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

Abstract

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.