Evaluation of few bioactive components of spice origin for their antimicrobial potential towards microbes commonly implicated in food spoilage and foodborne pathogenesis

Abstract

Natural components isolated from spices are gaining the attention of food researchers to prevent the growth of microbes associated with food spoilage and foodborne pathogenesis to meet the ever-increasing consumers’ demand for safe and wholesome food free from harmful synthetic preservatives. In the present study, five bioactive components of spice origin, namely, allylisothiocyanate (AITC), cinnamic aldehyde (CIA), cuminic aldehyde (CUA), eugenol (EU), and menthol (MT) were evaluated for their antimicrobial potential towards six bacterial strains (Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Pseudomonas alcaligenes, Shigella sonnei, Staphylococcus aureus) and eleven fungal strains (Alternaria solani, Aspergillus niger, Botrytis cinerea, Cladosporium herbarum, Fusarium oxysporum, Geotrichum candidum, Penicillium citrinum, Penicillium expansum, Phoma exigua, Rhizopus arrhizus and Rhizopus stolonifer), by opting agar well diffusion assay, impregnated paper disc method and broth dilution technique. All these seventeen microbes pose deleterious effects on food and human health. Among the bioactive compounds, CIA and CUA turned out to be the most potent inhibitors of microorganisms, whereas MT was found to be the least effective. Lower concentrations of bioactive components, ranging from 1.95 µL/mL to 15.62 µL/mL, were needed to inhibit fungi, while higher concentrations ranging from 15.62 µL/mL to 1000 µL/mL were needed to inhibit bacterial strains. Among the bacterial strains tested, gram-negative bacteria were inhibited at higher component concentration levels (31.25 µL/mL-1000 µL/mL) compared to gram-positive bacteria. The present study updates the existing information on the antimicrobial potency of natural substances, paving the way to further research on establishing spice bioactive components as ‘natural additives’.