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 APPLICATIONSShelled 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.

Identifying suitableListeria innocuastrains as surrogates forListeria monocytogenesfor horticultural products

“…In general, the synergistic hurdle effect of the three combined treatments was mirrored in both the individual strains and the cocktails. Although hurdle technology has been applied to different fresh-cut-produce and food products (41, 56, 57), our laboratory-based hurdle study cannot be compared with these studies as they involved different treatments as combinations including spray washing, essential oils, high-pressure processing, sonication and other as suited for different food products.…”

Fruits and Vegetables as Dietary Sources of Antimutagens

“…This assay is advantageous due to its simplicity in deployment, the ability to provide a wide spectrum of forward mutations and low level of spontaneous mutations (approximately 1/10 8 cells) ( Figure 1). It has been extensively used recently to screen the antimutagenic potential of different foods particularly fruits, vegetables and other allied food products at Food Technology Division, Bhabha Atomic Research Centre, Mumbai, India (Figure 2) [20,[50][51][52][53][54][55][75][76][77][78][79]. The assay is better for scoring antimutagenicity over mutagenicity.…”

“…In one study, boiling of various dialysate of vegetables was not found to affect the antimutagenic activity against Trp-P-2 [130]. Sweet corn processed using chlorination, blanching, and gamma radiation was reported to display similar antimutagenic activity similar as of fresh control in Rif R assay [78]. Thus, most studies have indicated high stability of antimutagenic principle toward different processing.…”

An Improved Combination Treatment for Ensuring Safety and Extending Shelf Life of Sweet Corn Kernels

“…Ascorbate (0.25, 5, and 1%) was solubilized in sterile water and the temperature of the solution was maintained at 4 º C. The kernel was dipped in the cold ascorbate for different time points (2.5, 5, and 10 min). The treated samples were air dried in hygienic and aseptic condition for 2 h as standardized in our earlier study [4]. Later, the samples were vacuum packed (30,45, and 60%) in sterile LDPE (175 gauge, permeability of CO 2: ~17,600 ml/m 3 /day and O2: ~3050 ml/m 3 /day) packets and gamma irradiated at 2 kGy in a cobalt -60 food package irradiator (AECL, Ottawa, Canada; dose rate: 40 Gy/min) at this institute [4].…”

“…The treated samples were air dried in hygienic and aseptic condition for 2 h as standardized in our earlier study [4]. Later, the samples were vacuum packed (30,45, and 60%) in sterile LDPE (175 gauge, permeability of CO 2: ~17,600 ml/m 3 /day and O2: ~3050 ml/m 3 /day) packets and gamma irradiated at 2 kGy in a cobalt -60 food package irradiator (AECL, Ottawa, Canada; dose rate: 40 Gy/min) at this institute [4]. Dosimetry was performed using a standard cerric-cerrous (3 mM) dosimeter [20].…”