (microbial + analysis)
Selected AbstractsMICROBIAL ANALYSIS AND TEXTURAL PROPERTIES OF CANTONESE SAUSAGEJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2010YANTAO WU ABSTRACT Cantonese sausage is one of the traditional meat products in China. In the present study, eight Cantonese sausage samples from different manufacturers were collected. Their microbial and textural properties were characterized. The chemical compositions were determined as follows: moisture, 15.18 ± 3.40%; protein, 33.75 ± 7.26% (expressed in dry matter); fat, 42.12 ± 6.64% (expressed in dry matter); total carbohydrates, 9.11 ± 3.73%; sodium chloride, 6.13 ± 0.41%; and sodium nitrite, 35.55 ± 6.69 mg/kg. The pH was determined to be 6.22 ± 0.14, while the acid value was 2.02 ± 0.71 mg potassium hydroxide/g lipid, and the peroxide value was 0.03 ± 0.04 g potassium iodide/100 g lipid. The total viable counts were 5.55 ± 1.48 log10 cfu/g, lactic acid bacteria were 3.59 ± 0.68 log10 cfu/g, staphylococci/micrococci were 3.96 ± 0.54 log10 cfu/g and yeasts/molds were 3.55 ± 0.47 log10 cfu/g. Staphylococci/micrococci were the dominant microbial group in Cantonese sausage. This was different from other sausages. The textural profiles of Cantonese sausage were determined as follows: average values of hardness, springiness, cohesiveness, gumminess and chewiness were 3,066.56 g, 0.96 mm, 0.57, 1,736.76 g and 1,658.26 g × mm, respectively. Analysis of between-variable relationships indicated that the pH value of Cantonese sausage was significantly correlated to its microbial and textural properties. PRACTICAL APPLICATIONS Cantonese sausage has gained much popularity and acceptance in China and many other countries. Commercial products from different manufacturers were collected in this work. The microbiological and textural characteristics of Cantonese sausage as well as the chemical compositions were evaluated. It is helpful to understand this type of sausage in order to improve its quality. [source] Sensory, Flavor, and Microbial Analyses of Raw, Pasteurized, and Irradiated Apple CidersJOURNAL OF FOOD SCIENCE, Issue 2 2005Fransiska Yulianti ABSTRACT: Ten trained descriptive panelists evaluated the sensory characteristics of raw, pasteurized, and irradiated apple cider, with and without sorbate. For the main effect of processing treatments, raw, pasteurized, and irradiated ciders were not different from each other in sweetness, sourness, astringency, and caramelized flavor. Irradiated cider had less apple flavor and lower ester content than raw cider. For the main effect of sorbate, the addition of sorbate (0.05%) increased sweetness. Irradiated cider had higher musty flavor than both raw and pasteurized ciders, and the addition of sorbate to irradiated cider further increased musty flavor. The addition of potassium sorbate to apple cider effectively reduced yeast and aerobic bacteria counts and minimized the degradation of several esters during irradiation. [source] Effect of loading rate on TOC consumption efficiency in a sulfate reducing process: sulfide effect in batch cultureJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 12 2008Citlali García-Saucedo Abstract BACKGROUND: The sulfate reducing process (SRP) was analyzed in order to identify factors that diminish the effectiveness of the SRP during wastewater treatment. The effect of different sulfate loading rates (SLR, 290 to 981 mg SO4 -S L,1d,1) and lactate at a stoichiometric C/S ratio of 0.75 on SRP was studied in an upflow anaerobic sludge blanket (UASB) reactor. The effect of sulfide concentration (0 to 200 mg sulfide-S L,1) on SRP in batch culture was evaluated. RESULTS: When the SLR was increased, the total organic carbon (TOC) and sulfate consumption efficiencies decreased from 93% ± 3 to 66% ± 2 and 60% ± 5 to 45% ± 4, respectively. Acetate and propionate were accumulated. Microbial analysis showed the presence of microorganisms related with the SRP, fermentation and methanogenesis. In batch culture, when lactate and sulfate were present, SRP and fermentation were observed. When sulfide was added only SRP was observed. At concentrations higher than 150 mg sulfide-S L,1 the efficiencies, yields and specific consumption rates (q) decreased. CONCLUSION: Based on the sulfide-S/volatile suspended solid ratio, it was found that the decrease in efficiency and accumulation of acetate and propionate in the UASB reactor was not related to sulfide inhibition but to the q of acetate and propionate, which were up to 11 times lower than lactate. Copyright © 2008 Society of Chemical Industry [source] Tracing Salmonella in Alheira processing plantsJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2007A. Esteves Abstract Aims:, To investigate the sources of Salmonella spp. in Alheira and how to trace it, by studying the way that Salmonella spp. is distributed across production lines, by applying multifactorial correspondence analysis to occurrence data, and through the use of polymerase chain reaction (PCR) molecular typing methods. Methods and Results:, Four production lines, four batches of Alheira and 14 sampling sites were analysed over four sampling periods. Eighty-five Salmonella spp. isolates were obtained from the 896 microbial analyses performed. The basic occurrence analysis values, multiple correspondence analysis and PCR molecular typing methods confirmed that the presence of Salmonella spp. in Alheira was directly related to it being present in casings. Results obtained from PCR molecular typing added a measure of detail, highlighting potential cross-path contamination caused by contaminated surfaces. Conclusions:, The presence of Salmonella spp. in Alheira was a result of the use of contaminated casings, as well as cross-path contamination caused by contaminated surfaces. An analysis of the occurrence data indicated that these casings were the source of Salmonella spp. contamination in Alheira. PCR molecular typing methodology, which is known to have a greater discriminatory power and tracing capacity, indicated the presence of cross-path contamination. Significance and Impact of this Study:, Increased awareness of Salmonella spp. contamination sources and their spread across the production line helps shape the development of new strategies for controlling this pathogen. [source] Recovery of,Salmonella enterica,Serovars Typhimurium and Tennessee in Peanut Butter after Electron Beam ExposureJOURNAL OF FOOD SCIENCE, Issue 7 2010Kristen E. Matak Abstract:, The effect of electron beam (e-beam) radiation on the recovery of,Salmonella,serotypes Tennessee (ATCC 10722) and Typhimurium (ATCC 14028) in creamy peanut butter over a 14-d storage period at 22 °C was studied. Each,Salmonella,type was independently inoculated into peanut butter and subjected to e-beam doses that ranged from 0 to 3.1 kGy, confirmed by film dosimetry. After 2-, 4-, 6-, 8-, and 14-d of storage, microbial analyses were conducted. Survivors were recovered on growth and selective media using standard spread-plating methods. Microbial counts (CFU/g) were log-converted and differences were determined by ANOVA and Tukey's Honestly Significant Differences test. When samples were not e-beam-treated, there were no significant changes (P,> 0.05) in microbial numbers over time. In e-beamed samples, microbial numbers decreased over time; however, reductions were not always significant. Initial recovery rates (R-rates) 2 d after e-beam treatment were significantly different for the 2 strains of,Salmonella,and between recovery media (P,< 0.05); however, these differences did not persist for the remainder of the storage period (P,> 0.05) indicating that injured cells were not able to survive in the high-fat, low-water activity peanut butter environment. R-rates for both strains of,Salmonella,were maintained until day 14 when there were significant reductions in,Salmonella,Typhimurium (P,< 0.05). These results indicate that,Salmonella,Tennessee and,Salmonella,Typhimurium will survive in peanut butter when exposed to nonlethal doses of e-beam irradiation. Practical Application: Electron beam (e-beam) irradiation is an alternative to thermal processing; this technique inactivates microorganisms and insects that might be present in a food by generating radiation by accelerated electrons that inactivate organisms directly because of interaction with cell components and indirectly by producing free radicals that disrupt integrity of the cell membrane. E-beam radiation will reduce the number of probable microbiological hazards that could be present while the food remains generally unaffected in texture, taste, and nutritional value. A recent study showed e-beam irradiation to be effective at reducing both,Salmonella,Tennessee and Typhimurium in peanut butter by one log after exposure to less than 1 kGy, highlighting the need to explore this process further. [source] Laboratory preparation and evaluation of Pollock variety avocado (Persea americana Mill) guacamoleJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2007Giselle A Ramtahal Abstract Guacamole was produced from ripe avocado (Persea americana) by blending the pulp with local herbs, spices and salt. The guacamole was stored at 5 °C for 2 weeks, during which physical, chemical and microbial analyses were conducted. Organoleptic evaluations by a semi-trained panel were also performed, until the guacamole was deemed unfit for human consumption. The results indicated that fresh avocado pulp contains 835, 13, 16, 92, 44, 16 and 0.078 g kg,1, moisture, ash, protein, fat, carbohydrate, fiber, and vitamin C respectively, and has a pH of 6.7; compared with 838, 13, 16, 92, 44, 16, and 0.042 g kg,1, respectively, of the same nutrients in freshly prepared guacamole, which has a pH of 6.0. During storage, the moisture content, consistency, total soluble solids and total titratable acidity (as citric acid) of the guacamole increased, but the vitamin C content decreased. The color of the avocado pulp, which darkened during conversion into guacamole, darkened further as storage increased as evidenced by a decrease in the L, a and b values. Sensory evaluation revealed that the mean storage period (5 °C) for the guacamole was 6 days. Although the fresh avocado pulp, the freshly prepared guacamole, and the stored guacamole contained bacteria, yeasts and molds, the pathogens Staphylococcus aureus and Salmonella were absent. Copyright © 2007 Society of Chemical Industry [source] The ripening and aging of noni fruits (Morinda citrifolia L.): microbiological flora and antioxidant compoundsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2007Yanine Chan-Blanco Abstract The juice of noni fruit (Morinda citrifolia L.) is claimed to be a natural functional beverage with a growing market both in the USA and Europe. It is traditionally produced by keeping harvested fruit in closed containers for several weeks as the fruit senesces or ages. Little is known about the changes that occur in the juice's microbiological, physicochemical, and functional characteristics during this treatment. Traditional processing was simulated in the laboratory, with samples being recovered and analyzed at various time intervals. At first, fermentation occurred and populations of molds, yeasts, and mesophilic bacteria increased significantly. After 2 weeks, microbial growth changed abruptly, stopping for yeasts, molds, and mesophilic bacteria, and decreasing suddenly for lactic bacteria. Analyses of pH, soluble solids, ethanol, and lactic acid in the fruits confirmed the microbial analyses, indicating initial sensitive variations, followed by values remaining comparatively steady during aging. Vitamin C and total phenol contents also remained constant at 300 ± 60 mg and 50 ± 20 mg GAE, respectively, per 100 g of pulp. Antioxidant capacity likewise remained relatively high at 8 ± 1.5 µmol Trolox® g,1. All phenolic compounds, including scopoletin and rutin, varied significantly immediately after harvest but remained more or less steady during aging. Copyright © 2007 Society of Chemical Industry [source] Use of rpoB and 16S rRNA genes to analyse bacterial diversity of a tropical soil using PCR and DGGELETTERS IN APPLIED MICROBIOLOGY, Issue 4 2002R.S. Peixoto Aim: To evaluate the rpoB gene as a biomarker for PCR-DGGE microbial analyses using soil DNA from the Cerrado, Brazil. Methods: DNA extraction from soil was followed by Polymerase Chain Reaction (PCR) amplification of rpoB and 16S rRNA genes. PCR products were compared by Denaturing Gradient Gel Electrophoresis (DGGE) to compare gene/community profiles. Results: The rpoB DGGE profiles comprised fewer bands than the 16S rDNA profiles and were easier to delineate and therefore to analyse. Comparison of the community profiles revealed that the methods were complementary. Conclusions, Significance and Impact of the Study: The gene for the beta subunit of the RNA polymerase, rpoB, is a single copy gene unlike 16S rDNA. Multiple copies of 16S rRNA genes in bacterial genomes complicate diversity assessments made from DGGE profiles. Using the rpoB gene offers a better alternative to the commonly used 16S rRNA gene for microbial community analyses based on DGGE. [source] Mortadella Sausage Formulations with Partial and Total Replacement of Beef and Pork Backfat with Mechanically Separated Meat from Spent Layer HensJOURNAL OF FOOD SCIENCE, Issue 3 2005Marco A. Trindade ABSTRACT: Mortadella sausages were formulated with 0%, 20%, 40%, 60%, 80%, and 100% mechanically separated layer hen meat (MSLM) replacing the beef and pork backfat as raw materials. Treatments were compared by determination of shear force, sensory acceptance, and stability during cold storage (microbial analysis, thiobarbituric acid-reactive substances [TBARS], color, and descriptive sensory analysis). Mortadella with higher MSLM presented lower shear force values. TBARS index and sensory rancidity were not affected. The greater the amounts of MSLM used, the paler was the pink color observed in the sensory evaluations and the lower were the CIE a* values. All treatments presented minimal increase in the microbiological counts evaluated during storage. The limiting factor in the acceptance of the product was the perception of bone particles in mortadella containing 60% or more MSLM. [source] | |||||||||||||