Food safety is a significant concern of every sector of the food industry. Survival of Escherichia coli O157:H7 with biofilm-forming potential in commercial food premises is a possible danger to consumers' health, especially in societies where most of the population depend on it for their daily meals. Preservation of fresh food quality being of utmost importance, new innovative means of inhibiting pathogenic microorganisms in foods are being evaluated to be effective at destroying microorganisms and preserving the physical and organoleptic properties. This study aimed to inhibit biofilm formation of Escherichia coli O157:H7 by food additives; sodium citrate, sodium nitrite and cinnamaldehyde. The isolate obtained was subjected to Gram's staining and various biochemical identifications and later confirmed by the latex agglutination test. The Escherichia coli O157:H7 was further subjected to a biofilm formation potential test on Congo red media. Antimicrobial susceptibility testing was conducted to obtain the susceptibility/resistance pattern of the isolate to the food additives. The MIC, MBC and time-kill kinetics effect was determined following CLSI 2017 guideline. The highest growth inhibition zone of 31 mm was exhibited by cinnamaldehyde, followed by sodium nitrite with 26 mm and sodium citrate with 13 mm. The MIC was determined to be 2.5 mg/ml for sodium citrate, 0.25 mg/ml for sodium nitrite and 0.125 µl/ml for cinnamaldehyde. Sodium citrate was found to be bacteriostatic between 6-8 hrs with 72.9 % reduction, sodium nitrite and cinnamaldehyde exhibit both bacteriostatic and bactericidal effects between 2-24 hrs with percentage inhibition of 65-90 % and 63-100 %, respectively. This study showed that sodium citrate, sodium nitrite and cinnamaldehyde exerted strong antimicrobial properties indicating their potential as suitable preservatives.
Isolation and identification of bacterial species associated with decayed, commonly eaten food are paramount to reducing the risk of infection among the populace of the institution. Fifty samples were aseptically collected from the food vendors and subjected to culturing and sub-culturing on nutrient agar. The colonies were then observed for morphological characteristics, followed by biochemical tests and gram staining to ascertain their tentative identity. The results indicated that Staphylococcus aureus (37.2%) has the highest occurrence, followed by Bacillus spp (18.6%), while Clostridium botulinum has a minor event (2.3%). The presence of these organisms could be attributed to the dirty and unkempt behaviour of the food handlers, which in turn will impose serious health hazards to the immediate community and consumers at large. To reduce the risk associated with these organisms, all personal hygiene measures and the materials involved in the cooking procedures should be sterilised and free from any form of organisms before the cooking process.
In this study, different species of fungi associated with oil and non-oil Garri were isolated at Mudalawal market, Bauchi State, Nigeria. A total of eight different samples were obtained inside a sterile container and transported to the microbiology laboratory at Abubakar Tatari Ali Polytechnic Bauchi state for analysis. Malt Extract Agar was used for the isolation and identification; about five fungal species were isolated and identified using the standard method of Microbiological techniques. Penicillium spp. (26.9 %) had the highest occurrence in oil and non-oil Garri, followed by Aspergillus spp. (23.1 %), and Rhizopus spp. (19.2 %) with Fusarium spp. and Mucor spp. having the minor frequency of 15.4 %. Higher fungal species were isolated from non-oil Garri compared to oil Garri samples. Moisture content recorded showed higher Oil Garri than in the Non-oil Garri. The fungi isolated were characterized and identified based on their morphological and colonial appearance. The results show that consumers are exposed to the risk of aflatoxin poisoning. Efforts should therefore be made to improve the quality of Cassava by addressing its handling and processing practices.
A three-tube scheme that comprised a urease tube, motility tube and a gluconate-nitrate composite medium tube was evaluated for its reliability in correctly predicting the identity of Klebsiella pneumoniae after six hours of incubation. A total of 33 strains were used to assess the scheme, of which 17 were laboratory stock cultures, 14 were fresh clinical isolates, and two were environmental isolates from soil samples. The three tubes were heavily inoculated to give a density approximating McFarland No. 7 turbidity standard, which is roughly equivalent to a bacterial suspension with a concentration of 21 x 108 organisms/ml. The three-tube scheme identified all the five strains of Klebsiella pneumoniae tested correctly, but it was only able to accurately identify 23 out of 28 strains that were not Klebsiella pneumoniae. The scheme falsely identified five test strains that were not Klebsiella pneumoniae. The scheme had a sensitivity of 100 %, a specificity of 82.1 %, a positive predictive value of 50 % and a negative predictive value of 100 %. The scheme should perform better if the distinctive colonial characteristics of isolates on MacConkey agar were considered when predicting making prediction about identity, and a stricter interpretation of the results provided by the scheme was adopted.
The research was conducted to isolate soil fungi and screen them for cellulase production using the zone of hydrolysis technique. Several fungi were isolated and characterised from soil environments of different locations using conventional microbiological methods. A total of six isolates were confirmed to be Penicillium chrysogenum, Emericella rogulosus, Aspergillus terreus, Aspergillus flavus, Aspergillus niger, Aspergillus fumigatus, all coded as BG1, BG2, BG3, BG4, BG5 and BG6, respectively. Fungal isolate BG5 has the highest percentage of occurrence (34.30 %), followed by SBG3 (22.86 %). The isolates were screened for cellulase production using the carboxymethyl cellulose (CMC) agar plate method. All the fungal isolates demonstrated cellulase production ability, with fungal isolates BG5 (18 mm) and BG3 (15 mm) having the highest diameter of zone of cellulose hydrolysis. The research reveals the potentiality of using locally isolated soil fungi for cellulase production.
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