The nano-sized avocado seed powder (nano-ASP) was prepared to integrate in stirred yogurt as highly nutritional agriculture's removal discarded. The particle sizing, nutritional composition and phenolic contents of nano-ASP were determined. Also, their effect as antimicrobial agent plus activation supplement for probiotics was evaluated. The stirred yogurt was prepared as carrier to supply vital nano-ASP to human using concentration 0.0, 1.0, 2.0, and 3.0%. All stirred yogurt treatments were evaluated physicochemical, color, microbiological loaded and sensory properties during 30 days. The contaminated stirred yogurt with A. niger was designated to confirm their antimicrobial influence. The data indicated that nano-ASP was located nanoscale with seven phenol components mainly methyl gallate, catechin, and ellagic acid. The strongest inhibitory zones were obtained 17, 16, and 19 mm for S. aureus, A. niger, and A. flavus, respectively at the concentration 1% and capable to increase the probiotic strains' proliferation. Moreover, the nano-ASP was considered the vigorous source for protein, carbohydrates, minerals, fiber with highly antioxidant activity that added nutrition healthy components to stirred yogurt. The viable counts of L. acidophilus loaded in stirred yogurt was improved during storage, especially at 2% nano-ASP that adequate to progress L. acidophilus for two weeks and as well amplified the starter cultures counts. Stirred yogurt with 1.0% and 2.0% nano-ASP received higher overall acceptability scores. In the contaminated part, the levels of A. niger increased more with storage under control than with other treatments. From results, the appropriate stirred yogurt shelf life was 21 days.