Biofilms are biological barriers produced by a variety of organisms either for defense or because of physiological processes.

Consumers’ demand for minimally processed fresh minimally fruits and vegetables owing to their reputation of being convenient, fresh, nutritive, healthy, and cheap has been on the increase over the years. Contamination of these commodities during processing has been reported and vendors often ignore proper hygienic processes. However, since fresh produce is often consumed raw, these products could harbor potentially pathogenic bacteria. In this study, 15 randomly selected samples of fresh, minimally processed watermelon, cucumber and garden egg were collected from markets in southeastern Nigeria and evaluated by way of standard plate techniques of serial dilution for bacterial contaminants. Following standard bacteriological practices, dilutions were plated on suitable growth media and incubated for 48 h. Pure cultures of bacterial isolates were investigated for total viable counts and identified both macroscopically and microscopically via Gram staining technique, spore staining technique, motility test and biochemical analysis. Fifty-eight isolates were obtained and the total viable plate count from all samples ranged from 1.0×10⁶-8.0×10⁶ CFU/g with watermelon samples recording the highest volume of bacteria loads. The cultural and biochemical characterization revealed the presence of seventeen (17) probable species of bacteria: Staphylococcus aureus (40%), Bacillus sp.(21%), Escherichia coli (18%), Staphylococcus epidermidis, Corynebacterium sp., and Citrobacter sp. (17%), Lactobacillus sp., and Proteus sp.(12%), Yersinia sp., Serratia marcescens, Listeria sp. and Pseudomonas sp.(6%), Klebsiella sp., Streptococcus sp., Bacillus cereus and Clostridium sp. (5%), and Salmonella sp. (2%). Probable pathogenic bacteria exceeded the standard limit thus requiring urgent public sensitization and education by appropriate regulatory agencies. Therefore, the consumption of these minimally processed fruits and vegetables couldlead to foodborne infections.

Citrus plants are vital sources of essential oils, both for food and for therapeutic purposes. This study aims to assess the antibacterial properties and Gas chromatography-mass spectroscopy profile of essential oils derived from citrus lemon peel. Lemons were sourced from local vendors, and essential oils were extracted from the peel using steam distillation. Standard methods were employed for qualitative phytochemical analysis, while the anti-microbial activity of the crude oil extract was tested against a clinical isolate of E. coli. Chemically, the components of crude oil extract were analyzed using GC-MS. An extraction yield of 8.28 % was achieved. Phytochemical screening indicated the presence of secondary metabolites such as terpenoids, polyphenols, saponins, tannins, and flavonoids, The antimicrobial assay demonstrated that both the crude extract and positive control (metronidazole 200µg/ml) exhibited significant inhibitory activities against Escherichia coli. Out of the total essential oil, forty-five (45) chemical components were identified. Limonene having a percentage of 40.07 was the most prevalent constituent. Other constituents included: Gamma Terpinene (11.48 %), β-Pinene (10.11 %), α-Terpineol (8.50 %), α-Pinene (3.80 %), Myrecene (1.57 %), Geraniol (1.50 %), α-Terpinene (1.42 %), α-Terpinolene (1.37 %), Linalool (1.22 %), and cis-α-Bergamotene (1.09 %). The GC-MS analysis highlighted Limonene as the most abundant component in citrus lemon essential oil. This study reveals the potential antibacterial property of essential oils from C. limon peel against E. coli. Keywords: Essential oil, Lemon peel, Gas chromatography-mass spectroscopy, Antibacterial activity.

The unique physicochemical properties of nanoclusters, including ultrasmall size, tunable surface chemistry, high surface-to-volume ratio, and distinctive optical behavior, enable their use in the diagnosis and treatment of bacterial, viral, fungal, and parasitic infections.