Total Number Of Viable Bacteria Research Articles

Effect of the Addition of Dandelion (Taraxacum officinale) on the Protein Profile, Antiradical Activity, and Microbiological Status of Raw-Ripening Pork Sausage.

The study evaluated the effect of adding dandelion extract on the characteristics of raw-ripening pork sausages while reducing the nitrite addition from 150 to 80 mg/kg. The sausages were made primarily from pork ham (80%) and pork jowl (20%). The process involved curing, preparing the meat stuffing, forming the links, and then subjecting the sausages to a 21-day ripening period. Physicochemical parameters such as pH, water activity, and oxidation-reduction potential were compared at the beginning of production and after the ripening process. The study also examined the impact of ripening on protein metabolism in pork sausages and compared the protein profiles of different sausage variants. The obtained research results indicate that dandelion-leaf extract (Taraxacum officinale) were rich in phenolic acids, flavonoids, coumarins, and their derivatives (LC-QTOF-MS method). Antiradical activity test against the ABTS+* and DPPH radical, and the TBARS index, demonstrated that addition of dandelion (0.5-1%) significantly improved the oxidative stability of raw-ripening sausages with nitrite content reduction to 80 mg/kg. A microbiological evaluation of the sausages was also carried out to assess the correctness of the ripening process. The total number of viable bacteria, lactic acid bacteria, and coliforms were evaluated and subsequently identified by mass spectrometry.

Study and microbial evaluation of homemade meat meals sold in the markets of the city of Al Bayda – Libya

Background: Home-cooked meals were frequently linked to foodborne diseases. Microbial contamination of meals depends on many factors: handling and preparing of foods, the environment and quality of raw materials, and also habits of cooks. People who sell such meals for customers with lower income in the street are at risk from foodborne diseases and a need for periodical control to protect them. Deleterious microorganisms present in food may produce toxins and other harmful substances; some may spoil foods and cause off-odors and off-flavors. Objective: the aim of this study is to evaluate microbial contamination in home-made meat and meals sold in the markets of the city of Al-Bayda – Libya Methods: This study evaluated 40 samples of home-prepared meat in the city of Al-Bayda(20 red meat meals and 20 poultry meat samples). All samples were tested for the total number of viable bacteria, E. coli, Staphylococcus aureus, Enterococcus, psychoactive and Anaerobic bacteria, mold count, and yeast count Results: The study showed that the average number of home meals red meat and processed poultry were 14.63 x 106, 19.19 x 105,10.35 x 510, 16.04 x 105, 104 x 3.8, and 7.39 x 105 CFU/g, respectively. The percentage of Staphylococcus aureus is 46.4% and 40% in processed red meat and poultry meals, respectively. Conclusion: The research showed that aerobic Bacteria did not grow in all the meals that were tested, and these results demonstrated the importance of this, which gave a serious indication that all home-prepared meat is dangerous to human health.

Effect of ‘Peatland-Use’ Type on Culturable Microbial Groups in Irish Peatlands in the Midlands

Soil microbial ecology in the Irish wetlands is still poorly understood, although it is crucial in introducing effective rewetting schemes to restore and conserve the Irish peatlands. As an initiative, peatlands with distinct land-use types (cutaway, raised semi-degraded, unimproved grassland and grassland) were collected from farms in the midlands to analyse various microbial populations. Peat was homogenized and serially diluted to culture on a range of specific and non-specific culture media. Culture isolation and microbial enumeration were performed. Gram staining and other microscopic observations of morphologically distinct microorganisms were performed, followed by isolation procedures. The numbers of total viable bacteria of cutaway bog and unimproved grassland were 4.23 × 103 CFU g−1 and 9.81 × 107 CFU g−1, respectively, with a significant statistical difference (p ≤ 0.05). Raised semi-degraded bogs comprised low values of both aerobes and fungal populations. Penicillium spp. and Trichoderma spp. were common in many vegetation types. Phosphate-solubilizing bacteria were present in the majority of the study sites. This indicated that the soluble form of phosphorus was being assimilated by plants. Cutaway peat contained the bacteria with the highest phosphate-solubilizing index (3.167). Overall, the number of culturable microbial groups in cutaway and raised semi-degraded peatlands exhibited significant differences, while the rest did not show drastic changes according to land-use type. This study provides baseline data to continue studies on bog microbiology, which provides a new outlook for restoration. Future work should consider microbial interaction with environmental variables in different land-use types.

Effects of cold storage time on the quality and active probiotics of yogurt fermented by Bifidobacterium lactis and commercial bacteria Danisco.

In this study, the commercial bacteria Danisco and Bifidobacterium lactis were used to ferment soy yogurt, and then the quality of yogurt and the number of active probiotics in yogurt during storage were investigated. The results showed that the total number of viable bacteria in soy yogurt increased first and then decreased, but all of them met the standard for the number of viable bacteria in probiotic foods. The content of protein, lipid, and total sugar in soy yogurt decreased gradually with the extension of storage time. The texture, water holding capacity, and rheological properties of soy yogurt were improved within 0-10 days, and there was no significant change after 15 days. However, brightness and whiteness of yogurt were significantly reduced. Based on realizing the reuse of soy whey, this study provided a theoretical basis for the research of the shelf life of soy yogurt. PRACTICAL APPLICATION: This study developed a soy yogurt with good quality and provided a theoretical basis for the study of the shelf life of soy yogurt. In addition, some technical support was provided for the reuse of soy whey.

Effects of high hydrostatic pressure on inactivation, morphological damage, and enzyme activity of Escherichia coli O157:H7

AbstractHigh hydrostatic pressure (HHP) is a nonthermal processing technology that can maintain the original color, flavor and nutritional components of food during preservation. In this study, the mechanism of HHP to inactivate Escherichia coli O157:H7 was studied and clarified. Along with the increase of treatment pressure, the total number of viable bacteria decreased significantly (p < 0.05). Different HHP treatments destroyed the integrity of E. coli O157:H7 cell membrane and had a certain effect on the content and activity of the whole protein profiles. Scanning electron microscopy and transmission electron microscopy confirmed that HHP caused membrane damage of E. coli O157:H7. In addition, the effects of HHP on enzyme activity, glucose metabolism and iodonitrotetrazolium chloride metabolic reduction activity showed that HHP could interfere with glycolysis and tricarboxylic acid cycle pathway of E. coli O157:H7. In general, HHP has multiple targets for the inactivation mechanism of E. coli O157:H7.

Effect of bioactive glass air-abrasion on Fusobacterium nucleatum and Porphyromonas gingivalis biofilm formed on moderately rough titanium surface.

This aim of this study was to investigate the effects of three types of air-abrasion particles on dual-species biofilms of Fusobacterium nucleatum and Porphyromonas gingivalis, both of which were cultured on sandblasted and acid-etched (SA) titanium discs. Out of 24 SA discs with biofilm, 18 were exposed to either air-abrasion using Bioglass 45S5 (45S5 BG; n=6), novel zinc (Zn)-containing bioactive glass (Zn4 BG; n=6), or inert glass (n=6). The efficiency of biofilm removal was evaluated using scanning electron microscopy (SEM) imaging and culturing techniques. Air-abrasion using 45S5 BG or Zn4 BG demonstrated a significant decrease in the total number of viable bacteria compared to discs air-abraded with inert glass or intact biofilm without abrasion. Moreover, P.gingivalis could not be detected from SEM images nor culture plates after air-abrasion with 45S5 BG or Zn4 BG. The present study showed that air-abrasion with 45S5 or Zn4 bioactive glasses can successfully eradicate dual-biofilm of F.nucleatum and P.gingivalis from sandblasted and acid-etched titanium discs.

The occurrence of drug-resistant bacteria and screening the possible presence of residual antibiotics in poultry feed samples

The use of antibiotics in the poultry and livestock industries for the treatment and prevention of infectious diseases, and as growth promoters in poultry feeds has increased worldwide. Such frequent employment of antibiotics may contribute to the development and dissemination of bacterial antibiotic resistance. The present study was an attempt to isolate drug-resistant bacteria and to screen the probability of having residual antibiotics in the poultry feed samples. Therefore, a total of 18 samples inclusive of starter, grower and finisher of two poultry feed brands of reputed Bangladeshi feed companies were collected and subjected to microbiological analysis, antibiogram and agar well diffusion assay. All the samples contained extended numbers of total viable bacteria and fungi in an average of 108 and 107 cfu/g, respectively. Klebsiellaspp., Pseudomonas spp. and Bacillus spp. were predominantly present in the tested samples. E. coli and Vibrio spp. were also found in most of the samples. Most isolates have been determined to be multidrug-resistant. All the isolates showed resistance against Cefuroxime. Penicillin resistance was found in most of the isolates in greater proportion. Higher rate of resistance was evident against Novobiocin, Cephradine and Rifampicin. However, the bacterial isolates showed sensitivity to Tobramycin, Nalidixic acid and Neomycin. The poultry feed samples, especially starter and finisher of both brands noticeably had significant antimicrobial activity against the laboratory isolates indicative of the probable presence of residual antibiotics which might be used as supplements in the poultry feed samples.
 Stamford Journal of Microbiology, Vol.10 (1) 2020: 30-34

Detection and distribution of vbnc/viable pathogenic bacteria in full-scale drinking water treatment plants

Viable but non-culturable (VBNC) bacteria have attracted widespread attention since they are inherently undetected by traditional culture-dependent methods. Importantly, VBNC bacteria could resuscitate under favorable conditions leading to significant public health concerns. Although the total number of viable bacteria has been theorized to be far greater than those that can be cultured, there have been no reports quantifying VBNC pathogenic bacteria in full-scale drinking water treatment plants (DWTPs). In this work, we used both culture-dependent and quantitative PCR combination with propidium monoazide (PMA) dye approaches to characterize cellular viability. Further, we established a method to quantify viable pathogens by relating specific gene copies to viable cell numbers. Ratios of culturable bacteria to viable 16S rRNA gene copies in water and biological activated carbon (BAC) biofilms were 0–4.75% and 0.04–56.24%, respectively. The VBNC E. coli, E. faecalis, P. aeruginosa, Salmonella sp., and Shigella sp. were detected at levels of 0–103 cells/100 mL in source water, 0–102 cells/100 mL in chlorinated water, and 0–103 cells/g in BAC biofilms. In addition, differences between the total and viable community structures after ozonation and chlorination were investigated. The relative abundance of opportunistic pathogens such as Mycobacterium, Sphingomonas, etc. increased in final water, likely due to their chlorine resistance. In summary, we detected significant quantities of viable/VBNC opportunistic pathogens in full-scale DWTPs, confirming that traditional, culture-dependent methods are inadequate for detecting VBNC bacteria. These findings suggest a need to develop and implement rapid, accurate methods for the detection of VBNC pathogenic bacteria in DWTPs to ensure the safety of drinking water.

Comparative analysis of microbiota of oral fluid in patients with psychoneurological disorders using toothpaste with the enzyme «bromelain»

Relevance. The complex of actions for decrease in growth of diseases of the maxillofacial region includes the reorganization of the mouth, creating an individual program for hygiene and prevention. Among the large number of types of therapeutic and preventive hygiene products for patients with neuropsychiatric disorders, given the burdened somatic status, the program should include safe for use basic and additional means.Purpose. Comparative assessment of oral fluid microorganisms in patients with psychoneurotic disorders before and after 6 months of using toothpastes with the enzyme «bromelain».Materials and methods. A comparative analysis of the oral fluid microflora in patients with high intensity and activity of the cariosity, with positive (psychoneurological disorders) anamnesis and without comorbidities has been carried out. The mouths of all studied patients were sanitized, and a program of personal oral hygiene using hygienic toothpastes and with the enzyme «bromelain» was developed.Results. The conducted research does not prove the bactericidal effect of the enzyme «bromelain» on oral microflora, however, a significant decrease of the total number of viable bacteria, changes in the species composition, and the degree of hemolecular properties indicates an indirect bacteriostatic effect of this enzyme in the composition of the toothpastes, which can be considered as a positive effect on the decrease of caries activity in patients with «negative» dental status (caries intensity index > 9, hygiene index by the method of Yu.A. Fedorov and V.V. Volodkina > 2 points, 3rd degree of caries activity by T.F. Vinogradova), including in patients with psychoneurological disorders.Conclusion. The use of enzyme «bromelain» in toothpastes in patients with neuropsychiatric disorders contributes not only to the safe and intensive cleavage of soft plaque, but also to a positive effect on the microbiota of the oral fluid, which is a favorable prognostic criterion for reducing the activity of the carious process.

Microbiological profiling of food additives and evaluation of their antibacterial efficacy

Food additives are widely used to enhance the taste, texture, appearance and longevity of food items. The aim of this study is to determine the quality and antibacterial activity of different food additives and preservatives. In this study 8 categories of food additives were collected from different super shops in Dhaka city. Almost 90% samples were free from pathogenic microorganisms and a low number of total viable bacteria were found in all samples. Antibacterial activities of these samples were measured by agar diffusion method. Except food color, all remaining categories exhibited zone of inhibition against tested laboratory isolates between 8 mm and 22 mm in diameter. These findings indicate that adding food additives or preservatives in food item can reduce or prevent the growth of pathogenic microorganisms. Harmful effects of food additives to human health need to be evaluated before they are applied in food items.
 Stamford Journal of Microbiology, Vol.9(1) 2019: 23-26

Galactooligosaccharide effects as prebiotic on intestinal microbiota of different fish species

Manipulation of the gut microbiota toward potentially beneficial bacteria (probiotics) has beneficial effects on fish physiology and health. The effects of prebiotics on gut microbiota are species specific. The present study aimed at investigation of the effects of galactooligosaccharide (GOS) as prebiotic on intestinal microbiota of Caspian roach and Caspian white fish fingerlings. which are among the most economically valuable species in the Caspian Sea. The study was conducted in a completely randomized design with two set of experiment each of them include three treatments in triplicates in which 0 (control), 1 and 2% GOS were used in diet for 6 weeks. At the end of the period, changes in the intestinal microbiota, including total bacterial count, lactic acid count and lactic acid bacteria (LAB) levels and dominance of LAB in the intestinal microbiota, were measured by culture-based method. Dietary GOS had no significant effect on total bacterial count in both species (P < 0.05). The LAB levels in the intestinal microbiota in the treatments fed with prebiotics was significantly higher than the control group (P < 0.05). LAB bacteria showed the highest increase and dominance in treatments fed with 2% GOS. Also, the highest ratio of lactic acid bacteria to the total number of viable bacteria was observed in the treatment with 2% GOS treatment (P < 0.05). The results of this study indicated the possibility of alterations in the bacterial communities of Caspian roach and Caspian white fish fingerlings gut toward beneficial bacterial communities using GOS as prebiotic.

Effect of chemical preservatives on the shelf life of tomato juice

Abstract This research conducted with the fully fresh, ripe and sound tomato (Lycopersicon esculentum Mill.) was collected then washed, peeled, seeds removed and transferred to the juice extractor. Sugar, preservatives were added to the extracted filtrated juice. Then the juice was heated, cooled and bottled for preservation. Tomato juice was prepared with three different treatments. Among the three treatments T1, T2 and T3 sample were prepared with no preservative, Na-benzoate preservative and potassium meta-bisulphite (KMS) preservative respectively. The organoleptic observation of this tomato juice was studied for 60 days storage period. Chemical analysis and sensory tests were carried out during the 30 days at an interval of 15 days to assess the effect of chemical additives on the shelf life of tomato juice. Negligible Change in chemical constituents except vitamin C was observed in the prepared juice throughout the 30 days storage period. Color was gradually faded and slightly off flavor develops at the end of the storage periods. The treatment T2 secured highest score for color, flavor, taste and overall acceptability and ranked as “Like very much” by a taste testing panel. Tomato juice prepared with no preservative (T1) spoiled after 45 days storage and juice prepared with KMS preservative (T3) spoiled after 60 days storage. Total number of viable bacteria was highest in tomato juice treated with no preservative (T1) and KMS preservative (T3). Tomato juice with Na-benzoate preservative (T2) contained least viable bacteria which was better than T1 and T3 sample. Considering all the parameters, Na-benzoate tends to be better additives than potassium meta-bisulphite (KMS) for preservation of tomato juice.

Antibacterial and Cytotoxic Potential of a Brazilian Red Propolis

Objective: To evaluate in vitro the effect of a red propolis ethanolic extract (RPE) in the prevention of growth of a cariogenic biofilm and its cytotoxic potential. Material and Methods: Minimum inhibitory and bactericidal concentrations (MIC and MBC) of RPE against Streptococcus mutans and Lactobacillus casei were determined. The cytotoxic potential of 0.4% RPE in oral fibroblasts was observed after 1, 3 and 5 min of contact. Cellulose membrane disks (13 mm, N=12) were used for biofilm formation (24 h) of S. mutans and L. casei , which were treated (1 min) with 0.4% RPE or 0.12% Chlorhexidine (CHX). The control group of biofilm formation was not submitted to any treatment. Serial dilutions were then made to evaluate microbial viability. Descriptive data analysis and, for microbial viability, Mann Whitney test were performed (p≤0.05). Results: RPE showed similar MIC and MBC (4.46 mg/mL) against S. mutans and, for L. casei , they were 8.92 mg/mL (MIC) and 17.85 mg/mL (MBC). CHX presented MIC and MBC 0.05). Regarding the total number of viable bacteria (Log 10 CFU/mL), the RPE (6.55) and CHX (6.87) presented similar efficacy (p>0.05). Conclusion: Red propolis extract showed antibacterial activity against the tested strains, exhibited acceptable cytotoxicity and reduced the colonization of S. mutans and L. casei in a biofilm membrane model.

Microbiological analysis and determination of antibacterial activity of apple samples collected from local markets in Dhaka city, Bangladesh

Present study attempted to detect the prevalence of contaminating microorganisms in 10 categories of local market apple samples commonly consumed in Dhaka city, Bangladesh. A significant number of total viable bacteria were quantified up to 106 cfu/g in these samples. Staphylococcus spp. was the predominant isolate within a range of 1.0×104– 3.2×106cfu/g whereas Escherichia coli, Klebsiella spp., Salmonella spp., Shigella spp., Pseudomonas spp. and Vibrio spp. were also quantified. Fungal contamination (within the range of 105 cfu/g – 107cfu/g) was also observed. Alarmingly most of the bacterial isolates present in the samples were proved to be multi-drug resistant. Antibacterial activity of the samples was tested against some common bacterial isolates but was found to be ineffective.Stamford Journal of Microbiology, Vol.6(1) 2016: 11-15

전통누룩을 이용한 ale맥주 제조 및 품질특성

Nuruk, a traditional Korean alcoholic beverage starter, was evaluated as an additional saccharifying agent comprising up to 1.5% (w/w) of malt weight in ale-type beer processing. Sample characteristics were monitored during fermentation, ripening, and storage. Beer containing nuruk showed higher numbers of total viable bacteria and yeast cell counts. Additionally, ethanol (6.19-6.35%), color (Standard Reference Method), foam stability (228.49-368.24 Σ), saccharogenic power (307-417), and reducing sugar (3.83-5.25%) increased as the amount of nuruk was increased, while viscosity (3.13-2.07 cP) and bitterness unit (19.68-13.13) were lower than in samples without nuruk. Overall acceptance and aftertaste of the beer were significantly higher in a preference test. These results demonstrate that nuruk can be used to produce a new type of ale.

Bacterial communities of fresh goat meat packaged in modified atmosphere

The objective of this work was to study the growth and development of fortuitous flora and food pathogens in fresh goat meat packaged under modified atmospheres containing two different concentrations of CO2. Meat samples were stored at 10 °C under two different modified-atmosphere packing (MAP) conditions: treatment A had 45% CO2 + 20% O2 + 35% N2 and treatment B had 20% CO2 + 55% O2 + 25% N2. During 14 days of storage, counts of each bacterial group and dominant species identification by 16S rRNA gene sequencing were performed to determine the microbial diversity present. The MAP condition used for treatment A was a more effective gas mixture for increasing the shelf life of fresh goat meat, significantly reducing the total number of viable bacteria and enterobacteria counts. Members of the Enterobacteriaceae family were the most common contaminants, although Hafnia alvei was dominant in treatment A and Serratia proteamaculans in treatment B. Identification studies at the species level showed that different microorganisms develop under different storage conditions, reflecting the importance of gas composition in the modified atmosphere on the bacterial community. This work provides new insights into the microbial changes of goat meat storage under different MAP conditions, which will be beneficial for the meat industry.

Effect of pretreatments and packaging on the growth of bacteria in value added summer onion products

The experiment was carried out to investigate the bacteria in fresh and different processed onion. Total number of viable bacteria (cfu/g) in fresh onion and dehydrated processed onion packed in High Density Ployethylene (HDPE) and Aluminum foil (ALF) was estimated at 0, 6 and 12 month interval following storage at room temperature (RT, 20-250C) and refrigerated temperature (RFT, 50C). Samples tested were fresh onion (S0), dried onion (S1), blanched and dried (S2), blanched + sulphited and dried (S3), 25% salt osmosed and dried (S4), 60% sugar osmosed and dried (S5) and 55/15% sugar-salt osmosed dried onion (S6). It was found that the lowest bacterial count (2X101 and 9X101 cfu/g) was given by 25% salt osmosed onion (S4) and the total number of vialed bacteria (TVB) count in the other samples varied in the order of S3‹ S6 ‹ S5‹ S2 ‹ S1 (45-97x103 cfu/g) and sample S1 having no pretreatment before drying gave the highest TVB among the samples and the preservation effect was only due to reduction of aw during drying.Bangladesh J. Agril. Res. 41(3): 507-519, September 2016

Optimization of high- density fermentation conditions for Lactobacillus plantarum by response surface methodology

In this study,response surface methodology was applied to optimize high density fermentation parameters for Lactobacillus plantarum KLDS 1.0391.Central composite design was used to optimize fermentation temperature,fermentation p H and inoculation following the single factor tests. Corn steep powder was used as fermentation medium and the total number of viable bacteria was used as the main indicator. The results showed that the influence of three factors on the number of viable bacteria in the fermentation broth was in order as follows: fermentation temperature > inoculation > fermentation p H. The number of viable bacteria achieved9.58 lg CFU / m L under the optimum fermentation parameter which included fermentation temperature of 34.7 ℃,fermentation p H of 6.2,inoculation of 3.1% and fermentation time of 11 h.There's no significant difference between the results obtained according to optimum conditions and the predicted value,and the relative error was 1.33%between them.The established model can effectively reflect the actual fermentation conditions.

Effect of carboxymethyl cellulose-based coatings incorporated with Zataria multiflora Boiss. essential oil and grape seed extract on the shelf life of rainbow trout fillets

To prolong the shelf life of seafood products, lipid oxidation and growth of microorganisms should be retarded. The objective of the current study was evaluating the potential application of carboxymethyl cellulose (CMC) coatings incorporated with Zataria multiflora Boiss. essential oil (ZMEO) and grape seed extract (GSE) on chemical (thiobarbituric acid reactive substances (TBARS) and total volatile basic nitrogen (TVB-N)), microbial (total viable count, lactic acid bacteria and Pseudomonas spp.) and organoleptic attributes of rainbow trout fillets during refrigerated storage for twenty days. GC–MS analysis showed that ZMEO is rich in monoterpene phenols such as thymol and carvacrol. The following results were obtained after 20 days of storage: The minimum level of TVB-N was measured in the fillets coated with CMC + 2% v/v ZMEO + 0.5% v/v GSE. The minimum number of total viable bacteria, lactic acid bacteria and Pseudomonas spp. were determined in the fillets coated with CMC + 2% v/v ZMEO + 1% v/v GSE. The fillets coated with CMC + 1% v/v ZMEO + 1% v/v GSE showed the best organoleptic properties. Our results revealed that CMC-based coatings incorporated with ZMEO and GSE could improve chemical, microbial and sensorial characteristics of rainbow trout fillets during cold storage.

Investigation of microbiological spoilage and demonstration of the anti-bacterial activity of the major imported fruits within Dhaka Metropolis

With a previous observation of the in vitro anti-bacterial traits posed by both local and imported fruit alcoholic extracts, present study further endeavored principally to chalk out such properties of the imported fruit blends without alcoholic extraction. Experiments regarding microbiological load demonstrated the prevalence of huge number of total viable bacteria (~107 cfu/g) as was also observed in the earlier research while the fungal load was nominal. Among the pathogenic bacteria, Pseudomonas spp. was found to be more prevalent, closely followed by staphylococcal proliferation. The study of anti-bacterial activity revealed that guava, apple and malta samples possessed strong anti-bacterial traits while the dragon fruit samples exhibited least activity and the orange samples were found with moderate anti-bacterial activity. On the basis of our earlier results, the findings of the current study thus put forward a comparison among the alcoholic extracts and the crude fruit blends. DOI: http://dx.doi.org/10.3329/sjm.v4i1.22752 Stamford Journal of Microbiology, Vol.4(1) 2014: 1-4