Investigation of Probiotic Chocolate Effect on Streptococcus mutans Growth Inhibition

Background: one of the most important factors in inducing the logarithmic growth ofstreptococcus mutans, is a diet containing fermentable carbohydrates such as sucrose.objectives: the aim of the current research was to compare the ability of ordinary andprobiotic chocolate to induce or inhibit the growth of s. mutans.materials and methods: lactobacillus rhamnosus, l. plantarum and l. acidophilus as probioticstrains, were cultivated on mrs agar for 24 hours at 35° c in 5% co2. s. mutans whichis a dominant factor in causing dental plaque, was isolated from 20 samples of dentalplaque and caries lesions in adults on streptococcus selective agar medium, and diagnosedby routine biochemical tests. the antimicrobial effect of three probiotic strains ons. mutans was evaluated by the deferred cross-streak method and susceptibility throughthe disk diffusion test. the antimicrobial effect of the probiotic supernatant powder wasdetermined by a dilution method. probiotic strains were added to dark chocolate witha concentration of 108 cfu/ml and their antimicrobial effect on s. mutans was evaluatedby the disk diffusion susceptibility method. survival of the probiotic strains in chocolateand ph shifts were studied in different environmental storage conditions.results: the results showed that s. mutans was the dominant strain in all of the 20 dentalplaque samples. l. plantarum showed the most antimicrobial effect on s. mutans with themaximum diameter of growth inhibitory zone, 35 mm and 78 × 78 mm in the disk diffusionmethod and deferred cross-streak method, respectively. probiotic supernatant powder inhibiteds. mutans strains in concentrations of 500-700 and 100-300 mg/ml at t = 0 and t = 24,respectively. comparing the results in terms of maintenance and storage of probiotic chocolate,it showed that the best condition to keep this chocolate is at 4? c (refrigerated) with aprobiotic survival of 25 to 30 days. the ph level during this period decreased from a ph of 5 to4. probiotic chocolate containing l. rhamnosus was shown to have the greatest antimicrobialeffect on s. mutans with a maximum diameter of growth inhibitory zone of 75 mm during 59days storage at an ambient temperature and 4° c.conclusions: these results suggest that probiotic chocolate is able to inhibit the growthof s. mutans rather than ordinary chocolate.