Changes In Microbial Profiles Research Articles

Reliable screening of various foodstuffs with respect to their irradiation status: A comparative study of different analytical techniques

Cost-effective and time-efficient analytical techniques are required to screen large food lots in accordance to their irradiation status. Gamma-irradiated (0–10kGy) cinnamon, red pepper, black pepper, and fresh paprika were investigated using photostimulated luminescence (PSL), direct epifluorescent filter technique/the aerobic plate count (DEFT/APC), and electronic-nose (e-nose) analyses. The screening results were also confirmed with thermoluminescence analysis. PSL analysis discriminated between irradiated (positive, >5000PCs) and non-irradiated (negative, <700PCs) cinnamon and red peppers. Black pepper had intermediate results (700–5000PCs), while paprika had low sensitivity (negative results) upon irradiation. The DEFT/APC technique also showed clear screening results through the changes in microbial profiles, where the best results were found in paprika, followed by red pepper and cinnamon. E-nose analysis showed a dose-dependent discrimination in volatile profiles upon irradiation through principal component analysis. These methods can be used considering their potential applications for the screening analysis of irradiated foods.

Quality of fried broiler chicken leg muscles stored at different temperatures

Chicken leg pieces (60 g each). with optimized quantity of additives were fried in hydrogenated vegetable oil at 180°C for 8 min. The fried product was packed in paper-foil-polyethylene pouches (PFP) and stored under ambient (20 ± 5°C, 65-80% RH), refrigerator (5°C, 80% RH) and deep freezer (-18°C, 85-90% RH) conditions. The changes in microbial profile, oxidative and hydrolytic rancidity and sensory quality were evaluated periodically. It was found that the product was microbiologically (standard plate count (SPC) < 3 log cfu/g) safe and sensorily acceptable (overall acceptability >7) up to 4 days under ambient conditions. Hydrolytic and oxidative rancidity values during four days storage at room temperature were less than 0.16 % oleic acid and 3.5 mg malonaldehyde/kg, respectively. The products stored under refrigerated and deep freezer exhibited a shelf stability of 10 and 18 weeks, respectively. SPC was 1.3 log cfu/g while rancidity parameters were free fatty acid < 0.43% oleic acid and thiobarbituric acid reactive substances were <6.13 mg malonaldehyde/kg. Sensorily the product exhibited an overall acceptability score of >7 on a 9-point Hedonic scale during refrigerated and frozen storage.

Comparative Analysis of Fecal Microbiota in Infants with and without Eczema

Eczema is a chronic form of childhood disorder that is gaining in prevalence in affluent societies. Previous studies hypothesized that the development of eczema is correlated with changes in microbial profile and composition of early life endemic microbiota, but contradictory conclusions were obtained, possibly due to the lack of minimization of apparent non-health related confounders (e.g., age, antibiotic consumption, diet and mode of delivery). In this study, we recruited seven caesarean-delivered and total formula-fed infants, and comparatively examined the early-life endemic microbiota in these infants with and without eczema. Using 16S pyrosequencing, infants' fecal microbiota were observed to comprise Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes as the four main phyla, and the presence and absence of specific populations within these four phyla are primarily mediated by ageing. Quantitative analysis of bacterial targets on a larger sample size (n = 36 at 1, 3, and 12 months of age) revealed that the abundances of Bifidobacterium and Enterobacteriaceae were different among caesarean-delivered infants with and without eczema, and the bacterial targets may be potential biomarkers that can correlate to the health status of these infants. Our overall findings suggest that the minimization of possible confounders is essential prior to comparative evaluation and correlation of fecal microbiota to health status, and that stool samples collected from caesarean-delivered infants at less than 1 year of age may represent a good cohort to study for potential biomarkers that can distinguish infants with eczema from those without. These findings would greatly facilitate future efforts in understanding the possible pathogenesis behind certain bacterial targets, and may lead to a timely intervention that reduces the occurrence of early life eczema and possibly allergic disorders in later life.

Microbiological and acidity changes during the traditional production of kirario: An indigenous Kenyan fermented porridge produced from green maize and millet.

Using a previously pre-tested structured questionnaire, the traditional processing method for kirario (a traditional fermented porridge of the Merus in Kenya) was studied and documented. The biochemical and microbial profile changes during fermentation of kirario, both by the traditional method and in the laboratory were monitored for 48 hours. Samples of kirario from ten localities in the study region were analyzed. Samples of the final products from the traditional method were analyzed for total viable counts (TVC), lactic acid bacteria (LAB), lactococci, yeastsand moulds and coliforms, while the laboratory samples were taken at six (6)-hour intervals and analyzed for TVC, LAB, lactococci, and yeasts and moulds for 48 hours. The traditional product showed average TVC, LAB, lactococci, yeasts and moulds of 9.30, 9.63, 8.62, and 4.83 log10 cfu/ml, respectively. Coliform counts were detected in only two of the samples at

Probiotics and Irritable Bowel Syndrome

Growing evidence suggests a potential role of intestinal microbiota in irritable bowel syndrome (IBS) pathophysiology and symptom generation. Earlier studies based on classic microbiologic techniques hypothesized the presence of qualitative changes in intestinal microbiota in IBS patients. Recently, studies with molecular techniques have provided evidence of significant changes in microbial profiles in IBS and that the composition may be correlated with certain symptoms reported by patients. Although these studies are far from being exhaustive and conclusive they provide promising results that deserve further investigation. In addition, initial evidence indicated the presence of increased amounts of bacteria in the upper small intestine of IBS patients, a condition know as small intestinal bacterial overgrowth. However, the results of these studies have provided contradictory results suggesting that this area requires further work. These qualitative and quantitative changes in intestinal microbiota may induce different effects on the intestinal mucosa including mucosal barrier defects and immune activation which may contribute to symptom generation. Studies in IBS patients have attempted to target changes in intestinal microflora with different therapeutic approaches, such as the use of prebiotics, probiotics, synbiotics, and nonabsorbable and systemic antibiotics. Overall, the results obtained in probiotic clinical trials suggest some beneficial effect over placebo in the relief of IBS symptoms. However, these results, although encouraging, should be confirmed in larger well-designed, placebo-controlled studies. A number of open questions remain to be addressed, including the dose, type, and time of administration of probiotics.

Microbial community responses associated with the development of oomycete plant pathogens on tomato roots in soilless growing systems

To determine the spread of different oomycete pathogens in hydroponic, soilless tomato growing systems and their impact on established microbial communities, as baseline studies prior to future introduction of microbial inoculants for disease suppression. The oomycete pathogens, Pythium group F, Pythium aphanidermatum and Phytophthora cryptogea, were introduced into small-scale recirculating tomato growing systems containing rockwool 6 weeks after set-up when roots were well-established. Two weeks later, half of the systems were switched over to run-to-waste. Pythium aphanidermatum spreads the fastest, Pythium group F the slowest and Ph. cryptogea was intermediate in its spread. The switch to run-to-waste had no effect on pathogen recovery. Microbial communities, monitored by dilution plating, were well-established at the first sampling, 6 weeks after set-up and although differences in community levels were found between experiments, changes during any one experiment were small, generally less than 1 log10 CFU g(-1) for bacteria. Pathogen introduction increased microbial community levels in roots but the switch to run-to-waste had no effect. Analysis of bacterial communities through amplification of a fragment of the 16S rRNA gene and DGGE profiling showed that different communities were established within each pathogen experiment and that different communities were established on roots, rockwool and in nutrient solutions. However, no significant changes in microbial profiles were found over time in any experiment. In these systems, the microbial communities were well-established 6 weeks after set-up and were resistant to biological and physical perturbation. The implication for microbial inoculation of such systems for disease suppression is that the micro-organisms would either have to be introduced very early during the set-up of the system or be able to replace an established but variable community.