Response of Bacillus cereus vegetative cells after exposure to repetitive sublethal radiation processing in combination with nisin

► Resistance of Bacillus cereus by repetitive γ-radiation treatment at 1 kGy alone or in combination with nisin at its maximum tolerated concentration was investigated. ► Relative resistance of B. cereus was significantly increased after the 4th irradiation. ► Resistance of B. cereus could be due to changes in the cell wall structure. ► Physiological changes in B. cereus were observed in radio-resistant bacteria. ► Nisin treated cells increased radio-resistance by repetitive irradiation treatment which was not demonstrated by plate counting method.