Mean Aerobic Mesophilic Counts Research Articles

Some chemical, physical, microbiological and sensorial properties of traditional water buffalo yogurts produced in Turkey

In this study, it was aimed to determine some physical, chemical, microbiological and sensorial properties of yogurts traditionally made from water buffalo milk in the Western Black Sea Region (WBSR) in Turkey. Totally 86 yogurt samples were collected from producers or sellers in the cities of Kastamonu, Karabük, Bartın, Zonguldak, Düzce and Boluin WBSR and analyzed. As a result of the analysis, mean dry matter (%), fat (%), non-fat dry matter (%), protein (%), ash (%), lactose (%), pH, acidity (LA, %), color values L*, a* and b*were obtained as 17.13±3.524, 6.98±2.327, 9.92±1.362, 4.48±0.690, 0.84±0.102, 4.59±1.011, 4.20±0.208, 1.22±0.236,96.22±2.217, -3.30±0.412 and 8.50±1.513, respectively. Starch was determined in none of the samples. Average water holding capacity was 67.48±9.594% and viscosity was 1249.67±1077.762 mPa.s. In addition; firmness (g), consistency (g.sec), cohesiveness (g) and index of viscosity (g.sec) were found as 246.43±138.898, 4910.66±2234.522, 182.32±87.672 and 334.79±149.087, respectively. Acetaldehyde, ethanol, diacetyl, acetoin and aceton values were obtained as 8.93±4.205, 114.93±154.807, 0.95±0.014, 24.44±16.905 and 0.59±0.504 (mg/kg), respectively. Mean aerobic mesophilic count was found as 4.41±1.032 log cfu/g, coliforms as 2.37±1.077 log cfu/g, yeasts and molds as 4.16±1.076 log cfu/g and total lactic acid bacteria count as 5.96±0.923 log cfu/g. Sensorial analyses showed that average appearance score was 3.76±1.005, smell 4.03±0.978, taste 3.64±1.105, consistency by spoon 3.93±1.005 and consistency by mouth3.71±1.022 on scale 5. Important variations in properties analyzed were observed among the samples collected from different cities. For example, the values of dry matter, fat, protein, ash, water holding capacity, viscosity and color were the highest in the samples of Karabük city among the others.

Reduction potential of steam vacuum and high-pressure water treatment on microbes during beef meat processing

In order to assess the reduction potential of steam vacuum treatment (SVT) and high-pressure water treatment (HPWT) to reduce microbial contamination during beef processing, ten randomly selected carcass halves and effluents were evaluated using microbiological reference methods and quantitative real-time PCR (qPCR). While SVT was applied after evisceration, HPWT was applied prior to carcass storage in a cooling room. The SVT showed no statistically significant reduction of aerobic mesophilic counts (AMC) or Enterobacteriaceae counts, although Pseudomonadaceae counts were slightly reduced on the surface of the carcasses. In contrast, HPWT caused a significant increase in the mean AMC and Pseudomonadaceae counts by 0.80 (5.3-fold increase) and 0.77 (5.9-fold increase) log10 CFU/cm2, respectively. As for total bacterial cell equivalents (BCE) using the 16s rRNA gene, the SVT caused a significant reduction of 0.70 log10 BCE/cm2 (0.8-fold decrease), whereas the HPWT caused a significant increase of 0.19 log10 BCE/cm2 (0.6-fold increase). When targeting C. jejuni, SVT appeared to have no impact on the C. jejuni cell equivalents (CJE), but there was a slight increase of 0.22 log10 CJE/cm2 (0.7-fold) observed with the use of HPWT. Overall, short exposure (10 s) to the HPWT had no effect in reducing contamination and rather posed a risk of introducing water- or airborne contaminants. In principle, SVT may be useful in reducing microbial contamination for the carcass site tested, but the effect should be interpreted as a part of the entire Hazard Analysis and Critical Control Point (HACCP) plan. Furthermore, we suggest the continued use of a combination of culture-based and culture-independent molecular techniques to get a more complete picture of the efficacy of specific beef carcass decontamination techniques.

Bacteriological quality and safety of green pepper and tomato irrigated with Abay River water in Bahir Dar town

The objective of this study was to determine the bacteriological quality and safety of green pepper (Capsicum annuum) and tomato (Lycopersicon esculentum) grown along Abay river of Bahir Dar town, Ethiopia. The mean aerobic mesophilic counts from tomato and green pepper were 4.72 and 5.01 respectively. The mean total coliform counts from tomato was 234.9 MPN/g and green pepper 303.2 MPN/g. Similarly, the mean fecal coliform counts of tomato was 45.08 MPN/g and 58.1MPN/g from green pepper. The mean bacterial counts of green pepper were higher than tomato vegetables. Moreover, 5 (8.3%) Salmonella, 3 (5%) Shigella spp. and 6 (10% ) E. coli spp. were isolated from tomato; and 6 (10%) Salmonella, 5 (8.3%) Shigella and 9 (15%) E. coli spp. were detected from green pepper samples. The mean total coliform counts from Bezawit were 1040 MPN/100ml and 711.67MPN/100ml Gudguad site. Similarly, the mean fecal coliform counts of Bezawit was 689.67MPN/100ml and 390.00MPN/100ml from Gudguad. In both sites, lack of awareness and poor irrigation practice promote the probability of vegetable contamination. Therefore, keeping the irrigation practice of irrigated vegetable and providing regular training for farmers are some of the practices to improve bacteriological quality, safety and shelflife of vegetables and their products.

Salmonella spp. and risk factors for the contamination of slaughtered cattle carcass from a slaughterhouse of Bahir Dar Town, Ethiopia

ObjectiveTo assess the prevalence of Salmonella species and associated factors from cattle carcasses in abattoir of Bahir Dar, Ethiopia. MethodsA cross-sectional study was conducted among slaughtered cattle carcass samples from Bahir Dar abattoir from December 2012 to February 2013. A total of 300 carcasses from hind limb, abdomen and neck of one hundred cattle were collected and analyzed for the prevalence of Salmonella. An observation checklist was used to collect data on the risk factors for contamination of carcass. ResultsOut of the total 300 carcass samples, 23 (7.6%) were positive for Salmonella species. Eleven (47.8%), nine (39.1%) and three (13.1%) of the isolates were Salmonella group A, Salmonella arizonae and Salmonella typhi, respectively. Wearing garment during slaughtering, hand-washing after separating intestinal content, washing of the knife before slaughtering, slaughtering on sanitized floor and carcass-washing during slaughter were important risk factors that have statistically significant association with the isolation rate of Salmonella in slaughtered cattle carcasses (P<0.05). The mean aerobic mesophilic count of cattle carcass surfaces was 5.39 log CFU/cm2. ConclusionsUnlike other studies, Salmonella group A appears to be the most prevalent species in cattle carcasses in the present study. Among carcass sites, the highest contamination was recorded in the abdomen and the main source of contamination is human and intestinal contents. Therefore, there is a need to maintain proper hygienic practices in Bahir Dar abattoir during slaughtering.

Evaluation of the Microbiological Quality of Conventional and Organic Leafy Greens at the Time of Purchase from Retail Markets in Alexandria, Egypt

This is a pioneer study in Egypt that provides some assessment of the microbiological quality of conventional and organic leafy green vegetables that constitute an essential component of the Egyptians' daily diet. A total of 380 samples of unpackaged whole conventional and 84 packaged whole organic leafy greens were collected from retail markets in Alexandria, and analyzed for total aerobic mesophilic count (AMC) and total E. coli count (ECC) using the standard spread plate method. Mean AMC values for organic samples were statistically less (p < 0.05) than those of the corresponding conventional samples. Conventional radish and organic parsley samples had the highest AMC of 7.17 and 7.68 log CFU/g respectively, while conventional green cabbage and organic basil had the lowest AMC of 3.63 and 3.23 log CFU/g respectively. The presence of E. coli in 100% of the studied leafy greens was indicative of potential fecal contamination, in view of open and unhygienic environmental and unsanitary handling conditions, as leafy green items are available for sale by street-vendors. Unsatisfactory AMC and ECC levels encountered in the studied samples, warrant future investigations to determine the potential prevalence of foodborne pathogens, and to identify sources of dominating microorganisms, which could make a contribution to the field of food safety

Microbiological quality of fresh lettuce from organic and conventional production

Previously there was no available information on the levels of indicator bacteria and the prevalence of pathogens in fresh lettuce grown in organic and conventional farms in Spain. A total of 72 lettuce samples (18 farms for 4 repetitions each) for each type of the agriculture were examined in order to assess the bacteriological quality of the lettuces, in particular the prevalence of selected pathogens. The lettuce samples were analyzed for the presence of aerobic mesophilic, psychrotrophic microorganisms, yeasts and moulds, Enterobacteriaceae, mesophilic lactic acid bacteria, Pseudomonas spp. and presumptive Escherichia coli, Salmonella spp. and Listeria monocytogenes. The mean aerobic mesophilic counts (AM) were 6.35 ± 0.69 log 10 cfu g −1 and 5.67 ± 0.80 log 10 cfu g −1 from organic and conventional lettuce, respectively. The mean counts of psychrotrophic microorganisms were 5.82 ± 1.01 log 10 cfu g −1 and 5.41 ± 0.92 log 10 cfu g −1 from organic and conventional lettuce, respectively. Yeasts and moulds (YM) mean counts were 4.74 ± 0.83 log 10 cfu g −1 and 4.21 ± 0.96 log 10 cfu g −1 from organic and conventional lettuce, respectively. Lactic acid bacteria (LAB) were present in low numbers and the mean counts were 2.41 ± 1.10 log 10 cfu g −1 and 1.99 ± 0.91 log 10 cfu g −1 from organic and conventional lettuce, respectively. Pseudomonas spp. mean counts were 5.49 ± 1.37 log 10 cfu g −1 and 4.98 ± 1.26 log 10 cfu g −1 in organic and conventional lettuce, respectively. The mean counts for Enterobacteriaceae were 5.16 ± 1.01 log 10 cfu g −1 and 3.80 ± 1.53 log 10 cfu g −1 in organic and conventional lettuce, respectively. E. coli was detected in 22.2% (16 samples) of organic lettuce and in 12.5% (9 samples) of conventional lettuce. None of the lettuce samples was positive for E. coli O157:H7, L. monocytogenes and Salmonella spp. From the samples analyzed by principal component analysis (PCA) a pattern with two different groups (conventional and organic) can be observed, being the highest difference between both kinds of samples the Enterobacteriaceae count.

Microbiological Quality of Rabbit Meat

World rabbit meat production is estimated to be over 1 million tons, and Spain is the third largest producer. Although rabbit meat is marketed and consumed worldwide, information on microbiological quality is very scarce. Here, we report indicator organisms, spoilage flora, sensory quality, and some physicochemical traits of 24 h postmortem chilled rabbit carcasses and prepackaged rabbit meat stored chilled in air for 0 to 3 days at the retail level. The mean total bacterial count (4.01±0.48 log CFU/g) for carcasses dressed at a small abattoir by a manual process was significantly lower (P < 0.05) than that (4.96±0.90 log CFU/g) for carcasses dressed at a large abattoir in automated slaughter lines. Both groups of carcasses had mean pH values of 5.98. The dominant contaminants on carcasses from the small abattoir were Pseudomonas, lactic acid bacteria, and yeasts. These microorganisms and Brochothrix thermosphacta were dominant on carcasses from the large abattoir. On prepacked hind legs (pH 6.26 ± 0.18) stored at −1 to + 1° C (supermarket 1), mean aerobic mesophilic count was 5.87±1.03 log CFU/g, and the major microbial groups were Pseudomonas, yeasts, lactic acid bacteria, and B. thermosphacta. On prepacked whole carcasses (pH 6.37 ± 0.18) displayed at −1 to + 5° C (supermarket 2), mean aerobic mesophilic count was 6.60±1.18 and the same microbial groups were dominant. Relative Escherichia coli incidence was supermarket 2 > large abattoir > supermarket 1 > small abattoir. Overall, low numbers of coliforms, Enterobacteriaceae, psychrotrophic clostridia, coagulase-positive staphylococci, and molds were found. Sensory scores, pH values, and L-lactic acid content differentiated fresh carcasses from retail samples. Data obtained suggest that the microflora of chilled rabbit meat are different from those found on the meat of other animals.

Microbial flora and some chemical properties of ersho, a starter for teff (Eragrostis tef) fermentation

Ersho is a clear, yellow liquid that accumulates on the surface of fermenting teff-flour batter and is collected to serve as an inoculum for the next fermentation. The pH of ersho samples was about 3.5 and titratable acidity ranged between 3.1% and 5.7%. The mean aerobic mesophilic counts from four households varied between 6.9×10(6) and 1.3×10(8) c.f.u./ml and the aerobic bacterial flora consisted of Bacillus spp. Mean yeast counts ranged between 5.2×10(5) and 1.8×10(6) c.f.u./ml and comprised, in order of abundance, Candida milleri, Rhodotorula mucilaginosa, Kluyveromyces marxianus, Pichia naganishii and Debaromyces hansenii. Candida milleri was the most dominant isolate in all samples. About 90% of the teff flour samples had aerobic mesophilic counts ≥10(5) c.f.u./g and Gram-positive bacteria constituted about 71% of the total isolates. About 80% of samples had Enterobacteriaceae counts of 10(4) c.f.u./g.