Gamma radiation treatment to ensure microbial safety of ready to bake (RTB) vegetable toppings/ fillers and retain their nutritional qualities during cold storage

Thermoluminescence and ATR-FTIR study of UVC-irradiated low-density polyethylene (LDPE) food packaging

This research aims to study the effects of ultraviolet C (UVC) radiation on low-density polyethylene (LDPE) food packaging. Main objectives include evaluating LDPE degradation and detecting UVC radiation using thermoluminescent dosimeters (TLDs) placed under LDPE samples. Results confirm accurate UVC detection after one hour of exposure, providing a useful tool for optimize food treatment procedures. ATR-FTIR spectroscopy analysis revealed subtle alterations (<8 % transmittance relative) in UVC-irradiated LDPE samples, including possible CH breakage (2910 and 2848 cm-1) and potential CC bond vibrations (1470 cm-1), among others. However, observed variations may stem from LDPE properties rather than entirely from UVC radiation. A comparative study of UVC-induced thermoluminescence (TL) emissions provided insights into various TLDs materials. TL kinetic analysis, using computerised glow curve deconvolution (CGCD) method, unveiled trap charge activation due to UVC exposure, including partial ionization, bleaching effect and photo-transfer (PTTL) processes. LDPE samples amplified UVC-TL responses, revealing intensity differences between the TLDs attributed to the PTTL process, accentuated by the lack of an annealing treatment. Additionally, chemical composition of the TL detectors such as, type, concentration, number, oxidation states and ionic radii of their dopants may influence UVC-TL response. Consequently, TL intensity ratios follow as: GR-200 (LiF: Mg, Cu, P) > TLD-100 (LiF: Ti, Mg) > TLD-400 (CaF2: Mn) > TLD-200 (CaF2: Dy). Thus, GR-200 detects ionizing radiation but cannot distinguish between ionizing and non-ionizing UVC radiation, while TLD-100 has limited effectiveness as a UVC radiation detector. In contrast, TLD-400 is suitable for detecting UVC radiation and TLD-200 emerges as the most favorable UVC detector, showing consistent response levels and minimal PTTL effect placed under the LDPE samples without the need of a thermal annealing treatment that makes the TLD-200 to be reusable in a low-cost measurement protocol.

Research progress on the application of different preservation methods for controlling fungi and toxins in fruit and vegetable

Fruits and vegetables are susceptible to fungal infections during picking, transportation, storage and processing, which have a high potential to produce toxins. Fungi and toxins can cause acute or chronic poisoning after entering the body. In the field of fruit and vegetable preservation, technologies such as temperature control, modified atmosphere, irradiation, application of natural or chemical preservatives, and edible films are commonly used. In practical applications, according to the types, physiological differences and actual needs of fruits and vegetables, suitable preservation methods can be selected to achieve the effect of preservation and control of fungi and toxins. The starting point of fresh-keeping technology is to delay post-harvest senescence of fruits and vegetables, inhibit the respiratory intensity, and control the reproduction of microorganisms, which is important to control the reproduction of fungi and the production of toxins. From the three directions of physical, chemical and biological means, the article analyses and explores the effects of different external factors on the production of toxins and the effects of different preservation techniques on fungal growth and toxin production in fruits and vegetables, in order to provide new ideas for the preservation of fruits and vegetables and the control of harmful substances in food.

Radiation processing of papad - A sustainable method to improve safety and shelf life

Papad is a popular traditional Indian snack food that is also consumed as an accompaniment to meals. The papad industry in India is predominantly a cottage industry, mainly run by women. Due to microbial contamination and infestation, papad has a shelf life of only a few months. However, increased domestic consumption and export requirements necessitate a longer shelf life. Chemical preservatives are generally added to increase shelf life. Our studies have shown that radiation processing (2 kGy) can be used to extend the shelf life. Unirradiated samples spoiled in three months with visible fungal growth and insect infestation. Irradiated (2 kGy) papad had a shelf life of one year, was sensorily acceptable, showed no microbial counts, and hence has great export potential.

Gamma radiation processing for extending shelf-life and ensuring quality of minimally processed ready-to-eat onions

Onions are always in high demand owing to various culinary as well as health protective properties and these days there is increased consumer preference for ready-to-eat or ready-to-cook onions. In this context, the current study was aimed to extend the keeping quality of minimally processed onions for an extended period while ensuring microbial safety as well as sprouting inhibition through an integrated approach. The optimized combinatorial approach included gamma radiation treatment (Dmin60 Gy), minimal processing (de-skinning and scooping) and packaging in trays wrapped with polypropylene (PP; 10 µm thick) film followed by storage at low temperature (4-6 °C, relative humidity RH 65-70%). The parameters like shelf life, physico-chemical (colorimetry, moisture), organoleptic and nutritional properties were comprehensively assessed and found to be well retained up to 30 days with moisture loss of ≤ 5% and overall acceptability rating of 7 on 9-point hedonic scale. Microbiological analyses confirmed absence of Salmonella spp in these stored onions thus ensuring microbial safety. Nutritional profiling including carbohydrate, protein, fat, energy, and ash content revealed no significant change due to the processing as well as during storage. Thus, the radiation processing of freshly harvested bulbs followed by minimal processing, packing in formulated package and storage under low temperature conditions were found acceptable up to 30 days in the ready-to-eat form. Current findings provide credible evidences ascertaining extended shelf-life as well ensuring microbial safety of processed onions for commercial utilization by the food industries.