Aerobic Bacterial Plate Counts Research Articles

Evaluation of ATP bioluminescence for rapid determination of cleanliness of livestock trailers after a commercial wash.

Pathogens such as porcine epidemic diarrhea virus (PEDV), porcine reproductive and respiratory syndrome (PRRSV), and E. coli are known to spread by contaminated vehicles and equipment. Pork producers have adopted trailer wash policies where each trailer is washed, disinfected, and dried before it can return to a farm. Cleanliness of livestock trailers after washing is determined by visual inspection rather than any objective method. Adenosine triphosphate (ATP) bioluminescence is used in many industries to provide real-time feedback on surface cleanliness through the detection of ATP from organic sources. That same technology may provide trailer wash facilities a way of objectively characterizing a livestock trailer's suitability to return to a farm after washing. Two ATP luminometers (3M Clean-Trace and Neogen AccuPoint) were used to estimate the correlation between ATP bioluminescence readings and aerobic bacterial plate counts (APCs) from sampled surfaces and to determine locations within a livestock trailer that can accurately estimate surface cleanliness. Five locations in livestock trailers were evaluated. Those locations included the nose access door (NAD), back door flush gate, rear side access door (RSAD), belly flush gate (BFG), and belly side access door (BSAD). There was a positive log-log association between the two luminometers (r = 0.59, P < 0.01). Every log unit increase in one unit, resulted in a 0.42 log increase (P < 0.01) in the other unit. ATP can come from bacteria, yeasts, molds, and manure. There was a poor association (r ≥ 0.10, P ≥ 0.02) between APCs and the ATP luminometers. Still, an increase in relative light units (RLUs) resulted in a corresponding increase in colony-forming units. The greatest area of surface contamination measured by APC was the NAD. RLUs were also greater in the NAD compared to the RSAD, the BFG, and the BSAD (P ≤ 0.01). Because APCs and luminometer RLUs provided similar outcomes, statistical process control charts were developed to determine control limits for RLUs. This provides real-time feedback to trailer wash workers in determining cleanliness outcomes for livestock trailers. These data suggest that ATP bioluminescence can be a reliable method to monitor cleaning effectiveness in livestock trailers. Bioluminescence is a monitoring tool that should be used in conjunction with microbial methods to monitor procedures for cleaning and disinfection.

Quantification, Variability Assessment of Bacterial Pollution and Public Health Hazards Linked to Users of Automated Teller Machines in Ekpoma, Edo State-Nigeria

Raising number of mortals has used automated teller machines (ATMs) over the years, but little is known about their microbial colonization status. Based on this premise, we examined eight out of the nine commercial bank’s ATM in Ekpoma environs for quantification, variability assessment of the bacterial cross contamination and the likely health hazards linked to the users of such cash dispensing machines. A total number of sixteen (16) samples were acquired from eight different commercial banks ATM keypads and screens within the study area, using sterile swab sticks immersed in sterile normal saline. Samples were subsequently transferred to the laboratory section of the Department of Microbiology, Faculty of Life Sciences, Ambrose Alli University, Ekpoma for analyses using standard microbiological procedures for isolation, quantification and identification between the period of September to October 2019. Results showed that the total aerobic bacteria count, Staphylococcus aureus and coliforms counts on both the ATM keypads and Screens ranged from 9.0 × 103±2.65 cfu/m2 to 1.92 × 104±3.61 cfu/m2, 3.5 × 103±1.73 cfu/m2 to 9.8 × 103±4.58 cfu/m2 and 4.8 × 103±1.00 cfu/m2 to 1.08 × 104±2.00 cfu/m2 respectively. One-way Anova depicted a no significant difference (P ˃ 0.05) in the total aerobic bacterial plate count, Escherichia coli and Staphylococcus aureus counts in the various banks’ ATM keypads and screens in respectively of the facilities placement and the number of users. The bacteria implicated in this study were Escherichia coli, Bacillus spp, Klebsiella pnuemoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus spp and Coagulase negative Staphylococcus spp. The findings from this study reveals that high volume of bacterial pollution were detected on ATM hardware user interface which invariably necessitated the need for adequate personal hygiene by both the users and custodians of such machines with a view to reducing the likely hood of spreading contagious agents.

Evaluation of the antioxidant, anti-inflammatory and antimicrobial effects of catuaba, galangal, roseroot, maca root, guarana and polyfloral honey in sausages during storage

The antioxidative, anti-inflammatory and antimicrobial effects of catuaba, galangal, roseroot, maca root, guarana and honey in sausages were investigated during storage at 2 °C for 20 days. Three independent replications of sausages were manufactured to compare groups: the control group (C) and groups where various levels of bioactive components were added (E1, E2, and E3). Each group was examined for chemical composition, total phenolic content (TPC), total antioxidant activity (TAA), anti-inflammatory activity (AA), thiobarbituric acid reactive substances (TBARS), fatty acid profile and total aerobic bacterial plate count (TAPC). Increased levels of TBARS and TAPC values were noticed in all the samples during storage. In the groups where bioactive components were used, improved antioxidant, anti-inflammatory and antimicrobial effects were observed. The best results at the end of storage were obtained for the sausages where the highest dose of the components was used (17.34 g/kg of catuaba bark, 0.22 g/kg of ground great galangal root, 4.58 g/kg of ground roseroot, 6.14 g/kg of maca root extract, 6.00 g/kg of ground guarana and 11.46 g/kg of polyfloral honey). In the examined sausages, strong correlations between TPC and TAA (r2 = 0.82; P < 0.05), TPC and AA (r2 = 0.88; P < 0.05), and TPC and TBARS values (r2 = −0.67; P < 0.05) were obtained.

Identification and Quantification of Microbial Contaminations Present in Herbal Medicines Commonly Consumed by Women in Riyadh, Saudi Arabia

The present study aimed to investigate the microbial populations such a bacteria and fungi contamination present in the herbal medicinal preparations (Lepidium sativum, Nigella sativa, Cuminum cyminum, Foeniculum vulgare, Pimpinella anisum, Trigoneela foenum-graecum, Cinnamomum verum, peel coffee, Alchemilla valgaris, Vitex agnus-castus) commonly available in different parts of Riyadh, Saudi Arabia. To determine the contamination of the herbal products, experiments such as total aerobic bacterial plate counts were evaluated by various plating techniques. The isolation and identification of fungi were done using czapek dox agar and potato dextrose agar. The results showed that a total of herbal remedies were contaminated with bacteria and fungi (100%). Among the contaminated products, peel of coffee and Vitex angnus-castus were noted more contamination than the other herbal medicinal plants. The results confirmed that the traditionally prepared herbal medications in Riyadh city are likely to be contaminated with a wide variety of potentially pathogenic bacteria and fungi. Therefore, before consumption, the quality assurance of these products should be thoroughly enforced and monitored in the production and distribution of herbal preparations. In conclusion, the present study gives proper evidence that the consumed herbal products contain different levels of pathogenic microbes.

Long term impact of waste water irrigation and nutrient rates: I. Performance, sustainability and produce quality of peri urban cropping systems

Farmers in peri-urban areas of developing countries depend on wastewaters for their livelihood but with grave health and environmental risks. An 8-year field experiment compared food grain (FGPS), agroforestry (AFS), fodder (FPS) and vegetable (VPS) production systems and quantified responses to fertilizers (NP 25–100%) when irrigated with sewage (SW; EC 1.3±0.3dSm−1 BOD 82±11, NO3–N 3.2±0.4, NH4–N 9.6±0.5, P 1.8±0.3, K 6.4±0.4mgL−1) vis-à-vis groundwater (GW). Productivity improved with SW by 14–28% while trends were negative with sub-optimal NP under GW. Partial factor productivity (PFP) averaged 18.0, 11.1, 157 and 149kgkg−1 NP with GW in FGPS, AFS, FPS and VPS, respectively. Counter figures were 13.8, 8.8, 96 and 56kgkg−1 NP with SW. Paddy-wheat equivalent yields were 5.5, 1.8 and 19.9 fold under AFS, FPS and VPS with SW. About 40, 33, 75 and 20% of fertilizer NP with SW was sufficient for similar production as with recommended NP and GW in FGPS, AFS, FPS and VPS, respectively. Quality of produce improved in terms of crude protein and the micronutrients in edible parts with SW while toxic metals were within the permissible limits. However, the keeping quality of vegetables was lowered due to faster decay with pathogens contamination (Aerobic bacterial plate counts 5×105–4.2×108cfug−1 and Escherichia coli <2×102–7×105). Thus, the sewage proved as a vital resource in improving productivity, sustainability and saving fertiliser costs but this may pose health risks because of pathogenic infestation that need to be regulated.

Histamine formation and the freshness of yellowfin tuna (Thunnus albacares) stored at different temperatures

AbstractThis study was conducted to investigate the effect of storage temperatures on the shelf life of yellowfin tuna (YFT) loins by studying of microbial, chemical and organoleptic changes. Shelf life of YFT was determined through changes in total aerobic bacterial plate counts (APC), total volatile basic nitrogen (TVB-N) trimethylamine (TMA), organoleptic properties and histamine development during storage at 0, 4 and 7°C. Based on TVB-N value indices, YFT maintained an acceptable shelf life for 21, 17 and 12 days at 0, 4 and 7°C, respectively. Nevertheless, YFT was rejected earlier by the sensory panellists than their TVB-N value indicated. Histamine development was found to be lower than the European Union safety level for 100 mg/kg fish during storage at 0 and 7°C for 21 and 17 days, respectively. Aerobic bacteria initially dominated the micro-flora on YFT; however, as storage time increased, aerobic bacteria became dominant at cold storage, but the numbers exceeded the International Commission on M...

Bacterial Contamination in Saeng-go-gi, a Ready-to-Eat Fresh Raw Beef Dish Sold in Restaurants in South Korea

This study investigated the bacterial contamination levels in ready-to-eat fresh raw beef, Saeng-go-gi in Korean, sold in restaurants. A total of 462 samples were analyzed by performing an aerobic bacterial plate count, a coliform count, and an Escherichia coli O157:H7 count. Aerobic bacterial plate counts of fresh raw beef obtained from Seoul, Cheonan, Daegu, Gunsan, and Gwangju retail store restaurants were 6.46, 6.89, 6.39, 6.58, and 6.67 log CFU/g, respectively, and coliforms were 4.05, 4.97, 4.76, 3.62, and 3.32 log CFU/g, respectively. Among the 462 assessed samples, suspected E. coli O157:H7 colonies were found in 32, 24, 20, 22, and 16 samples obtained from Seoul, Cheonan, Daegu, Gunsan, and Gwangju, respectively. The identity of these isolated colonies was further assessed by using a latex agglutination kit. The agglutination assay data showed that the isolates were not E. coli O157:H7. The data from this study could be used to design better food handling practices for reducing foodborne illnesses linked to fresh raw beef consumption.

Bioaerosol sampling for airborne bacteria in a small animal veterinary teaching hospital

BackgroundAirborne microorganisms within the hospital environment can potentially cause infection in susceptible patients. The objectives of this study were to identify, quantify, and determine the nosocomial potential of common airborne microorganisms present within a small animal teaching hospital.MethodsBioaerosol sampling was done initially in all 11 rooms and, subsequently, weekly samples were taken from selected rooms over a 9-week period. Samples were collected twice (morning and afternoon) at each site on each sampling day. The rooms were divided into two groups: Group 1, in which morning sampling was post-cleaning and afternoon sampling was during activity, and Group 2, in which morning sampling was pre-cleaning and afternoon sampling was post-cleaning. The total aerobic bacterial plate counts per m3 and bacterial identification were done using standard microbiological methods.ResultsA total of 14 bacterial genera were isolated with the most frequent being Micrococcus spp. followed by species of Corynebacterium, Bacillus, and Staphylococcus. There was a significant interaction between location and time for rooms in Group 1 (p=0.0028) but not in Group 2 (p>0.05). Microbial counts for rooms in Group 2 were significantly greater in the mornings than in the afternoon (p=0.0049). The microbial counts were also significantly different between some rooms (p=0.0333).ConclusionThe detection of significantly higher airborne microbial loads in different rooms at different times of the day suggests that the probability of acquiring nosocomial infections is higher at these times and locations.

Food borne pathogen contamination in minimally processed vegetable salads in Riyadh, Saudi Arabia

The increasing demand for fresh fruits and vegetables and for convenience foods is causing an expansion of the market share for minimally processed vegetables in different areas. Riyadh, the capital city of Saudi Arabia witness flourishing of hotel and food industry and eating green salad is a daily habit of about 50% individuals in the country. Hence microbial quality of minimally processed vegetable salads (Tabbouleh, Fattoush, Hummus, Mutabbel and Caesar) being served in restaurants and homes in Riyadh were evaluated to ascertain that they are safe for human consumption and are free from potential food borne pathogens. The samples were assessed for the presence of total aerobic bacterial plate count, total coliforms, Escherichia coli, Salmonella, and Shigella. The total aerobic plate count for salad prepared in the restaurants was around 2 – 4.5 x105 CFU/g, however, in homemade salads the count was 2-8 x 104 CFU/g. The total coliform counts in restaurants salad were around 2-8 x 104 CFU/g as compared to 2-4.8 x 103 CFU/g of homemade salads. All salads, except Caesar, recorded E. coli and Enterobacter aerogenes, whileShigella sp and Salmonella sp were present in few samples. The results of the present study warrant an urgent need to have strict control measures to eliminate food borne pathogen contamination. This is the first report on microbial quality of the said minimally processed vegetable salads in Saudi Arabia. Key words: Saudi Arabia, vegetable salads, fruits, food borne pathogen contamination.

Contamination of herbal medicinal products marketed in Kaduna Metropolis with selected pathogenic bacteria.

The study aimed to evaluate the bacterial contamination of powdered herbal medicinal preparations sourced from identified herbal retail outlets in different parts of Kaduna metropolis. The assessments of the contamination of the herbal products were carried out using standard procedures: total aerobic bacterial plate count, measurement of some physical parameters, isolation and characterization of selected bacterial pathogens etc. The results showed that out of a total of 150, 70 (46.67%) herbal remedies were contaminated with Salmonella typhi, twenty nine (19.33%) with Shigella spp. Eighty eight (58.67%) and 98 (65.33%) were contaminated with Escherichia coli and Staphylococcus aureus, respectively. The total aerobic plate count results showed that the highest average count of > 5x10(7) cfu/g was found in 89 (59.33%) of the preparations, while average plate count of < or = 5x10(7) cfu/g was found in 42 (28%) and no bacterial count was obtained in 19 (12.67%) of the preparations. Correlation was positive (P = 0.01; r = +0.109) between the physical parameters tested and the bacterial load. Antibacterial activities result of some common antibiotics showed that all the antibiotics had activities on the test bacterial isolates at various minimum inhibitory concentrations. Most traditionally prepared herbal medications in Kaduna state are likely to be contaminated with a wide variety of potentially pathogenic bacteria. The quality assurance of these products should be thoroughly enforced and monitored in the production and distribution of herbal preparations.

Aspects of the microbiological quality and safety of ready-to-eat foods in Sharjah supermarkets in the United Arab Emirates.

Over the last few years, ready-to-eat (RTE) foods have become popular in grocery stores all over the world. This study was conducted to evaluate the microbiological safety and shelf life of some RTE salads sold in supermarkets in Sharjah Emirate, United Arab Emirates. Samples of four RTE salads, tabbouleh, hummus, Greek salad, and coleslaw, were obtained from supermarkets and examined for aerobic bacteria, Escherichia coli, Staphylococcus aureus, Salmonella, and Listeria monocytogenes. The results indicated significant differences (P < or = 0.05) for the aerobic bacteria count among the RTE salad types. In tabbouleh, hummus, Greek salad, and coleslaw, E. coli counts of 0.9, 0.50, 0.27, and 0.25 log most probable number (MPN)/g and total aerobic bacterial plate counts of 3.57, 2.71, 2.76, and 2.52 log CFU/g, respectively, were found after preparation (day 0). At day 0, all RTE salads tested except tabbouleh contained an acceptable count of total bacteria, but the aerobic bacteria count for all the RTE salads increased rapidly during storage from day 2 to day 6, regardless of the storage temperature (5, 25, and 40 degrees C). Twenty percent of all samples contained E. coli, although the numbers were as low as 1 log MPN/g. No S. aureus, L. monocytogenes, or Salmonella serotypes were detected in any of the RTE salads tested in this study.

Effect of Different Concentrations of Carbon Dioxide and Oxygen on the Growth of Pathogenic Yersinia enterocolitica 4/O:3 in Ground Pork Packaged under Modified Atmospheres

The influence on Yersinia enterocolitica counts of a gradual increase of carbon dioxide concentrations (percentage by volume in air) during packaging and storage of ground pork meat artificially contaminated with this pathogen was evaluated. Ground meat was packaged under customary conditions using modified atmospheres with various carbon dioxide percentages (0, 30, 50, 70, and 100% CO2 by volume; for atmospheres of less than 100% CO2, the rest of the gas was O2). The packs were stored at 2°C for 12 days. During the entire storage time, counts of Y. enterocolitica were determined by the spread plate method for direct plate counts (DPCs). Microbiological shelf life of the stored ground pork also was assessed by total mesophilic aerobic bacterial plate counts (APCs). Y. enterocolitica counts were not significantly different (P ≥ 0.05) in the ground pork packaged under the various CO2-enriched atmospheres. The growth of Y. enterocolitica was nearly entirely inhibited in all tested modified atmospheres containing the protective CO2. However, in ground pork packaged with 100% oxygen, there was a significant decrease (P ≤ 0.05) in the DPC for Y. enterocolitica from 4.30 log CFU/g (day 0) to 3.09 log CFU/g at the end of the storage time (day 12). The decrease was presumably due to the marked increase in APC seen only in those packages stored under 100% O2. Packaging with high CO2 concentrations had significant inhibitory effect (P ≤ 0.05) on the growth of mesophilic aerobic bacteria.

Inhibition of Listeria innocua in Hummus by a Combination of Nisin and Citric Acid

The effect of nisin or citric acid or combinations of these two inhibitors on the inactivation of a cocktail of three Listeria innocua strains was investigated in a model brain heart infusion (BHI) broth and hummus (chickpea dip). In BHI broth, citric acid had a limited ability to inhibit L. innocua growth. Nisin initially reduced L. innocua concentrations by about 3 log cycles; however, L. innocua reached concentrations similar to those of the control after 5 days at 22°C. In combination, the effects of 500 IU/ml nisin and 0.2% citric acid were synergistic and resulted in complete elimination of L. innocua in the BHI broth. The inhibition of L. innocua by nisin (500 or 1,000 IU/g), citric acid (0.1, 0.2, or 0.3%), or their combinations also was evaluated in hummus. Citric acid alone did not affect L. innocua growth or the aerobic bacterial plate count. A combination of 1,000 IU/g nisin and 0.3% citric acid was somewhat effective (∼1.5-log reduction) in controlling the concentration of L. innocua and the aerobic plate count for up to 6 days. This combination also may be useful, in addition to proper hygienic practices, for minimizing the growth of the pathogen Listeria monocytogenes in hummus.

Prevalence and control of pathogenic contamination in some sewage irrigated vegetable, forage and cereal grain crops

A total of 344 samples comprising of different vegetables, fodder and grain crops were obtained from a long-term experiment under sewage irrigation. The aerobic bacterial plate counts for vegetables, fodder and grain crops ranged between 2 × 10 6 and 3.5 × 10 7, 6 × 10 6 and 3 × 10 8, 2 × 10 5 and 3.8 × 10 10, respectively, while the corresponding Faecal coliform ranged between <2 and 9 × 10 5, 9 × 10 2 and 2 × 10 5 and <2, indicating that the pathogenic loads got reduced below permissible level in the produce that was harvested after sun drying in the field itself, whereas the parts coming in direct contact were the most severely contaminated. The health hazards could be markedly lowered with adoption of some of the low cost practices such as repeated washings, exposure of the produce to sunlight and raising the crops on beds. The coliform counts in vegetables were within permissible limits by two washings with water, exposing these to sunlight for about 4 h and removing the two outmost leaves of cabbage. Also, cutting above some height from ground level (0.10 m) in sorghum reduced the pollution load in fodder crops.

Influence of Fruit Variety, Harvest Technique, Quality Sorting, and Storage on the Native Microflora of Unpasteurized Apple Cider

Apple variety, harvest, quality sorting, and storage practices were assessed to determine their impact on the microflora of unpasteurized cider. Seven apple varieties were harvested from the tree or the ground. The apples were used fresh or were stored at 0 to 4°C for ≤5 months and were pressed with or without quality selection. Cider yield, pH, Brix value, and titratable acidity were measured. Apples, postpressing apple pomace, and cider samples were analyzed for aerobic bacteria, yeasts, and molds. Aerobic bacterial plate counts (APCs) of ciders from fresh ground-picked apples (4.89 log CFU/ml) were higher than those of ciders made from fresh, tree-picked apples (3.45 log CFU/ml). Quality sorting further reduced the average APC to 2.88 log CFU/ml. Differences among all three treatment groups were significant (P < 0.0001). Apple and pomace microbial concentrations revealed harvest and postharvest treatment-dependent differences similar to those found in cider. There were significant differences in APC among apple varieties (P = 0.0001). Lower counts were associated with varieties exhibiting higher Brix values and higher titratable acidity. Differences in APC for stored and fresh apples used for cider production were not significant (P > 0.05). Yeast and mold counts revealed relationships similar to those for APCs. The relationship between initial microbial load found on incoming fruit and final cider microbial population was curvilinear, with the weakest correlations for the lowest apple microflora concentrations. The lack of linearity suggests that processing equipment contributed to cider contamination. Tree-picked quality fruit should be used for unpasteurized cider production, and careful manufacturing practices at cider plants can impact both safety and quality of the final product.

Microbial Counts of Selected Hot-Boned Primals and Ground Beef

Twenty-four dairy cows were slaughtered under commercial conditions, muscles were excised from one side within 3 h of slaughter and from the second side after 24 h chill at 3°C. Surface aerobic bacterial plate counts, (APC5, 20, and 35°C, that is, plates were incubated at 5, 20 and 35°C, respectively) obtained from the rounds immediately before deboning did not vary significantly between the hot and chilled carcasses. The APC (5, 20, and 35°C) increased (P<.01) during removal of rounds from both hot and chilled carcasses, and the magnitude of the increase was greater than one logarithm. The bacterial count on loins and rounds that were overwrapped and frozen generally was lower than on loins and rounds held at 3°C for 7 and 14 d before being frozen. The APC (5, 20, and 35°C) of fresh ground beef fabricated in 450-kg batches from trimmings of hot cow carcasses were not significantly different from that made from the chilled carcasses. Addition of chilled USDA Choice plates to increase the fat content and lower the temperature of the manufactured ground beef increased (P<.01) APC counts in most instances. The log count of the USDA Choice plates was about 5 to 6/cm2; whereas that of the cow beef was about 2 to 4/cm2. The mean counts of coliforms, fecal coliforms and Escherichia coli were usually less than one log, so significant treatment differences, when they did occur, were unimportant. Results of this research indicate that hot boning does not adversely affect the microbial quality of selected primals and ground beef.