RESUMO
Aims: This study investigated the ability of bacteriocins isolated from Bacillus spp. (Bacillus species) to inhibit four different yeast isolates obtained from common food products (nono, yoghurt, ogi and cheese) commonly consumed by Nigerians with minimal heat treatment. Methodology and results: Forty-five Bacillus spp. was isolated and identified from common food products using cultural, morphological, physiological and biochemical characteristics. These isolates were tested for antimicrobial activity against Salmonella enteritidis (3), Micrococcus luteus (1) and Staphylococcus aureus (2). Eight bacteriocin producing strains were identified from an over- night broth culture centrifugated at 3500 revolutions for five minutes. Fungicidal effects of these bacteriocins were tested against four yeast strains using the Agar Well Diffusion method. The bacteriocins produced wide zones of inhibition ranging from 5.9±0.000 to 24.00±0.000 mm against the 4 yeast strains tested. There was a significant difference (at p<0.05) between the yeast organisms and the bacteriocins from the Bacillus spp. Conclusion, significance and impact of study: The study reveals the antifungal property of bacteriocins from Bacillus spp. and serves therefore as a base for further studies in its use in the control of diseases and extension of shelf-life of products prone to fungi contamination.
RESUMO
In Nigeria, inadequate supply of pipe borne water is a major concern; hence many homes have wells as a source of water for household uses. The groundwater of forty wells in Agbowo community was assessed for Total Aerobic Bacteria Counts (TABC) and Total Coliform Counts (TCC). The location and distances of wells from septic tanks were determined using the Global Positioning System (GPS) device and a tape rule respectively. All the wells sampled had high TABC (4.76±1.41 log CFU/mL) and TCC (2.29±0.67 log CFU/mL) counts which exceeded the international standard of 0 per 100 mL of potable water. There were no significant differences in the bacterial counts between covered and uncovered wells (p>0.05). The mean distance (8.93±3.61m) of wells from the septic tanks was below the limit (15.24 m or 50 ft) set by United State Environmental Protection Agency (USEPA). TABC increased with a decrease in distance between the wells and septic tanks though not significant (p<0.05). A very weak positive correlation (r2 =0.021) ensued between the distance from septic tank and CC, while a weak negative correlation (r2 = ‒0.261) was obtained between the TCC and TABC. This study accentuates the need to set standards for the siting of wells from septic tanks while considering all possible sources of well contamination as well as treatment of ground water before use.