The antimicrobial activity of various plant extracts on Pseudomonas bacteria isolated from spoiled chilled tilapia (Oreochromis sp.) was evaluated in this study. In the first stage of this study, red tilapia was subjected to chilled storage (4°C) for 3 weeks, and spoilage bacteria were isolated and identified from the spoiled fish. Pseudomonas was the dominant bacteria isolated from the spoiled fish and further identification revealed that P. putida, P. fluorescens and Pseudomonas spp. were the main species of this group. In the second stage, methanolic extracts of 15 selected plant species were screened for their antimicrobial activity, by agar disc diffusion method, against the Pseudomonas isolates. Results indicated that most of the extracts had different degrees of activity against the bacterial isolates. The strongest activity was exhibited by bottlebrush flower (Callistemon viminalis) extract. This was followed by extracts from guava bark (Psidium guajava) and henna leaf (Lawsonia inermis). Moderate antimicrobial activities were observed in extracts of clove (Syzygium aromaticum), leaf and peel of tamarind (Tamarindus indica), cinnamon bark (Cinnamomum zeylanicum), wild betel leaf (Piper sarmentosum) and fresh thyme (Thymus spp.). Weak or no antimicrobial activity was observed from the remaining extracts. The potential antimicrobial activity shown by some plant extracts in this study could significantly contribute to the fish preservation.

This study explores the phytochemical composition and antibacterial properties of aqueous and methanolic extracts of Anastatica hierochuntica against foodborne pathogens and clinical isolates. Phytochemical analysis identified key compounds, including alkaloids (7.15 ± 0.0365 mg/g), flavonoids (3.16 ± 0.007 mg/g), and tannins (0.18 ± 0.0025 mg/g). Food samples yielded Escherichia coli isolates, Staphylococcus aureus, Staphylococcus epidermidis, Salmonella typhi, and Serratia marcescens. The antibacterial efficacy was assessed using the agar well diffusion method against these pathogens and clinical isolates, including Pseudomonas aeruginosa and Klebsiella pneumoniae. The aqueous extract demonstrated strong antibacterial activity against all food pathogens, with Staphylococcus aureus, Salmonella typhi, and Serratia marcescens exhibiting the largest inhibitory zones (34 mm). Among clinical isolates, only Klebsiella pneumoniae and Pseudomonas aeruginosa showed selective inhibition. Conversely, the methanolic extract was largely ineffective, displaying activity only against Serratia marcescens (average inhibitory zone of 11.7 mm). These results underscore the potential of A. hierochuntica aqueous extracts as a natural antimicrobial agent and suggest further investigation into its bioactive compounds for improving food safety and addressing multidrug-resistant pathogens.

Study on toxigenic mycoflora and potential mitigation effect of Christmas Melon (Laganaria Breviflorus) extract in unpolished rice sold in Abeokuta Ogun state of Nigeria was carried out. Unpolished rice gotten from markets in Abeokuta were aseptically transported to the laboratory, serial dilution to reduce the fungal load was carried out and were plated on Potato Dextrose Agar (PDA) and Methyl Red Dessicated Coconut Agar (MRDCA) respectively. Microscopy, macroscopy, toxigenicity test and inhibition studies with the peeled and unpeeled fruit of Laganaria breviflorus fermented for seven days was carried out. Results reveal the predominance of Aspergillus as the major genera, specifically, A. niger, A.flavus, A. parasiticus, A. fumigatus, A. terreus, A. nidulans. Other fungi genera isolated include Penicillium, F`usarium, Mucor, Alternaria and Rhizopus . Of the 11 fungi genera isolated, 9 were toxigenic of which the zones of inhibition of unpeeled whole fruit extract of Laganaria breviflorus range from (3 - 28mm) where A. nidulans shows the highest susceptibility to the whole fruit extract of Laganaria breviflorus while the zone of inhibition of peeled fruit extract of Laganaria breviflorus ranges from (3 - 22mm) where A. parasiticus, Fusarium specie and P.chrysogenum showed the highest susceptibility . As the day progresses the zone of inhibition becomes wider. Unpeeled LB extract exhibited more zones of inhibition than the peeled LB extract. Laganaria breviflorus fruit extracts in the study demonstrates a potential in reducing toxigenic fungi, consequently a means to reducing mycotoxins in staple foods in Nigeria.

Xanthomonas axonopodis pv. phaseoli (Xap) is known as one of the most important seed-borne destructive pathogens on beans worldwide. Nowadays, Xap is considered to acquire resistance to antibiotics and synthetic bactericides which concerns the scientific world for its future management. This has made the use of plant extracts, the best alternative in the control of plant disease pathogens by inhibiting the quorum sensing (QS) mediated virulence factors. This research was designed to investigate the antibacterial activities and the anti-QS effects of the 14 different aromatic and medicinal plants against QS-mediated virulence factors of Xap. The results revealed that Syzgium aromaticum showed the largest inhibition zone diameter and strongest antimicrobial (antibacterial) effect among the 14 plant extracts followed by Thymus vulgaris and Coriandrum sativum. Similarly, the lowest swarming, swimming, and twitching motility values were measured from the Syzgium aromaticum application followed by Coriandrum sativum, Thymus vulgaris, Brassica nigra, Lepidium sativum, and Ruta chalepenis. These results indicated that S. aromaticum, C. sativum, T. vulgaris, B. nigra, L. sativum, and R. chalepenis will be a potential candidates as anti-quorum sensing agents in preventing common bacterial disease of beans caused by Xap. Compounds derived from aromatic and medicinal plants have demonstrated successful control of diseases in crops and the use of these substances provides a valuable tool to the growers around the world for diseases management in organic production.