Neem oil-based coatings for postharvest preservation of fresh produce: A critical review of antimicrobial action, formulation advances, and translational challenges

Neem oil contains azadirachtin and nimbin. The potential of neem oil as a multifunctional bio-agent is considered because of increasing antimicrobial resistance and increasing demand for sustainable bioactive substances. This review differs from recent reviews that mainly list its bioactivities by taking a critical approach and focusing on the main gaps in knowledge and methodological limitations in the current understanding of its antimicrobial mechanisms. It acts by disrupting membranes, interfering with quorum sensing, inhibiting biofilms, and synergizing with antibiotics. The oil has activity against Gram-positive bacteria, Gram-negative bacteria, fungi and protozoa. Advanced formulations such as emulsions, nanocarriers, composite or functional coatings are used to overcome challenges such as low water solubility, volatility and instability. Neem oil is under investigation for biomedical and food safety uses including wound healing, skin care, dentistry, cancer treatment, active packaging, and postharvest preservation. This review, however, highlights important translational barriers—lack of standardisation, limited in vivo validation, and insufficient testing under real-world complexity (e.g., chronic wound biofilms, realistic food matrices)—that are typically missing in the literature. Directions for future research are discussed to provide a safe and more successful implementation of neem-oil-based products in health and food industries.