Microencapsulated probiotic bacteria protected from degradation by acidic aqueous solutions, high bile salt concentrations, elevated temperatures, and prolonged storage and having an increased anti-bacterial activity as compared to their non-microencapsulated counterparts. The microencapsulated probiotic bacteria comprise probiotic bacteria encapsulated in microcapsules. The probiotic bacteria comprise live Lactobacillus plantarum cells. Each of the microcapsules comprises a matrix of a gelled alginate. The matrix wholly envelops the probiotic bacteria within the matrix. An outer surface of the matrix has a coating consisting essentially of one vegetable oil selected from the group consisting of olive oil and canola oil, or an outer surface of the matrix is treated with sodium chloride. The microencapsulated probiotic bacteria have an average particle size of less than 1000 microns (μm) in diameter.