Hurdle Technology Including Chlorination, Blanching, Packaging and Irradiation to Ensure Safety and Extend Shelf Life of Shelled Sweet Corn Kernels

Abstract

Shelled sweet corn kernels are prone to microbial contamination, making it highly perishable and unsafe. In freshly shelled kernels, total aerobic plate count, yeast mold count and presumptive coliforms were ∼8, 7 and 4 log cfu/g, respectively. IMViC (indole-methyl red-Voges–Proskauer [VP]-citrate) analysis confirmed the presence of opportunistic pathogens such as Escherichia coli and Enterobacter aerogenes. A combination process including NaOCl wash (200 ppm), hot water blanching (60C), followed by gamma irradiation (5 kGy) reduced the microbial load to below detectable level (<2 log cfu/g) and maintained it within permissible level up to 30 days at 4C. However, these treatments alone were not found to be very effective. Total sugars (∼1 g/100 g), reducing sugar (∼0.58 g/100 g), protein (∼0.6 g/100 g), phenolics, flavonoids, antioxidant capacity (33%), antimutagenic potential (43%), physical properties and sensory qualities of combination processed samples during storage were found to be similar as those of fresh samples (control). Developed combination process ensured safety and extended the shelf life of kernels. Practical Applications Shelled sweet corn kernels are a highly perishable food commodity due to frequent postharvest contamination. A technology based on combination of hurdles was developed to extend its shelf life and ensure microbiological safety while retaining nutritional, sensory and health protective properties during extended storage up to 30 days.