Total Bacterial Research Articles

Chemical Composition, Microbiological and Sensory Qualities of Banana Based Complementary Diets Fortified with African Breadfruit Seed and Carrot Flours

About the age of six months, an infant requires more nutrients and energy than those provided by the breast milk, and complementary diets are therefore introduced to meet those needs. The objective of this study was therefore to develop and evaluate complementary diets from cooking banana, African breadfruit seeds and carrot flour blends. Ratios of cooking banana, African breadfruit seed and carrot flour blends in 90:0:10 as Diet 1, 85:5:10 as Diet 2, 80:10:10 as Diet 3, 75:15:10 as Diet 4 and 70:20:10 as Diet 5, were used for formulation of complementary diets. The flour blends for diet production showed bulk density and gelatinization temperature decreased from 0.98 to 0.65 g/ml and 85.67 to 78.10oC respectively, while swelling and water absorption capacity increased from 268.33 to 295.00% and 208.33 to 243.33% respectively, with increase in African breadfruit seed flour in the composite blends. Phytate (1.25 – 11.03 mg/100g) and trypsin inhibitor activities (1.05 – 1.17 TIU/100g) increased with increasing African breadfruit flour supplementations. Proximate composition of diets showed increased protein (2.16 – 18.47%), fat (1.81 – 2.23%), ash (2.42 – 2.96 %) and decreased carbohydrate (73.14 – 89.80%). Iron and calcium content of Diets increased from 14.11 – 19.23mg/100g and 28.24 – 43.23 mg/100g, while magnesium decreased from 6.24 – 8.25mg/100g respectively with increasing African breadfruit flour. Vitamin A and C decreased from 13.09 to 9.16 and 0.98 – 0.75mg/100g respectively. Microbial quality of all Diets developed were within the acceptable limit of 103 cfu/g for both total bacterial (TBC) and total fungal count (TFC). Diet 3 (80:10:10) was most accepted in sensory qualities. Complementary diets produced with 80% cooking banana, 10% African breadfruit seed and 10% carrot flour blends could help fill the gaps, when transitioning from breast milk to family diet, to provide the essential nutrients and energy required for infant’s activity, optimum growth and development.

Distribution and the trend of airborne particles and bio-aerosol concentration in pediatric intensive care units with different ventilation setting at two hospitals in Riyadh, Saudi Arabia

ObjectiveTo examine the distribution and the trend of airborne particles and bio-aerosol concentration in pediatric intensive care units (PICUs) in two tertiary care hospitals with different ventilation setting. MethodsHospitals A but not B is provided with a central HEPA filter. PICUs in both hospitals were categorized into protective environment (PE) with room HEPA filter, semi-protective environment (SPE) with portable air-purifier, and non-protective environment (NPE) with neither system. Fine particles (≤ 2.5 µm) and coarse particles (≤ 10.0 µm) were obtained using optical particle counter (Lighthouse Handheld 3016) and total bacterial (TBC) and fungal (TFC) counts were obtained using Andersen air sampler. ResultsHospital B had significantly higher levels of fine and coarse particles (in all room), TBC (in PE), but not TFC compared with matched rooms in hospital A. In hospital B, the levels of fine particles, coarse particles, and TBC were lowest in SPE (p < 0.001, p = 0.004, and p = 0.006, respectively) while TFC was lowest in NPE (p = 0.014). Airborne particles, TBC, and TFC had variable trends with some of the indoor peaks follow outdoor peaks. Gram-positive bacteria (69 %) were the predominant bacteria in hospital A while bacterial flora (70 %) were the predominant bacteria in hospital B (p < 0.001 for each). ConclusionsThe levels of airborne contaminants and microbial counts in PICUs are significantly affected by the ventilation system and to less extent by outdoor levels. The results indicated that advanced filtration system and central HEPA filters play a significant role in the reduction of indoor fine particulates and TBC.

Spatiotemporal patterns and environmental drivers of total and active bacterial abundances in Lake Taihu, China

• 120 samples were seasonally sampled to identify bacterial patterns in Lake Taihu. • Total and active bacterial abundances (TB-AB) varied dramatically among seasons. • On average, active bacteria accounted for ~10% of the total bacterial abundance. • Nitrogen, phosphorus, organic carbon and temperature mostly shaped AB variation. • AB is a more sensitive bioindicator of environmental changes than total bacteria. Bacteria are a key component in lake ecosystems, playing a crucial role in driving biogeochemical and energy fluxes. In lake biomonitoring, false alarms have often been triggered due to the presence of abundant dead or dormant bacterial cells. Thus, quantification of the metabolically active and dormant cells is required for effective biomonitoring. In this study, 120 sites were seasonally sampled in a large, shallow, eutrophic lake (Taihu, China) to quantify the total bacterial (TB) and active bacterial (AB) abundances and explore their spatiotemporal distribution. Generalized additive models (GAMs) were used to identify the major environmental drivers of TB and AB dynamics. TB ranged from 7.57 × 10 4 to 1.84 × 10 8 cells mL −1 , while AB ranged from 4.42 × 10 3 to 5.56 × 10 6 cells mL −1 . The proportion of AB was significantly higher in May (mean: 18.7%; cyanobacterial bloom thriving season) than in January or September (6.8% and 4.7%, respectively). GAMs indicated that dissolved oxygen, total dissolved nitrogen (TDN), total dissolved phosphorus and turbidity explained 47.8% of the TB variation, while TDN, dissolved organic carbon, water temperature and total phosphorus explained 72.7% of the AB variation. Our study showed that nutrients and physical factors are the major drivers of the TB and AB abundance variations in Lake Taihu. Bacterial responses to environmental variation were mostly non-linear. The high proportion of AB variation (72.7%) explained by environmental parameters indicates that active bacteria are more sensitive to environmental changes and could be more effective bioindicators for long-term monitoring in shallow eutrophic lakes.

Influence of E-beam irradiation on microbiological and physicochemical properties and fatty acid profile of frozen duck meat.

This study investigated the effect of different doses (0, 3, and 7 kGy) of e‐beam on the microbiological and physicochemical qualities and the profile of fatty acids of the frozen duck meat (FDM). Electron beam at the dose of 3 kGy showed more than 2 log and 1 log cycles of reduction in the total bacterial (TAB) and coliform counts (TCC), respectively. The results indicated an increase in the TBARS values (1.50 ± 0.02 mg MDA/kg), peroxide value (0.83 ± 0.04 meq peroxide/kg), and total volatile base nitrogen (1.31 ± 0.16 mg/100 ml), but no effect on the sensory parameters. Irradiation lowered the lightness (L*) (31.87 ± 0.98) and redness (a*) (11.04 ± 0.20) values but elevated the metmyoglobin content in FDM. In addition, irradiation had no effect on the benzopyrene content; however, a reduction was observed in the vitamin A (0.239 ± 0.015 µg/g) and vitamin E (1.847 ± 0.075 µg/g) contents of the FDM samples. There were no trans‐fatty acids present in the treated (irradiated) as well as the untreated (nonirradiated) meat samples (FDM), whereas the fatty acid content decreased in irradiated samples, in contrast with the nonirradiated control. Electronic nose clearly discriminated between the nonirradiated and irradiated FDM based on principal component analysis. It is concluded that the e‐beam successfully improved the microbial quality of FDM with slight changes in physicochemical properties, but without altering its sensory properties.

Rapid Multiplex Real-Time PCR Method for the Detection and Quantification of Selected Cariogenic and Periodontal Bacteria.

Dental caries and periodontal diseases are associated with a shift from symbiotic microbiota to dysbiosis. The aim of our study was to develop a rapid, sensitive, and economical method for the identification and quantification of selected cariogenic and periodontal oral bacteria. Original protocols were designed for three real-time multiplex PCR assays to detect and quantify the ratio of 10 bacterial species associated with dental caries (“cariogenic” complex) or periodontal diseases (red complex, orange complex, and Aggregatibacter actinomycetemcomitans). A total number of 60 samples from 30 children aged 2–6 years with severe early childhood caries and gingivitis were tested. In multiplex assays, the quantification of total bacterial (TB) content for cariogenic bacteria and red complex to eliminate differences in quantities caused by specimen collection was included. The mean counts for the TB load and that of ten evaluated specimens corresponded to previously published results. We found a significant difference between the microbial compositions obtained from the area of control and the affected teeth (p < 0.05). Based on this comprehensive microbiological examination, the risk of dental caries or periodontal inflammation may be determined. The test could also be used as a tool for behavioral intervention and thus prevention of the above-mentioned diseases.

Monitoring of Dynamic Fluctuations in Microbiological and Bio-Physico-Chemical Properties of Multi-Functional Inoculated Triad Organic Mixtures during Different Aerobic Composting Systems

Monitoring of Dynamic Fluctuations in Microbiological and Bio-Physico-Chemical Properties of Multi-Functional Inoculated Triad Organic Mixtures during Different Aerobic Composting Systems

Comparative immunostimulatory effect of probiotics and prebiotics in Channa punctatus against Aphanomyces invadans

In aquaculture and human health care probiotics and prebiotics have been widely used due to their important role in enhancing beneficial gut microbiota, promoting growth, increasing disease resistance, and positively modulating the host immune system. This study reports for the first time a comparative analysis on the effect of the probiotics and prebiotics on growth, digestive enzymes activity, antioxidant activity, and immune response in Channa punctatus against Aphanomyces invadans. Among the diets enriched with Saccharomyces cerevisiae (S. cerevisiae) and Galactooligosaccharide (GOS) in C. punctatus, feeding 2.5 g kg−1 diet did not significantly influence the mean weight gain (MWG) between weeks 2 and 4 in both the infected and control groups; however the increase in MWG became significant from weeks 6–8. Similarly, during this period the protein efficiency ratio (PER), feed conversion ratio (FCR) and protein intake (PI) did not increase significantly. The intestinal protease, lipase, and amylase enzyme activities also did not increase significantly between weeks 2 and 4, whereas the values increased significantly after 6 weeks in both groups when fed with dietary supplementation of S. cerevisiae and GOS. The total S. cerevisiae count significantly increased in the gut of infected and non-infected fish fed with S. cerevisiae and GOS diets while the total bacterial (TB) count decreased between weeks 6 and 8. The total superoxide dismutase (t-SOD) activity and the malonaldehyde (MDA) concentration increased significantly in the non-infected fish fed with S. cerevisiae and GOS supplementation diets between weeks 6 and 8 whereas the catalase (CAT) and glutathione peroxidase (GPx) activities increased significantly only on week 8. The innate immune parameters such as plasma lysozyme, acid phosphatase (ACP), and myeloperoxidase (MPO) activities increased significantly in the infected and non-infected fish fed with S. cerevisiae and GOS containing diets after 6 weeks. Similarly, the plasma nitric oxide (NO) level and total protein (TP) content significantly increased in the non-infected fish fed with S. cerevisiae and GOS containing diets between weeks 6 and 8. In the control and the non-infected fish fed with S. cerevisiae and GOS enriched diets caused no mortality whereas 15% and 10% mortality was observed in the infected fish fed with S. cerevisiae and GOS diets, respectively. This study indicates that the infected and non-infected C. punctatus fed with dietary supplementation of GOS diet at 2.5 g kg−1 had exhibited better growth performance, digestive enzyme activities, gut microbiota composition, and immune response than that of S. cerevisiae diet.

Effect of diets supplemented with feed additives on growth, feed utilization, survival, body composition and intestinal bacterial load of early weaning European seabass, Dicentrarchus labrax post-larvae

The present study was carried out to evaluate the effect of supplementation of Garlen®, Diamond V XPC®, and Bactozyme® and their combination in the diets of European sea bass, Dicentrarchus labrax larvae development in hatcheries on feed intake, growth performance, feed efficiency, intestinal bacterial, survival rate, and economics analysis. Dicentrarchus labrax juveniles (1.4 ± 0.5 mg) were distributed into eight experimental groups with a density of 2.5 larvae per liter. Eight iso-nitrogenous (55% crude protein) and iso-caloric (19.2 ± 0.2 MJ/kg, DM) weaning diets were formulated to contain the control diet (no feed additives), individually or mixed alternatively with three feed additives (Garlen®; Diamond V XPC®, and Bactozyme®). Each experimental diet was allocated to three tanks of fish and fed for 12 weeks. Growth and survival rate (S %) were improved for larvae fed the diets supplied with either (Diamond V XPC® + Bactozyme®) or (Garlen® + Diamond V XPC® + Bactozyme®), respectively compared to the control larvae group. The best FCR value was recorded for larvae fed a diet supply with (Garlen® + Diamond V XPC® + Bactozyme®), while the control larvae group recorded the worst FCR. The optimum significant (P ≤ 0.05) nutrient utilization values, larvae body crude protein content, activity test (ATV%), and profit index (PI) values were observed for larvae fed a diet containing Diamond V XPC® + Bactozyme® or Garlen® + Diamond V XPC + Bactozyme® compared to other treatments. The opposite trend was observed for total bacterial (TBC) and Vibrio sp. counts. No significant (P ≥ 0.01) difference was recorded in Aeromonas sp. count values in all experimental treatments. The results from this study show that (Garlen®; Diamond V XPC®, and Bactozyme®) individually or mixed alternately as growth promoters and immune stimulants in early weaning larval diets of European sea bass under hatchery conditions led to improve growth performance, feed utilization, survival, lowest intestinal bacterial load, and highest profit index (LE).

Seasonal Variations of Raw Milk Hygienic Quality in Saudi Arabia Dairy Herds

This study was conducted to evaluate current bacterial quality of raw milk in Saudi Arabia dairy farms, to determine correlation among milk quality tests and to investigate seasonal variations in raw milk bacterial counts. Farm records on bacterial quality of raw milk were obtained from one of the largest dairy processor in Saudi Arabia over one year period (January to December 2013). Bulk tank milk samples were tested for total bacterial (TBC), coliform (CC) and laboratory pasteurization (LPC) counts by dairy plant on daily basis. The results showed that the mean and median values were 5,234 and 1,700 cfu/ml for TBC, 738 and 160 cfu/ml for CC, and 87 and 11 cfu/ml for LPC, respectively. There was low to moderate correlation among bacterial counts, indicating different sources of contamination. Seasonal data indicate higher counts during late fall and early winter compared to other months. In conclusion, this study provide insight on the current level of raw milk bacterial quality in Saudi Arabia and emphasize the importance of using multiple quality parameters for evaluation of raw milk hygienic quality.

Changes in bacterial communities by post-emergent herbicides in an Andisol fertilized with urea as revealed by DGGE

Large amounts of urea and various herbicides are applied to Chilean Andisols by farmers; however, how different herbicide types affect bacterial communities in urea-fertilized soils remains unknown. In this study, the effect of post-emergent herbicides (MCPA, flumetsulam, fluroxypyr, triclopyr, clopyralid and picloram) on total bacterial (TB) and ammonia-oxidizing bacteria (AOB) communities was investigated in a urea-fertilized soil microcosm using denaturing gradient gel electrophoresis at days 1 and 15 of incubation. The residual concentrations of herbicides in microcosm soils were measured by high-performance liquid chromatography. Differences in bacterial communities were analyzed and visualized with non-metric multidimensional scaling. All of the tested herbicides decreased in microcosm soils, reaching 46–98% of dissipation at 15days. Changes in the TB and AOB communities were variable, depending on the urea and herbicide dosage, herbicide type and sampling time. Under the recommended dose of urea (570mgkg−1 soil), soils that were treated with MCPA and triclopyr showed significant changes in TB and AOB community structures compared to control soils at both sampling times. When a 2-fold-higher recommended dose of urea (1140mgkg−1 soil) was applied, the TB communities were mainly affected by flumetsulam and picloram at both sampling times. Changes in the AOB communities were mainly observed in soils that were treated with MCPA and fluroxypyr under both urea doses. This study determined which herbicides (and doses) significantly affect the bacterial communities in urea-fertilized soils. This evidence can be very useful when management practices are being designed, revised and/or established in Andisols.

Optimization of ultrasound-induced inactivation of model bacterial mixture using response surface methodology

Ultrasound (US)-based disinfection involves the disruption of cell membranes, oxidation of active free radicals, as well as hotspot heating, either individually or in combination. Various factors can affect US efficiency for inactivating microbes. However, only a few studies have discussed the use of US for microbial inactivation via response surface methodology. Here, we evaluated the potential of US for the disinfection of water supply or the elimination of drinking water residues. Moreover, the effects of US inactivation parameters, such as energy density, sonication time, and US device duty cycle on reduction in total bacterial (TB) count and total coliform (TC) count were investigated and optimized. The results indicated that the optimal inactivation condition was achieved at an energy density of 8.30 W/mL, a sonication time of 950 s, and a duty cycle of 0.7:0.3. Under optimal conditions, the experimental values of TB and TC inactivation efficiency were 47.26% ± 4.35% and 39.23% ± 2.27%, respectively, while the predicted values were 46.57% and 38.65%, respectively. The models developed here helped to predict the effectiveness of inactivation efficiency to a ‘sufficiently applicable’ extent. Under the optimized conditions, US has high potential as an effective disinfection method, as shown by energy efficiency analysis.

Effect of farm characteristics and practices on hygienic quality of ovine raw milk used for artisan cheese production in central Italy.

A survey on ovine dairy farms directly transforming own-produced milk, in the Italian Marche region, was carried out to assess flock and milking practices that may influence milk hygienic-sanitary conditions. A census survey established that 24 dairy farms were located in this region. Bulk milk samples were collected throughout the milking period in each dairy farm in 2013. Analyzed variables were: (i) chemical parameters such as fat, protein and lactose content, dry matter and pH; and (ii) total bacterial (TBC) and somatic cell counts (SCC). Chemical parameter values were in agreement with published data while, geometric mean (GM) log10 SCC was 5.91 and TBC GM was 57 978 colony forming units/mL, in compliance with Eropean Union criteria. A positive correlation was found between SCC and TBC when GMs of all farm data were considered (Spearman's rho = 0.7925; P = 0.0001). Statistical analysis did not show significant correlation between SCC or TBC GM and dairy farm principal characteristics. Although SCC levels detected in the present study should suggest the need to implement mastitis control programs, Marche's dairy sheep flocks revealed a good hygienic condition level. This is an important aspect in implementing safety for end users of the final product.

Handling Practices and Safety of Street-Vended Milk in and Around Addis Ababa City

Forty five milk producers (MP) and 45 street-vendors (SV) of milk were selected randomly from three locations (Kotebe, Bishoftu and Chancho), Ethiopia and interviewed using semi-structured questionnaire. A total of 30 samples purposively selected from MP (15) and SV (15) were used for milk quality determinations. Milk producers in the study area generally followed unhygienic milking and improper milk handling practices. Average total bacterial (TBC) and coliform counts (CC) of milk from SV were 8.69 ± 0.15 and 6.61 ± 0.16 log10 cfu/ml and from MP the corresponding values were 6.98 + 0.15 and 4.88 ± 0.16 log10 cfu/ml, respectively. TBC and CC of milk samples obtained from streetvendors were significantly (P < 0.05) higher (1.71 and 1.73 log units, respectively) than milk samples obtained from dairy farmers. Dominant microflora isolated from raw milk belonged to the genera Bacillus (11.7%), Micrococcus (8.3%), Pseudomonas (7.8%), Staphylococcus (24.4%), Streptococcus (5%) and family Enterobacteriaceae (lactose- (32.8%) and non-lactose fermentative (10%)). The results showed poor hygienic quality of milk that may pose public health hazards. This calls for milk quality and safety improvement in the study area. Keywords: Ethiopia, hygiene, milk handling, safety, street-vended milk.

Pickling and storage of caperberries ( Capparis spp.)

Caperberries (0.7–1.9 cm diameter), collected in June 1996, were pickled for 1 month in 5% and 10% brine. Some physical, chemical and microbiological analyses were made during their fermentation and storage. While lactic acid bacteria (LAB) increased during fermentation in 5% brine, they did not increase after 15 days in 10% brine. In some cases, total bacterial (TB) growth decreased. In both brines, yeasts/moulds and coliforms (except for 5% brine on day 15) were not present after 15 and 20 days, respectively. For both caper species, the most suitable salt concentration, for LAB activity was 5–10% NaCl, and the best length of fermentation with respect to product colour, flavour, acidity, pH and LAB activity in brine was 20–25 days. The texture was maintained well during storage. Acidity and pH were markedly affected by the concentration of brine. The quality of all samples was maintained with a 15% concentration of old or fresh brine during storage. The colour of the samples, especially those of C. ovata, stored with old brine was darker that of fresh berries. As no "off" flavour was observed, it was concluded that pickled caper berries can be stored in fresh brine with a 15% NaCl concentration.