Natamycin and nisin to improve shelf life and minimize benzene generation in lemon soft drinks

Benzoic acids preservatives may be converted to benzene in soft drinks. The use of alternative antimicrobial compounds, specifically nisin and natamycin, would reduce benzene formation. Initially, doses of nisin and natamycin were tested against Lactobacillus plantarum lactic bacteria and Zygosaccharomyces bailii yeast. Using 167 UI/mL of nisin and 0.017% w/v of natamycin no microbial growth was reached on lemon-flavored soft drinks. The benzene formation was analyzed in a standard formulation (380 mg/L of sodium benzoate and 180 mg/L of potassium sorbate) and nisin and natamycn formulation (167 UI/mL of nisin and 0.017% w/v of natamycin). The soft drinks were stored without UV exposure at 20 °C and with UV sunlight exposure at 30 °C, for 120 days at PET bottles. The initial benzene content was 1.29 μg/kg for standard and 0.09 μg/kg for nisin and natamycin formulation; these values increased to 11.00 μg/kg and 0.18 μg/kg, respectively. The sensory attributes did not differ from each formulation, either initially or after 120 days of storage. The lower benzene concentrations obtained using nisin and natamycin suggest that these compounds are attractive alternatives to benzoic acids, keeping the sensory quality and microbial stability during shelf life.