Standard Plate Count Research Articles

Rapid Detection of the Activity of Lacticaseibacillus Casei Zhang by Flow Cytometry

Food processing, e.g., freeze-drying, exerts strong pressure on bacteria in the food matrix, decreasing their viability/activity and even forcing them to become viable but unculturable (VBNC), which are often underestimated by traditional plate count. The strict standards of bacterial viability in probiotic products require accurate cell viability/activity enumeration. We developed a staining (5(6)-carboxyfluorescein diacetate succinimide ester, propidium iodide)-based flow cytometry rapid method for detecting the viability/activity of Lacticaseibacillus (Lb.) casei Zhang, a widely used probiotic in the dairy industry in China. We optimized the procedural and instrumental parameters for generating results comparable to that of standard plate counts. This method was also applied to freeze-dried Lb. casei Zhang, yielding 7.7 × 1011 CFU/g, which was non-significantly higher than the results obtained by plate count (6.4 × 1011 CFU/g), possibly due to the detection of VBNC cells in the freeze-dried powder. We anticipated that this method can be used for detecting lactic acid bacteria in other probiotic food/beverages.

Detection and Molecular Characterization of Some Virulence Genes of Escherichia Coli Isolated from Milk in Dairy Cow Farms

Coliform pathogens, primarily E. coli, were discovered throughout the farm, causing environmental mastitis and can be shed from the udder into the milk; they are concerned about severe gastrointestinal disruption and potential enteropathogenic and/or toxic strains, posing a risk to public health. The objectives of this study were to identify the incidence and harmful serotypes of pathogenic Escherichiacoliand some of their virulent genes, which were isolated from the collected milk of some dairy farms in the Delta region and Cairo-Alexandria desert road farms, in Egypt during one year using the polymerase chain reaction (PCR) technique after bacteriological and serological identification as well as determine the antimicrobial susceptibility of the isolated strains. 150 milk samples in total were gathered (100 milk samples from bulk milk tanks and the other 50 samples from clinically mastitic dairy cows). According to our finding, the mean values of somatic cell count (SCC), standard plate count (SPC), and coliform count (CC) in the hundred bulk tank milk samples were 3.67 1.08×104/ml, 7.08×104± 6.25×104 cfu/ml and 3.04×102±1.43×102/ml, respectively. The bacteriological investigation exhibited that, the Escherichiacoli incidences from bulk tank milk (BTM) and mastitic milk samples (MMS) were 12% and 18%, respectively. The detected E.coli serotypes including, O26, O44, O55:K99, O111, O119 and O157:H7 from MMS, while O1, O55, O78, O86, O124 and O158:H10 from BTM. Molecular virulence characterization of E.coli strains showed that, Shiga toxins 2 (stx2) gene is present in O157:H7, while the stx1 gene present in O26. The Intimin gene (eaeA) is involved in four strains, O44, O111, O119, and O157:H7. Positive amplification of a biofilm gene (adrA) appeared in all E.coli strains. The outcome of the antimicrobial susceptibility revealed high resistance to amoxicillin (85.71%), streptomycin (80.95%), ampicillin (71.43%), and flucloxacillin (61.90%). Meanwhile, the highest susceptibility was to ciprofloxacin (95.24%) followed by enrofloxacin (90.48%), neomycin (80.95%), and gentamycin (76.19%). Effective hygienic measurements are required to avoid toxigenic and pathogenic E.coli and more future studies should be performed to increase awareness in dairy farms.

Storage studies on Low calorieburfi incorporated with Sucralose and Costusspeciosus extract

In the present study, changes in compositional, physico-chemical, sensory and microbial properties (SPC, coliform count and yeast and mould count) of low calorie burfi packed in low density polyethylene (LDPE) film was monitored. The changes were studied at 37 ± 1ºC and 4±1ºC on every 7th day of storage till the products became unacceptable. The sucralose content in low calorie burfi was estimated and found to be 150ppm. The pH was found to significantly (p<0.05) decreased during the storage period whereas acidity, FFA, TBA value and solublenitrogen contents increased significantly (p<0.05). The standard plate counts and yeast and mould counts were found to increased progressively during storage whereas coliform count was absent in the product throughout the storage period. Shelf life study showed that developed low calorie burfi had a shelf life of 20days under refrigeration and 7 days at ambient temperature.

Evalution of Jeevamrutham (Organic Biofertilizer) for It’s use in the Devising an Nutrient Medium for the Isolation of Bacteria

Jeevamrutham is widely used Organic biofertilizer prepared with cow waste, gram flour and Jaggery by fermentation process. The study was aimed at physicochemical and microbiological analysis of jeevamrutham and also to evaluate it’s use as a nutrient medium for isolation of bacteria. The Jeevamrutham prepared and subjected to physicochemical, and microbiological analysis. The filtrate of the Jeevamrutham was studied for its use as a Nutrient (Jeevamrut) medium for the growth of the bacteria. Total solid content of Jeevamrutham was found to be 100 mg/ml. The Standard Plate count (SPC) for Nitrogen fixers, for Phosphate solubilizing bacteria was found to be maximum on 6th day of fermentation. The SPC for Yeast and Molds was found to be maximum on 8th day. The study regarding the evaluation of Jeevamrut medium showed excellent growth of test Gram positive and Gram negative bacteria on Jeevamrut medium. The pigment producers showed same pigmentation pattern on Jeevamrut agar and on conventially used Nutrient agar. The cost of the Jeevamrut medium was calculated per 100 ml of medium and was found to be 60.27% less than that of commercially available media. The Jeevamrut medium is economical, all the ingredients are easily available, cheap and ecofriendly. The Jeevamrut medium can be a best option to use as a Nutrient medium for the cultivation of bacteria in the laboratory

Effect of vacuum packaging on the physicochemical and shelf life attributes of herbal paneer spread

A study was conducted to assess the impact of vacuum packaging during storage for herbal paneer spread. Paneer spread incorporated with Aloevera and Tulsi extract (1% each) was packed and stored in normal and vacuum package (LDPE pouch) at refrigerated temperature (5±1ºc) and analysis were done at 5 days interval. The product was analysed for its Physicochemical studies and shelf-life attributes were examined during storage by microbial analysis like standard plate count and coliform count. The paneer spread with herbal extract stored in vacuum packaging have more functional properties and shelf-life than normal packaging. The efficiency of vacuum packaging is good by removing more moisture content than normal packaging therefore it increased the shelf life of the herbal paneer spread by 50% (approximately) as compared with normal packaging at refrigerated storage.

Development and characterization of herbal Kulfi (Ice Cream) using Tulsi, Ginger,and Clove

Herbs and spices are used for imparting flavor, thearoma of the products and also possess various therapeutic properties like anti-stress, anti-hypertensive, anti-tumor, anti-oxidant, anti-microbial, and anti-inflammatory properties. The present study was aimed to develop herbal kulfi using tulsi paste, ginger juice, and clove extract and the effects of the addition of herbs on its compositional, physicochemical properties, nutritional parameters, sensory attributes, and microbial quality. Initial trials were conducted to adjudge the most acceptable levelsusing tulsi paste (2.5%, 5.0% and 7.5%), ginger juice (2.0%, 3.0%and 4.0%) and clove extract (2.0%, 3.0% and 4.0%). An optimized herbal kulfi was developed using 2.5% tulsi paste, 2.0% ginger juice, and 4.0% clove extract. The kulfi prepared without anyaddition of tulsi, ginger, and clove was treated as control. The optimized herbal kulfi reported a fat content of 12.0%, protein3.53 %, total solids 42.80%, ash 1.0233%, carbohydrate 23.04%.The developed herbal kulfi reported 10.01% anti-oxidant activity and total phenolic content of 56.96 mg GAE/100g. The products possess a good level of anti-oxidant and total phenolic content. The herbal kulfi conforms to the FSSA requirements for ‘kulfi’. The standard plate count was found 3.85 cfu/g. The yeast andmold and coliform count were absent in the product as per FSSA standard.

Cumin oil as a natural preservative for prolonging shelf-life of chicken meat emulsion at refrigeration temperature

Context Cumin is a common spice used for enhancement of flavour. Its preservative potential as a natural antioxidant and antimicrobial agent in meat model system might extend its use as an alternative to synthetic/chemical preservatives, which are widely used in meat products. Aims The present study aims at exploring cumin essential oil as a natural preservative in meat model system. Methods Four groups consisting of a control (C) and treatments (T0.5, T0.75 and T1.0) with added cumin essential oil were prepared as C, control without cumin oil, T0.5 with 0.50% cumin oil w/w; T0.75 with 0.75% cumin oil w/w and T1.0 with 1.0% cumin oil w/w and were stored at refrigeration for 12 days in aerobic packaging. The effect of cumin oil on physicochemical, antioxidant, lipid oxidation, microbial and sensory quality of meat emulsions were analysed on every third day. Key results The results showed that pH, titratable acidity, emulsion stability and extract release volume values were higher (P < 0.05) in oil-treated groups. Total phenolic content (TPC), 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (DPPH) and 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS+) radical scavenging activity (ABTS) % inhibition value were also higher in meat emulsion with added cumin oil treated groups than in control, and free-radical scavenging efficacy increased in dose–dependent manner. The meat emulsions added with cumin oil evinced a lower peroxide value, and thiobarbituric acid reactive substance (TBARS) and free fatty acid (FFA) concentrations than in control. The T1.0 of all showed (P < 0.05) a lower rate of microbial proliferation standard plate count (SPC), psychrophilic count, coliform count and yeast and mould (Y and M) than did other groups. Sensory panelists rated T0.75 comparatively higher for colour and appearance and flavour than they did T1.0, T0.5 and control. Conclusions It could be concluded that with inclusion of cumin oil at 0.75% level in meat emulsion, the physicochemical quality and antioxidant capacity improved significantly, while lipid oxidation and microbial proliferation decreased together with acceptable sensory attributes. Implications Increasing harmful effects of chemical preservatives and growing consumer-health concerns have boosted the demand for clean label or natural preservatives. With growing market of ‘ready to cook’ meat products, good preservation with cumin essential oil would enhance its consumer appeal and marketability.

Development of cheese spread using goat milk Chakka and Guava (Psidium guajava) fruit pulp

A study was conducted to develop cheese spread from cheddar cheese (CC), goat milk chakka (GMC) and guava fruit pulp (GFP). The proportion of CC and GMC were chosen based on preliminarily trial. Subsequently, GFP (Sardar and Basti Red varieties of guava) was incorporated @ 5% of cheese spread. With the increased level of GMC in cheese spread, fat, protein, ash and total solids contents decreased and acidity increased (P<0.05) significantly. Colour values (L* and a*) increased whereas b* decreased (P<0.05) significantly with increased level of GMC. Colour and appearance, flavour, body and texture, spreadability and overall acceptability in optimized cheese spread were 8.50±0.40, 8.66±0.02, 7.80±0.05, 7.73±0.10 and 8.23±0.05 scores, respectively. With the increased level of GFP in cheese spread, carbohydrate, ash, and total solids increased while fat and protein decreased. Fat, protein, carbohydrates, ash, total solids, acidity and vitamin C contents in optimized cheese spread were 19.47±0.04, 21.53±0.07, 3.01±0.01, 2.15±0.13, 46.18±0.11, 1.92% lactic acid and 12.73 mg/100 g, respectively. Microbial load in terms of standard plate count, and yeast and mould counts increased with increasing GFP levels in cheese spread. It was concluded that best quality cheese spread could be prepared by blending CC and GMC at 40:60 with 6% GFP of Sardar variety.

Bacteria Associated with Skin Piercing Equipment and their Antibiotic Susceptibility Pattern in Port Harcourt Metropolis

Skin Piercing is becoming rampant among adolescent in our contemporary society without considering its health implication and the risk of pathogenic microorganisms associated with equipment used. Hence, this research is carried out to determine the bacteria associated with this skin piercing equipment and their antibiotic susceptibility pattern in Port Harcourt metropolis. A total of thirty (30) skin piercing equipment were swab using sterile swab sticks and samples subjected to standard microbiological technique as well as standard plate count, culturing, identification and antibiotic susceptibility pattern using Kirby Bauer Disk diffusion method. The distributed questionnaires showed that the percentage of female (79.56%) involved in skin piercing is more than the males (20.44%). The total heterotrophic bacteria count ranged from 4.75±0.03×103 CFU/ml to 6.31±0.23×104 CFU/ml in RSU back gate and PH Victoria Street respectively. The total Staphylococcal count ranged from 1.90±0.01×102 CFU/ml to 4.31±0.03×102 CFU/ml in RSU back gate and PH Victoria Street respectively. A total of Seventeen (17) bacteria isolates were identified belonging to the following genera; Staphylococcus spp, Streptococcus spp, Bacillus spp, Micrococcus spp, and Clostridium spp. The prevalence of the bacteria indicated that Staphylococcus had the highest occurrence (26%), followed closely by Pseudomonas spp (19%), and Clostridium spp (11.7%) had the least prevalence across the locations. The Antimicrobial sensitivity testing results shows that Staphylococcus spp, Streptococcus spp, Bacillus spp, Micrococcus spp, and Clostridium spp are more susceptible to Erythromycin, Gentamicin and Ofloxacin (100%) and resistant to Augmentin, Ceftazidime, Cefuroxime and Ceftriaxone (100%) Pseudomonas spp was Susceptible to Gentamicin, Nitrofurantoin and Ciprofloxacin (100%) and resistant to Ceftazidime, Cefuroxime and Augmentin (100%). These bacteria isolated are mostly pathogenic and may result in an increase in health complication as a result of non-hygienic protocol employed during using this skin piercing equipment. Professionals should enlighten and give advisory comment to adolescent about the risks involved in skin piercing practices.

A hybrid and scalable nanofabrication approach for bio-inspired bactericidal silicon nanospike surfaces

Insects and plants exhibit bactericidal properties through surface nanostructures, such as nanospikes, which physically kill bacteria without antibiotics or chemicals. This is a promising new avenue for achieving antibacterial surfaces. However, the existing methods for fabricating nanospikes are incapable of producing uniform nanostructures on a large scale and in a cost-effective manner. In this paper, a scalable nanofabrication method involving the application of nanosphere lithography and reactive ion etching for constructing nanospike surfaces is demonstrated. Low-cost silicon nanospikes with uniform spacing that were sized similarly to biological nanospikes on cicada wings with a 4-inch wafer scale were fabricated. The spacing, tip radius, and base diameter of the silicon nanospikes were controlled precisely by adjusting the nanosphere diameters, etching conditions, and diameter reduction. The bactericidal properties of the silicon nanospikes with 300 nm spacing were measured quantitatively using the standard viability plate count method; they killed E. coli cells with 59 % efficiency within 30 h. The antibacterial ability of the nanospike surface was further indicated by the morphological differences between bacteria observed in the scanning electron microscopic images as well as the live/dead stains of fluorescence signals. The fabrication process combined the advantages of both top-down and bottom-up methods and was a significant step toward affordable bio-inspired antibacterial surfaces.

Microbial and Physicochemical Quality of Kurdish Soft Cheese in Retail Markets in Erbil

Dairy products is considered the most complete foodstuff that provide human with most of their vital needs. The aim of this study to evaluate some chemical parameters and bacteriological quality of traditional white soft cheese. Our finding indicates that, the pH ranged between 5.72 to 7.25 with an average of 6.53, moisture percentage ranged between 37.76 % to 54.95 % with an average of 45.03%, fat percentage between 1.2 % to 4.3 % with an average of 2.36 %, protein percentage ranged between 16.3 % to 23.16 % with an average of 19.55 %. Ash percentage ranged between 1.7% to 2.8% with an average of 2.20. Total solid percentage ranged between 25 % to 37.7 %with an average of 31.26 %. Acidity ranged between 1.3 % to 2.5 % with an average of 1.70 %. Salt percentage ranged between 1.4 to 4.3 with an average of 2.89 %. The standard plate count of soft cheese was detected to be the interval of 1.2 x 104 - 4.7 x106 cfu/g. In the all cheese samples the coliform bacteria count was detected to be between 4.0 x103 to 8.6 x105 cfu/g. The yeast and mold count was found to be 9.6 x10 to 3.2 x105 cfu/g. The results found 20 % of Staphylococcus aureus contaminations, 13.33 % of Salmonella spp. contaminations. Cheese produced in Erbil are not agree with the Iraqi Standard.

Quality of refrigerated raw milk according to the bulk transport conditions

Technical regulations that determine milk quality standards in Brazil establish the minimum criteria that the processing industry's raw material must present. These rules can challenge the logistics sector (transport) to maintain adequate milk conservation levels. We aimed to evaluate the influence of bulk transport and storage conditions on refrigerated raw milk quality. The experiment was carried out in a dairy industry in Santa Catarina State. Information and samples of refrigerated raw milk were collected from dairy farms, from isothermal compartments of milk trucks, and from the industry's storage silo. These samples were submitted to microbiological analysis, somatic cell count (SCC), and physicochemical analysis. The results were evaluated by ANOVA and multivariate analysis (factor analysis). The transport of raw milk in bulk and the transfer of raw material to the industrial silo worsened the milk's microbiological quality (p &lt; 0.0001) for standard plate count (SPC) and psychrotrophic microorganism count (PMC), without affecting, the physicochemical characteristics of the milk (p &gt; 0.05). Poor hygienic conditions in milk storage rooms, in the refrigeration bulk tanks of the dairy farms, and during the transport, as well as the transport on longer routes, were related to higher SPC and psychrotrophic count while receiving milk by the dairy industry with higher temperatures was only associated with higher SPC.

Effects of DNA extraction methods on the real time PCR quantification of Campylobacter jejuni, Campylobacter coli, and Campylobacter lari in chicken feces and ceca contents

Polymerase chain reaction (PCR) method was coupled with a DNA extraction to enumerate Campylobacter spp. from poultry gastrointestinal tract samples. Three experiments were conducted that included: 1) Development of a DNA standard curve related to bacterial DNA primers; 2) Design of a cell/genomic DNA extraction protocol to isolate Campylobacter spp. DNA from complex samples such as poultry feces; and 3) Comparison of PCR quantification to standard plate count methodology. The standard curve using primers for Campylobacter spp. was created for DNA extracted from environmental isolates with a linear range (R2 > 0.95) and with a high specificity for C. coli and C. jejuni recovered from poultry, swine and laboratory isolates. A 2-step extraction process of bacterial DNA from poultry feces was developed in which the cells were first concentrated using a gradient-centrifugation step followed by comparison of 4 DNA extraction methods. Two commercial DNA extraction methods (Zymo Research Quick DNA, and Invitrogen magnetic separation), a traditional phenol-chloroform DNA extraction method using proteinase K to inactivate DNAses, and an in-house isolation method for DNA extraction based on chaotropic salts were used. The middle gradient layer recovered 89% to 98% of the bacteria cells from the sample, with recovery dependent upon the Campylobacter genus. The 4 DNA extractions methods recovered 112 to 302 ug/nL of DNA. Finally, the qPCR and standard plate methods were highly correlated for enumerating Campylobacter spp. in the 2.0 to 8.0-log CFU range. Analyses of the results from this study demonstrate that the combination of the standard curve for Campylobacter spp. DNA primers, the gradient cell concentration method and DNA extraction techniques with qPCR can be used to enumerate Campylobacter spp. from poultry samples with findings similar those of traditional plate count methodology.

Prevalence and Antibiogram of Biofilm Forming Bacteria Associated with Toilet Seats in Dormitories within a University Campus in Port Harcourt, Rivers State, Nigeria

Public toilet facilities pose serious health threats to those accessing it, as they may be sources of infection to the users. Understanding the bacterial types and their virulence features such as biofilm production and resistance to antibiotics will aid in advancing control measures. This study was therefore conducted to determine the prevalence and antibiogram of biofilm forming bacterial species associated with toilet seats in University dormitories. A total of 24 samples were obtained from six (6) hostels aseptically. The samples were subjected to standard microbiological procedures for the isolation and identification of the bacterial species. Standard plate count was used for the enumeration of the bacterial populations. Antibiotics susceptibility and biofilm production was evaluated using the Kirby-Bauer disk diffusion and the Congo red agar method, respectively. The data obtained from the study identified Staphylococcus spp. as the predominant isolate, having a prevalence of 58.3%, followed by Bacillus spp. (54.2%), while Serratia mercensis (4.2%) was the least encountered isolate. Data obtained showed the total heterotrophic bacterial count ranged from 1±0.02 x 105 cfu/ml to 2.5±0.03 x 105 cfu/ml. The antibiogram obtained showed that the isolates were highly resistant to most of the antibiotics tested, as all the Gram positive isolates (100 %) were resistant to five (i.e 62.5 %) of the antibiotics (Cefuroxime, Ceftaziidime, Augmentin, Cloxacillin and Ceftriaxone). The Gram negative isolates showed similar pattern where 100 % of the isolates were resistant to four (i.e 50%) of the antibiotics, (Augmentin, Ceftaziidime, Ciprofloxacin and Cefuroxime). The results showed 57.1 % of the isolates produced biofilm. The study indicated a high rate of recovery of bacteria from the toilet seats in dormitories within the University. Proper sanitary measures should therefore be adopted to facilitate good hygiene and reduce the transmission of bacterial infections.

Microbiological quality assessment of fish origin food along the production chain in upper Blue Nile watershed, Ethiopia.

Pathogenic microorganisms can grow accidentally on fish origin human food and can be a cause of human food-borne illness. The purpose of this study was to estimate the occurrence and microbial load pattern of Escherichia coli, Salmonella, Staphylococcus aureus, and Shigella spp. along the fish origin food value chain. A total of 396 fish samples were collected by a systematic random sampling technique of cooked and raw in the three species of fish. Fish muscles were tested using selective media, followed by conventional biochemical tests. The bacterial load was assessed using a standard plate count method. Whereas the fungal load were measured by cultured in a Sabouraud's dextrose agar (SDA) medium. The overall prevalence was Escherichia coli 84 (21.21%), Salmonella 27 (6.82%), Staphylococcus aureus 19 (4.80%), and Shigella spp. 17 (4.29%). The average mean total coliform count was observed 1.2 × 102 cfu/g and 5.10 × 104 cfu/g in cooked and raw fish samples, respectively. Whereas total viable count mean of 8.05 × 104 cfu/g and 11.5 × 104 cfu/g in cooked and raw fish, respectively. The Fungal load counts under the range 5.6 × 101 cfu/g to 1.09 × 103cfu/g were observed. The study has revealed that fish food in the study area has the possibility of microbial public health risk. Hence, it could be wise to improve the knowledge of key actors from harvesting to consumption to enhance the meals protection practices and high-quality standards of fish foods.

Study the presence of tetramethylthiuram disulfide residue in three selected microgreen species

Microgreens are tender leafy vegetables which are popular among consumers due to their pleasing colors, textures, flavors, and high nutritive values. Microgreens are generally consumed fresh and in relatively large portion sizes. Tender cotyledons of carrot, beetroot, lettuce, amaranthus, cabbage etc. are popular as microgreens among local consumers at present. All most all exotic vegetable seeds found in domestic markets are treated with fungicide (Thiram: Tetramethylthiuram disulfide) thus pose a health risk. Therefore, this study was conducted to identify the presence of fungicide residue in 3 microgreen varieties Amaranthus (Amaranthus viridis; var Red Thampala), Carrot (Daucus carota subsp. sativus; var New Kurodaand and Mungbean (Vigna radiata; var MI 5). Seeds were sawn at 125 g/m2 rate on trays with a coir dust medium and 30-36 LUX light was supplied continuously. Temperature, pH and RH of the growth medium were maintained at 28–30 °C, 5.5–6.0 and 90–95% while 70–78 % RH and 30–34 °C temperature were maintained as environmental conditions. Height at harvesting of 10 – 14 days old carrot and amaranthus microgreens were 7.5 cm while that of mungbean was 14 cm. Chlorophyll content and fungicide residue were analyzed in harvested microgreens and microbial growth of growth medium was checked. Amaranthuss and carrot had 1.1 CCI and mungbean had 2.4 CCI values as average chlorophyll contents at harvesting. According to FTIR analysis thiram presented only in carrot microgreens and further quantifications are on progress. Mean results of standard plate count of growth medium were 10 CFU/ml in amaranthus and 11 CFU/ml in carrot and mungbean.

Impact of Artisanal Crude Oil Refinery on Physicochemical and Microbiological Properties of Soil and Water in Igia-Ama, Tombia Kingdom, Rivers State, Nigeria

This study aimed to determine the impact of artisanal refinery operations on the physicochemical and microbiological properties of soil and water in Igia-Ama, Tombia Kingdom, Rivers State, Nigeria. Physicochemical parameters along with concentrations of heavy metals, polyaromatic hydrocarbons (PAHs), total petroleum hydrocarbon (TPH), benzene, toluene, ethylbenzene and xylene (BTEX), and polychlorinated biphenyls (PCB) were determined in soil and water samples using standard methods. Microbial populations were determined using standard plate count. Microbial isolates were identified based on their cultural, morphological and biochemical characteristics. Results show that concentrations of monitored physicochemical parameters differed significantly (p&lt;0.05) between impacted sites and control as well as between dry and wet season. Heavy metals, PAHs, TPH, BTEX and PCB concentrations were higher in the impacted sites than in the control (significant, p&lt;0.05), and also differed significantly between dry and wet season. Microbial counts varied between polluted samples and control as well as between dry and wet season, though not significantly different (p&gt;0.05). Bacterial isolates in polluted soil samples were identified as Enterobacter sp., Bacillus sp., Micrococcus sp., Staphylococcus sp. and Pseudomonas sp. Bacteria in polluted water samples were identified as Staphylococcus sp. and Escherichia coli. Fungi in polluted soil samples were identified as Aspergillus sp., Penicillium sp. Fusarium sp., Rhodotorula sp., Exophiala sp. and Crypotococcus sp. While only Penicillium sp. was isolated in polluted water sample. Artisanal crude oil refinery operations significantly impacted the physicochemical properties of soil and water in the study area but not the microbiological properties. The levels of heavy metals, PAHs, TPH and BTEX in the soil and water suggest the need for remediation of the impacted environment.

EFFECT OF IMMEDIATE ICING ON THE QUALITY CHARACTERISTICS OF BAGDA (PENAEUS MONODON)

The quality changes in Bagda (Penaeus monodon) stored with ice in bamboo and plastic basket for 24 hours immediately after harvest was observed through visual, biochemical and microbial assessments. As indicator of freshness TVB-N and TMA-N were measured at 0h, 12h, and 24h. The concentration of TVB-N ranged from 5.34±0.0212 to 8.045±0.049 mg/100g in bamboo basket and 4±0.0283 to 7.825±0.0354 mg/100g in plastic basket. TMA-N concentration was found as 2.66±0.0141 to 4.045±0.0071 and 1.345±0.0071 to 5.2±0.0424 mg/100g in bamboo and plastic basket respectively. Data indicated that all the values increased with storage time, quality of shrimp started to decline slowly within 24 hours and remained acceptable in both bamboo and plastic baskets even on 24th hour. Standard Plate Count (SPC) of shrimp stored with ice immediately was 0.18×105 and 0.12×105 in bamboo and plastic baskets, respectively. SPC of shrimp stored with ice after 24 hours was 0.17×105 and 0.23×105 in bamboo and plastic baskets, respectively.

Effect of aerobic and modified atmosphere packaging on quality characteristics of chicken leg meat at refrigerated storage

The demand for chicken meat is continuously increasing in the consumer market. Increasing the shelf-life of chicken meat with modern packaging technology in the supply chain is necessary. Hence research was undertaken to study the effect of aerobic packaging (AP) and modified atmosphere packaging (MAP) on the quality and shelf-life of chicken meat. The chicken leg meat (CLM) was stored under refrigerated storage (4 ± 1°C) in aerobic and modified atmosphere packaging (MAP20 = 20%O2 + 30%CO2 + 50%N2, MAP10 = 10%O2 + 40%CO2 + 50%N2, MAP0 = 0%O2 + 20%CO2 + 80%N2) conditions and evaluated for quality attributes. The results have indicated that MAP of chicken leg meat significantly increased the headspace carbon dioxide, Warner-Bratzler shear force value, standard plate count, color, and odor but decreased the TBARS value, headspace oxygen, and nitrogen when compared with AP. The pH, myoglobin forms, meat pigment, heme iron, CIELAB color space (L*, a*, b*), yeast and mold count, appearance, and sliminess were not affected significantly by AP and MAP. It is concluded that under refrigerated storage conditions, MAP extends the shelf-life of chicken leg meat up to 15 d compared to only 6 d for aerobic packaging.

Mild Positive Pressure Improves the Efficacy of Benzalkonium Chloride against Staphylococcus aureus Biofilm.

Current protocols using liquid disinfectants to disinfect heat-sensitive hospital items frequently fail, as evidenced by the continued isolation of bacteria following decontamination. The contamination is, in part, due to biofilm formation. We hypothesize that mild positive pressure (PP) will disrupt this biofilm structure and improve liquid disinfectant/detergent penetration to biofilm bacteria for improved killing. Staphylococcus aureus biofilm, grown on polycarbonate coupons in the biofilm reactor under shear at 35 °C for 3 days, was treated for 10 min and 60 min with various dilutions of benzalkonium chloride without PP at 1 atmosphere (atm), and with PP at 3, 5, 7, and 10 atm. The effect on biofilm and residual bacterial viability was determined by standard plate counts, confocal laser scanning microscopy, and scanning electron microscopy. Combined use of benzalkonium chloride and PP up to 10 atm significantly increased biofilm killing up to 4.27 logs, as compared to the treatment using disinfectant alone. Microscopy results were consistent with the viability plate count results. PP improved disinfectant efficacy against bacterial biofilm. The use of mild PP is possible in many flow situations or if equipment/contaminated surfaces can be placed in a pressure chamber.