Efficacy of Gamma Irradiation in Improving the Microbial and Physical Quality Properties of Dried Chillies (Capsicum annuum L.): A Review

Dried chilli is one of the highly traded spices globally and is well-known for its natural flavour, colour, and unique pungent taste. It is rich in nutrients and has medicinal benefits. During the dehydration and storage process, the proliferation of unwanted microorganisms in dried chilli is unavoidable. Recently, the occurrence of toxigenic fungi and faecal coliforms has been widespread that can cause severe illness and even death. Therefore, sanitation treatment is highly required to decontaminate undesirable microorganisms. Among the common sanitation treatments applied, food irradiation is gaining attention worldwide because of concern for post-harvest loss, foodborne disease, and more stringent regulation in dried chilli trading. Irradiation can successfully preserve dried chilli from pathogenic bacteria with minimal disturbance to critical physical properties, such as pungency and colour. It can also save dried chilli from secondary pollution by storing it into final packing before radiation which helps in distribution to market promptly after treatment. Furthermore, radiation does not leave any chemical residues after the treatment, ensuring the quality and safety of the dried chilli. The efficiency of radiation depends mainly on the initial level of contamination and the persistence of the harmful microorganism. A low irradiation dose is sufficient for dried chili to reduce microbial load to an acceptable level and eliminate pathogens even though a minimum radiation dose of 10 kGy is required for complete sterilization. However, high dosage may affect the colour properties. Gamma radiation, X-ray, and electron beam radiation are the three approved radiation sources for dried chilli in most countries and proven effective for dried chilli preservation. Thus, this review paper highlights the microbial and physical quality properties in gamma radiated dried chillies.

Effect of Irradiation process on mango

Mango (Mangifera indica L.) is one of the choicest tropical fruit of the world and rightly designated as "King" of all fruits. It is a nutritionally important fruit being a good source of vitamin A, B and C and minerals. Post-harvest losses in mangoes have been estimated in the range of 25 to 40% from harvesting to consumption stage. Improved practices and preservation have a great impact on retaining mango fruit quality and on the supply chain. Nowadays food irradiation process is an engrained technology for the preservation of foods and food products. Three different kinds of ionizing radiation are applicable for food irradiation processes (Gamma-rays which is emitted from the radio-isotopes Cobalt-60 and Caesium-137, or electron beams and X-rays). Food irradiation can be considered an evolving technique that is capable of increasing the shelf-life, deferring the ripening and senescence of fruits, and thwart of microorganism activity along with insect infestation. Irradiated food is save for human health. This review article is focusing on irradiation effects on mango and the adoption of improved practices by the farmer for export besides that of food safety.

Intercomparison of Gamma Cell 220 Irradiator Facilities and Dr. Mirzan T Razzak Gamma Irradiators Using Harwell Dosimeters

The gamma irradiator is a multi-purpose facility that possibly used to preserve food, sterilize medical equipment, and conduct genetic engineering and polymerization processes, during which the absorbed dose of the product is critical. The standardization of product quality assurance was regulated by the IAEA Technical Document Number 409 considering Dosimetry for Food Irradiation and ISO 14470 and 11137-3 on Food Irradiation, as well as the Guidance on Dosimetric Aspects of Development, Validation, and Routine Control, respectively. The absorbed dose was influenced by the movement of the product to the source, its position, the amount of radioactive activity in the facility, and the dose rate in the irradiation room. The dosimeter performance test and quality assurance of the system were conducted using the Facility Intercomparison Technique which tested the dosimeter (measuring instrument) at 2 different facilities to determine the performance of the measuring instrument.. In this study, 2 irradiation facilities were tested using a Harwell routine dosimeter in the dose range of 1 kGy to 30 kGy and 20 dose points. The results showed that the highest deviation reached 19% and 21% at the Gamma Cell 220 and the Dr. Mirzan T Razzak Gamma irradiator facilities. This elevated the performance of the dosimeters to determine the precision accuracy of the dose-measuring instrument.

Assessment of aerobic bacteria killing activity of low energry X-rays in potatoes

Potato is one of popular agricultural products grown and used in the world with high effective economic and nutritional value. In potatoes, there are always have some harmful bacteria species due to the sources of exposure from the seed, soil as well as the post-harvest environment which make deceasing the quality and quantity of potatoes. Usually, irradiation with gamma isotope sources is used in food irradiation, however, the disadvantage of the gamma source is the safe shielding reason even without the use of irradiation. Nowadays, X-ray irradiation in food is one of the methods interest to storage in long time. The first advantage of X-ray irradiation is that most of aerobic bacteria in food is killed, but does it not change the quality of the potato. Moreever, the advantage of an X-ray generator is that it does not have to cover up radiation when not in use. In this study, we have used low energy X-rays emitted from X-ray generator MBR-1618R-BE (Hitachi -Japan) to study the ability to kill aerobic bacteria in potatoes grown in Da Lat. After preparation, potato samples were irradiated at doses ranging from 50 Gy to 5000 Gy. The irradiated samples were homogenized and inoculated on Nutrient Agar and incubated at 370C in an incubator to check the changes of aerobic bacteria. The research showed that the number of aerobic bacteria decreased dramatically to a dose of 1000 Gy (the aerobic bacteria was only less than 0,6%), despite a sharp increase in the dose of irradiation, this number decreased a little. The results also showed that D10 dose was 471,34 Gy.

EFFECT OF IRRADIATION IN HONEY INOCULATED WITH Bacillus sporothermodurans

Honey is a natural viscous product widely used for nutritional and medicinal purposes. Although it’s a food that presents a high degree of resistance against the growth of microorganisms is not a sterile medium. Spore-forming bacteria, such as Clostridium botulinum, are present in honey and it’s the only recorded source of food carrier of the agent that causes childhood botulism. The steps of honey processing do not include the heat treatment for its commercial sterility, due to the application of heat increase the presence of hydroxymethylfurfural. Food irradiation is a method of preservation that can be applied in the processing of honey by not physically altering the appearance, shape or temperature of the product. The objective of this work was to evaluate the effect of gamma irradiation on honey inoculated with Bacillus sporothermodurans spores. The inoculation of 106 CFU.mL-1 of lyophilized culture of this bacterium in the honey samples was carried out and the irradiation of the samples at 5, 10 and 15 kGy doses was carried out. After irradiation, the samples were incubated at 30o C for 72 h in Brain Heart Infusion (BHI) agar. The count present reduction of one logarithmic cycle in the number of colonies in the 5 kGy irradiated honeys. In the samples irradiated with doses of 10 and 15 kGy there was no microbial growth and spore germination. It’s concluded that irradiation constitutes an excellent conservation method, which can be used to guarantee the microbiological quality of the honey.