Study on antimicrobial stability and application of Surfactin in food

The effects of temperature,ultraviolet,p H,salts and sucrose on biological stability of Surfactin were investigated.The results showed that in weakly acidic solutions,the antibacterial activity of Surfactin changed little with temperature. After being processed under p H6,100 ℃ for 20 min,the diameter of the inhibition zone for Micrococcus luteus was varied from 17.52 ± 0.22 mm to 16.44 ± 0.03 mm. While Surfactin was processed in the alkaline( p H8) at 60 ℃ for 20 min,which can highly inhibit its bioactivity,the diameter of the inhibition zone was varied from 15.75 ± 0.19 mm to 12.69 ± 0.26 mm. It completely lost activity after treatment of p H8,90 ℃. Ultraviolet inhibited the antibacterial activity,but the effect was not obvious,while sucrose and salt had no significant influence.The preservative experiment results showed that the effect of Surfatin was much better than Nisin in foods whose p H was higher than 5.5.Adding an appropriate amount of Surfactin the rice might extend the shelf life of 24 h and the suitable dosage of Surfactin for bread was 200~500 mg / kg.