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Limited shelf life due to processing associated microbial contamination is one of the major challenging issues with minimally processed ‘Ready to Bake’ (RTB) vegetable products leading to huge post-processing losses. In the current study, three minimally processed vegetables, i.e. tomato, bell pepper and white onion, which are widely used in fast food industries (FFI), such as pizza and burger as well as in households; were studied for their post-processing microbiological profile; and to assess the effect of gamma radiation treatment (0.5–5 kGy) to maintain hygiene during extended storage at low temperature. Prior to radiation treatment, the minimally processed vegetables were packed in low density polyethylene bags (thickness: 50 μm) which is suitable for such agri-produce and compatible to gamma radiation treatment (USA, FDA). Besides, vacuum packaging in multilayered LDPE bags was optimized for shredded onion. Except tomato, which did not contain any detectable presumptive coliform or yeast and mold on day 0, the other two cut vegetables were found to have higher load of microbes, i.e., more than 4.0 log CFUg−1 of total aerobic plate count, 3.0 log CFUg−1of each of yeast and mold counts (YMC) and presumptive coliform (PC) counts. In the radiation treated (2 kGy) vegetables, no PC was detected; even after 20 days of storage; whereas, in the untreated bell pepper, tomato and onion samples PC counts were found to be 4.3 ± 0.1, 3.7 ± 0.2 and 1.7 ± 0.3 log CFUg−1 respectively on day 20 of storage. The data indicated that, the total aerobic plate counts in the 2 kGy irradiated samples were below the permissible limit as per the Food Safety and Standards Authority of India (FSSAI) guidelines. Organoleptic attributes (‘colour’, ‘texture’, ‘flavour’, ‘taste’ and ‘overall acceptability’) of the radiation treated products were found to be well retained even on 20 days of storage. The nutritional adequacy of these products in terms of total energy, fat, protein, carbohydrate, minerals and vitamin content was found to be well retained till the end of the 20 days' storage period. Findings of the study thus establish the efficacy of gamma radiation treatment in ensuring the safety and quality of minimally processed vegetables for their use in FFI as well as domestic kitchens.

As mutation causes many life-threatening diseases including cancer, a diet enriched with specific vegetables having potential to reduce mutagenesis possesses immense significance. In this study, 41 commonly used vegetables from diverse botanical taxa were evaluated and compared for their relative antimutagenic potential using standard assays [Escherichia coli RNA polymerase β (rpoB)-based Rif(S) → Rif(R) assay and Ames test] against known mutagens (UV, gamma radiation, 4-nitroquinoline-N-oxide and ethylmethanesulphonate). Significant differences in antimutagenicity were observed even among the cultivars within the same species, as well as at other phylogenetic levels such as genus or family. The effect of cooking in terms of boiling (aquathermal treatment), on the antimutagenicity of these vegetables, was also investigated. In majority of the cases, aquathermal treatment did not affect the antimutagenic potential. The antimutagenicity of these vegetables was not found to correlate well with their antioxidant properties.

Litchi, being a highly juicy and nutritious fruit, has very short life at ambient temperature, mainly due to microbial spoilage. The fruit soon loses its appeal because of pericarp browning due to anthocyanin degradation and enzymatic oxidation of phenolics. A sequential dip treatment, including sodium hypochlorite (0.2%, 4 min, 52 °C), potassium metabisulfite (3%, 30 min, 26 °C), and hydrochloric acid (0.25 N) containing ascorbic acid (2%, 10 min, 26 °C), followed by gamma irradiation, helped in overcoming this problem confronting trade. Dip treatment reduced polyphenol oxidase activity by ∼85%, retained major anthocyanins, cyanidin-3- O -rutinoside and cyanidin-3- O -glucoside by ⩾82% and 97%, respectively, and reduced microbial load to below detectable limits. Shelf life of processed ‘Shahi’ and ‘China’ varieties, at 4 °C, was found to be 45 and 30 days, respectively, whereas, unprocessed fruits spoiled within 15 days. Processing helped in maintaining overall quality attributes and can expand market access of the fruit in non-producing regions.

Enzyme immunoassay is based on the application of enzyme for detection and quantification of specifically labeled immunocomplex. Greater specificity, cheapness, and independency on radioactive tracers have made enzyme immunoassay popular over alternative techniques for analyzing a variety of samples. Apart from purity, stability, and turnover number, however, the practicability of conjugating the enzyme and its effect on enzyme activity restricts the choice of enzymes. Current developments in this field include mechanization of execution; fabrication of sensitive optical detectors, amplification devices, and new solid matrices; automated computer-based multiplex systems; and integration of knowledge from other disciplines of science.

This study aims to understand variations in antimutagenic potential of vegetables, as observed in reduction of UV-induced mutation (RifS→RifR) in Escherichia coli cells. On further investigation, the juice of vegetables [eggplant (small-violet), pepper (hot Arbol), bean (French), and tomato] was found to suppress mutagenic SOS response as measured by cell filamentation, LexA degradation, and induction of defective prophage as per their antimutagenic potential. Cell filamentation which was observed in 25 and 60% of the UV- and gamma-induced cells, reduced to 2–8%, and 3–16%, respectively in the presence of the vegetable juice; moreover, LexA was also not significantly affected. Phage induction frequency reduced upto 76% compared to control UV-exposed cells. The antimutagenic effect was found to be partially dependent on recB, ruvB gene functions, and was independent of uvrA function. Phenolic compounds were found to be the major contributors to the observed antimutagenicity.