Bacteria and fungi co-biodeterioration of selected fresh tomatoes sold within Ungwan Rimi, Kaduna

This study investigate the bacteria and fungi associated with the deterioration of fresh tomatoes, (Lycopersicum esculentum). A total of sixteen (16) tomato samples where obtained from four (4) different retail outlets in Ungwan Rimi area, Kaduna. The Proximate composition of the selected tomato samples were determined using standard protocol. Pour plate method was used to isolate bacteria and fungi from the tomato samples. The antibiogram of selected antibiotics and antifungal drugs against the bacteria and fungi isolates were determined using disk diffusion technique. The results of proximate composition showed that sample A had moisture content of 94.10 %, 0.74% of ash, 0.97 % of crude protein, 0.66 % of crude fat, 1.10 % crude fiber and 2.43 % of carbohydrate while sample B showed similar percentage composition of 93.89 % of moisture content, 0.86 % of ash, 1.0 % of crude protein, 0.69 % of crude fat, 1.34% of crude fibre and 2.22 % of carbohydrate. Bacteria isolated and identified were Staphylococcus aureus, Escherichia coli, and Salmonella sp. The most prevalent bacteria isolate was Staphylococcus aureus with 50% while Salmonella sp and Escherichia coli had 25% each. The fungal isolates were Penicillium sp, Aspergillus niger and Aspergillus flavus. Aspergillus niger was the most prevalent with 53.8% , Penicillium sp had 30.8%, while Aspergillus flavus had the least prevalence of 15.4%. the antibacterial susceptibility of Salmonella sp showed that it was resistant to Gentamycin, moderately sensitivity to Streptomycin and Septrin, and sensitive to Choramphenicol, Spafloxacin, Ciprofloxacin, Amoxycillin, Pefloxacin, Tarvid and Augmentine at different concentrations respectively. At different concentrations of the antibiotics, Escherichia coli was resistant to Gentamycin and Streptomycin, sensitive to Choramphenicol, Spafloxacin, Ciprofloxacin, Amoxycillin, Pefloxacin, Tarvid and Augmentine. Staphylococcus aureus was resistant to Rocephin, Zinacef and Streptomycin, moderately sensitive to Ampiclox, and Amoxicillin, and sensitive to Septrin, ciprofloxacin, Gentamycin, Pefloxacin, and erythromycin respectively. The antifungal susceptibility showed variations at different concentrations in it effect against the test fungi isolates.The presence of these fungi, as well as the bacteria isolates, which are capable of causing food poisoning, raises concern over public health risks that may be associated with the consumption of spoilt fresh tomato. Proper handling, transportation and thorough washing with clean or chlorinated water will reduce the risk of tomato spoilage associated with bacteria and fungi species

Bacterial contamination of operating theatres: a case study of a hospital in Northern Nigeria

Microbial contamination of the Operating Theatre (OT) has continued to increase the prevalence of nosocomial infections. This study assessed the level of microbial contamination and the antimicrobial pattern of the bacterial isolates. Swab plate method was used to collect samples from surfaces and other articles in the major OT. Collected samples were transported and microbiologically processed using standard procedures. Three hundred and fifty (350) swab specimens were collected from various inanimate objects and surfaces in the operating theatre. Of the three hundred and fifty specimens collected, two hundred and five (205=58.6 %) swab specimens had bacterial growth. The total of 393 bacterial pathogens were recovered from all specimens processed during the study. Among these, 245(62.3 %) were Gram-positive and 148(37.7 %) were Gram-negative bacteria. The bacteria isolates were, Staphylococcus aureus 50(57.5 %), Coagulase negative Staphylococci 19(21.8 %), Bacillus species 9(10.3 %), Enterobacter species 6(3.8 %), Micrococcus species 6(6.9 %), Streptococcus species 3(4.4 %). Proteus species 128(86.5 %), E. coli 13(8.8 %), and Salmonella species 7(4.7 %). Antibiotic susceptibility pattern of bacterial pathogens showed overall sensitivity of 95 % to Rocephin. 3(100 %). Erythromycin and Gentamycin were resistant to the tested organisms. In general, the results indicate that Staphylococcus aureus, coagulase-negative Staphylococci and Proteus species were the major species contaminating the surfaces in the operating rooms. This may be due to Staphylococci been of human origin. Microbiological surveillance of operating theatres can play an important role in reducing bacterial contamination consequently preoperative infectious episodes can be reduced considerably

Conventional and molecular characterization of selected Lactic acid bacteria from fermented corn gruel (ogi) and fermented milk (nono)

Fermented foods have served as important vehicle for microbial flora that have overtime formed a niche as part of the human diet. One of such is the Lactic acid bacteria which are nonpathogenic, extensively disseminated and keenly included in most fermentative procedures. This research was conducted to isolate lactic acid bacteria from fermented food sources. Pour plate method was used for the isolation of bacteria on MRS media. The bacteria isolates obtained from fermented corn gruel (ogi) and fermented milk (nono) were characterized through conventional and molecular methods. A total of six (6) bacteria isolates were recovered and identified to reveal a community of bacteria dominated by Lactobacilli sp and Bacillus sp. Specie identification was based on sequence analysis of 16SrRNA gene resulting in 4 Lactobacilli sp made up of 1 L. plantarum, 2 L acidophilus, 1 L. fabifermentan and 1 Bacillus sp. However, one of the isolates was identified as coccobacilli due to its peculiar structure on the basis of its microscopy and biochemical reaction only. The mean total aerobic bacteria plate count ranged from 2.0×102 cfu/g to 6.5x104 cfu/g. Studies continue to portray lactic acid bacteria as the predominant group of microorganisms that have undergone several studies for food fermentation and have been used extensively as potential sources of probiotics for the production of functional foods

Assessment of surface bacteria contaminations and sensory quality of selected vegetable fruits exposed to pulsed X-ray irradiation

This study assessed the impact of pulsed X-ray irradiation on the bacteria contaminations and sensory quality of carrot and tomato. Fifty (50) kg each of carrot and tomatoes were collected into sterile sample polythene bags asceptically and were transported to the Food microbiology laboratory of the Ibrahim Badamasi Babangida University, Lapai for analysis. Bacterilogical quality assessment of the vegetable fruits were investigated using standard techniques. Carrot and tomato were exposed to different doses of 42, 50, 60, 67, 71, 75, 80, 85, and 90kv irradiation and non irradiated samples were analyzed microbiologically using pour plate technique. Odour, texture, color and general acceptibility of irradiated and non irradiated samples were analyzed by 20 trained panelies for sensory evaluation using 7 point hedonic scale. Different bacteria isolates from the surface of the carrot and tomatoes samples were observed culturally and microscopically. The result showed that carrot samples exposed to doses of 42,50, 67, 71, 75, 80 and 85kv and 90kv completely free of bacteria while tomato samples exposed to doses of 42, 50, 60, 67, 71, 75, 80, 85 and 90kv led to complete elimination of microorganisms present in the samples. Bacterial reduction rate of the exposed samples were directly propotional to the voltage and time exposed. There was gradual reduction in sensory profile of carrot within the voltage range of 5.0-3.5v and exposure rate of 42kv and 90kv. There was also a gradual reduction in sensory profile of tomato at the voltage range of 3.7-3.5v within the exposure rate of 42kv and 90kv respectively. The pulse x-ray is an effective non thermal treatment for vegetable fruits which could also preserve the sensory quality, however further studies are recomended to perfect this novel approach of food preservations

Assessment of bacteriological quality of well water around Dogon Dawa district in Birnin Gwari Local Government, Kaduna State

The inadequate supply of clean drinkable water and the frequent pollution of existing supplies have created very serious health problems for people living in developing countries like Nigeria. Water serves as a vehicle for the transmission of diseases like typhoid fever, botulism, diarrhea, dysentery, Schistosomiasis, ascariasis, acute severe syndrome etc. which have contributed immensely to the stagnation of the economic development of some of these nations. The assessment of bacteriological quality of well water was conducted to ascertain the quality of water consumed in the District. Water obtained from wells, streams and boreholes are not always chemically pure, even rain water contains dissolved materials from the air as well as suspended dust mixed with microorganisms. Twenty samples were collected from twenty different wells in four different areas that made up Dogon Dawa district. 100ml sterile bottles were used in collecting the water samples and capped carefully after transferring the water into the bottles, each bottle was assigned a code for easy identification, put into ice box and transported to Kaduna State Water Board Central Laboratory for analysis The Multiple tube fermentation technique was used to determine total coliform count and Eosin methylene blue was used to determine fecal coliform count. Some physicochemical parameters of the water samples such as turbidity, temperature, pH and dissolved oxygen (DO) were also determined. In all the 20 well water samples collected in Dogon Dawa district, there were very high bacterial count of between 26.20 -19.00 x102 cfu/ml which exceeded the recommended level of zero coliform/ml. The physicochemical parameters correlated with the bacterial contamination of samples. The turbidity of all samples of well water of between 8.0 - 9.0 NTU also exceeded the recommended level of 1.0-5.0 NTU. This study has shown that there is a high level of bacterial contamination of well water by pathogenic organisms in Dogon Dawa district. To reduce the high incidence of well water contamination, it is advocated that wells dug must be deep, far away from latrines and covered adequately.Keywords: Bacteriological Quality, Physicochemical Parameters, Assessment, Well Water, Dogon Dawa Distric

Physico-chemical analysis and sensory evaluation of bread produced using different indigenous yeast isolates

This study carried out the physico-chemical analysis and sensory evaluation of bread produced using different indigenous yeast isolates in order to offer an insight into the overall quality of the bread. Four (4) different yeast species were isolated from sweet orange, pineapple and palm wine. The yeasts were characterized and identified using the API 20C AUX kit. Each of the yeast isolates were used to ferment wheat flour dough. The specific volume, proximate analysis were carried out before baking. Commercial yeast served as positive control. The heavy metal analysis of the baked bread was investigated. The sensory evaluation of the baked bread was carried out with nine (9) point hedonic scale using ten (10) selected penalists. The yeasts were identified as Rhodotorula mucilagnosa, Rhodotorula minuta, Candida colliculosa and Candid krusei and the results of the physical properties obtained, showed that the bread sample CS2B had the highest specific volume (3.60cm3/g) while the negative control had the lowest value (2.03cm3/g). The proximate analysis of the bread samples revealed that the moisture content ranged from (0.2959-24.1), protein (3.325-5.425), fat (4.165-6.80), fibre (1.49-3.50), ash (1.331-3.1029), carbohydrate (43.325-89.112) and energy (256.20- 407.2298). The bread sample PW7B had the highest value of moisture (24.10), protein (4.90) and fat (7.45) while AC1B had the highest value of carbohydrate (89.11) and energy (407.23). No trace of lead and arsenic were found in all the bread samples, the value of iron, copper and calcium recorded falls within the permissible limit of FAO/WHO. The analysis showed that there was no significant difference (P>0.05) between the yeast isolates used to produce the bread and the perception of the different qualities of the bread. Generally, the bread samples were within the regulatory specifications of standard organisation of Nigeria (SON) and all the bread samples produced were generally accepted by the consumers in relation to their organoleptic properties. Fruits are excellent source of yeasts with dough fermenting abilities and bread of acceptable quality can be produced from these yeast isolates. The high proximate values of the bread samples recorded confirmed that they are capable of meeting most nutritional provisions as a staple food.Keywords: Yeast isolates, bread, physico-chemical analysis, sensory qualit

Comparative studies of rice wine production from synergistic and individual activities of lactic acid bacteria and yeast isolated from fermented foods

Rice wine is an alcoholic beverage of cereal produced as a result of saccharification and fermentation of rice, by action of microorganisms and enzymes. The comparative studies of rice wine production from synergistic and individual activities of lactic acid bacteria and yeast were investigated. Isolation and identification of LAB and yeast were carried out using API 50 CHL and API 20 AUX respectively, and the pure cultures of these isolates were inoculated at different concentration (50-50, 70-30, 100%) respectively into the rice substrate, and fermented for seven (7) days. The identified isolates were Lactobacillus plantarum and Candida krusei. Results obtained from the physiochemical and proximate analysis of rice wine after fermentation shows that alcoholic content of rice wine produced with C. krusei (100%) had higher value of 36.83% compared to rice wine produced with L. plantarum (100%) whose value was 4.52%. pH, total titratable acidity, and temperature after fermentation were between ranges of 2.4-4.5, 0.09-0.675 and 34oC-39oC respectively. The proximate analysis of rice wine indicates that, with L. plantarum and C. krusei (50-50) had a higher total soluble solids of 9.65% compared to rice wine produced with a (70-30) concentration, with the value 8.95% , rice wine produced with L. plantarum and C. krusei (70-30) has a higher moisture and energy content of 91.1% and 137.1kcal/g respectively compared to rice wine produced with yeast (100%) whose values were 90.8% and 79.2% kcal/g values respectively. Rice wine contains several organic acids which helps in the digestion of food and promotes better blood circulation and enhances body metabolism

Bacteriological quality assessment of ice cream sold in selected eateries within Kaduna metropolis

Ice cream is a frozen dairy product. Ice cream has an outstanding nutritional quality, but is also an excellent medium for bacteria growth. The study was conducted to evaluate the bacteriological quality of ice creams sold in selected eateries within Kaduna Metropolis. Fifteen (15) samples of ice cream were examined for proximate and bacteriological quality. The proximate analysis were determined for vanilla, strawberry and banana ice cream. Total viable count and coliform count were carried out on the ice cream samples using the pour plate technique, the samples were analysed by culturing on Nutrient, MacConkey and Salmonella-Shigella Agar media. Gram staining and biochemical test were carried to identify the organisms. The antibiogram of the selected antibiotics were evaluated against the organisms isolated. The proximate composition of moisture content was high in sample Y with 51.02%; Z sample had the highest ash content with 1.77%; sample Y and Z were both high in protein content with 7.41%. Sample X had a high crude fat content with 10.22%, sample Y was high in crude fibre content with 0.26% and sample Z was high in carbohydrate content with 30.28%. The total viable count ranged from 2.2x105to 24.7x105CFU/mL. The selected eatery from M site had the highest total viable count of bacteria while D had the lowest total viable count. The ice cream samples were contaminated with E. coli, Salmonella, Staphylococcus aureus, Klebsiella and Shigella species. E. coli and Staphylococcus areus which were observed in all the samples obtained from the sampling sites. The S. aureus was resistant to Spectinomycin at 10μg concentration. E. Coli and Klebsiella were more susceptible to the antibiotics used at different concentration. Pefloxacin, Gentamicin and Ciprofloxacin were observed to be the more potent antibiotics at 10μg concentration. The presence of the bacteria isolate lack proper hygienic conditions during preparation, preservation or serving of ice cream. These results suggest that consumption of these ice creams might cause GI disturbances, stomach abscess, diarrhoea and other diseases. The presence of potential pathogens in the ice cream samples revealed the significance of implementation of quality control measures in productive, storage and marketing ice creams thus reducing the public health hazards

Evaluation of food contact surfaces in selected restaurants of Kaduna State University for the presence of Escherichia coli and Staphylococcus aureus

The evaluation of food contact surfaces in Kaduna State University restaurants for the presence of Escherichia coli and Staphylococcus aureus were investigated. Five (5) selected restaurants in Kaduna State University were evaluated to assess the cleanliness of the surfaces that come into contact with food. Fifty (50) swab samples were collected from five (5) restaurants with three (3) samples each from plates, spoons and two (2) from chopping boards and tables. The samples were analysed using streak plate technique and biochemical tests to identify the bacterial isolates. Out of the 50 samples analysed, 13 (26 %) were positive for Escherichia coli and 0% was positive for Staphylococcus aureus. Out of the 13 that were positive for Escherichia coli, 8 (61.5 %) were from plates, 3 (23.1 %) were from chopping boards and 1 (7.7 %) was from table and spoon each. Eleven (11) (84.6 %) isolates of E. coli were susceptible to pefloxacin and tarivid each and 3 (23.1 %) isolates of E. coli were intermediate to septrin and ciprofloxacin each. While 6 (46.2 %) isolates of E. coli were resistant to amoxicillin and 7 (53.8 %) isolates of E. coli were resistant to sparfloxacin. This suggests that there is need for enlightenment of food handlers on the importance of good hygienic practices. Like introducing Hazard Analysis and Critical Control Point (HACCP) systems in food production and practices.Keywords: Contact surfaces, restaurants, swab, streak plate, hygienic practice

Comparative quality assessment of wine produced from green and purple grapes using Saccharomyces cerevisiae isolated from fermented milk

This research aimed at the comparative quality assessment of wine produced from green and purple grapes using saccharomyces cerevisiae isolated from fermented milk. The yeast was isolated using the pour plate technique and identified using cultural morphology, microscopic appearance, the carbohydrate utilization (sugar) test and ethanol tolerance test. Green and purple grapes were placed in different conical flask. The flask were designated as GGW and PGW for each sample respectively. Each sample (1000 ml) in the flask was inoculated with 2 ml 1.0 x 106 CFU of S. cerevisiae / mL , mixed with 0.2 ml 10% sodium metabisulfite, fermented for 5 days at room temperature, degassed and stirred daily, pasteurized at 60°C to stop the fermentation process and evaporated in a rotary evaporator at 60°C to remove the alcohol. Changes in temperature, pH, titratable acidity, volatile acidity, alcohol content, specific gravity (physicochemical parameters) were determined at intervals using standard methods. The must and the produced wines were subjected to several analysis. The produced wines were subjected to a proximate analysis, microbial analysis (total bacteria, coliform and total yeast counts) and sensory evaluated using nine-point hedonic scale by 10 experts (employees and students) and a shelf life of the produced wine were also determined. The yeast isolate was microscopically suspected to have the same colony morphology as Saccharomyces cerevisiae. As it was observed that glucose, maltose, fructose, galactose and sucrose were used up by the yeast isolates: The yeast isolate had an ethanol tolerance of up to 14%. The physicochemical parameters were relatively stable throughout the wine production process. The temperature ranged from 27°C - 28°C. The pH rose after fermentation. The specific weight decreased in all produced wines. Results of the proximate composition of green and purple grape wines showed varied percentages. The microbial analysis showed that bacterial isolates were dominated by yeast isolates. The sensory evaluation showed that both green and purple grape wine had an overall acceptance. The shelf life results showed that purple wine got spoilt faster than green wines. This study has shown that locally isolated yeast strains can be used to produce wines from locally available fruits which can yield good nutritional and microbiological quality