Herbal medicines are a valuable and readily available resource for primary health care and complementary health care systems. Undoubtedly, the plant kingdom still holds many species of plants containing substances of medicinal value that have yet to be discovered; though large numbers of plants are constantly being screened for their antimicrobial effects. These plants may prove to be a rich source of compounds with possible antimicrobial activities, but more pharmacological investigations are necessary. The present study reveals the antibacterial potential of crude extracts of different parts of Rosa indica. Extracts from almost all parts of the plant showed antibacterial potential and produced zone(s) of inhibition thus; it should be further studied to determine the active component (s). Furthermore, Gram-negative bacteria were found to have more susceptibility as compared to Gram-positive bacterial species. This is probably due to the differences in chemical composition and structure of cell wall of both types of microorganisms. Data also showed that some antimicrobial substances could be extracted by organic solvents, suggesting that organic solvents are clearly better solvents of antimicrobial agents.

The prevalence of Arcobacter butzleri and Helicobacter pylori in some foods of animal origin and the possibility of their elimination by irradiation was studied. A. butzleri was isolated from 60 % of 20 whole chicken carcasses, 16.7 % of 24 ground beef samples, 40 % of 40 bolti fish samples and 45.5 % of 44 catfish samples. Meanwhile, H. pylori was not isolated from samples. Fresh samples of chicken breasts, ground beef, bolti fish fillets and catfish fillets were radiation sterilized and inoculated with A. butzleri or H. pylori at initial levels of 107 cfu/ g. Then samplers were irradiated at doses of 0, 0.5, 1, 1.5, 2, 2.5 and 3 kGy at room temperature and the survival of these pathogens was examined post treatments and during storage at 4 ±1 °C for 7 days. Irradiation at doses up to 1.5 kGy significantly decreased the counts of these pathogens, proportionally to the applied dose. Refrigerated storage had no significant effects on the counts of A. butzleri in control samples and those survived irradiation doses up to 1.5 kGy, whereas significantly decreased the counts of H. pylori. No colony forming units were observed for these pathogens in samples irradiated at dose of 2 kGy or above. The average D10 values were 0.26 and 0.28 kGy for A. butzleri and H. pylori, respectively. Therefore, irradiation at doses approved for treatment of fresh foods of animal origin may effectively eliminate the naturally present A. butzleri and H. pylori and prevent their possible hazards.

An attempt was made to isolate microorganisms from the industrial effluents and to study their role in bioremediation of lead in selected industrial effluents. Sixty bacterial strains from the industrial effluent were isolated, purified, preliminarily identified and examined for their ability to uptake lead. Based on the minimum inhibition concentrations (MICs) of lead for the selected isolates, six strains were found to be most resistant isolates and amongst them one isolate showed maximum resistance to lead which was identified as Bacillus cereus. Scanning electron microscopic (SEM) photographs and Energy dispersive X-ray spectroscopy (EDS) signature of Bacillus cereus revealed that lead was adsorbed to the cell surface, confirming biosorption capacity of the bacteria.