[en] Threshhold dose for organoleptic changes by gamma irradiation in shell eggs is at 0.5 kGy, whereas frozen egg products is at 2.4 kGy and dehydrated egg products is at 3 kGy respectively. For the elimination of Salmonella, necessary dose is estimated to be 1 kGy for shell eggs and to be 2 kGy for dehydrated egg products from survival fraction of S. Typhimurium or S. Enteritidis. Contamination of Salmonella occur significantly in liquid egg products and for the reason of threshhold dose of organoleptic changes, irradiation treatment should be applied to dehydrated condition with 2-3 kGy. (author)

[en] The harmful effects of high-dose radiation on living organisms, including humans and animals, have been well-demonstrated through the findings of epidemiological studies of the effects of the atomic bombings in Hiroshima and Nagasaki and the Chemobyl nuclear accident Currently, a large number of studies are being conducted on the systemic effects of low-dose radiation these studies have been performed using both in-vivo and vitro systems. However, there have been few studies on the effects of low-dose (≤200 mGy) and low-dose-rate (LDR, ≤6 mGy/h) irradiation on spermiogenesis in small experimental animals. The effects of radiation on humans and animals are manifested in form of miscarriages, stillbirths, congenital malformations, and cancers: these effects occur as a result of genetic defects in paternal germ cells, It is well-known that genome instabilities in parental germ cells are spontaneously transferred to the next generation. However, it is difficult to precisely identify their response to radiation by using currently reported endpoint markers (apoptosis, gene mutation, repair capabilities, and chromosome aberrations of spermatogonia), since the testicles contain developmental stages of germ cells. Recently, we have conducted studies on the abnormalities of sperms in the caudal epididymis to investigate whether the genetic damage in the spermatogonial stem cells induced by LDR irradiation are transmitted to the next generation. Interestingly, our previous data showed that LDR (0.7 mGy/h) radiation does not damage spermatogonial stem cells and instead stimulates repair in these damaged cells in ICR mice. However, the relationships between the frequency of sperm abnormalities and the total accumulated dose with continuous LDR irradiation have not been investigated in Korean dark-striped field mice, A. a. coreae. In this study, we analyzed the frequency of sperm abnormalities in low- (0.7 mGy/h) and high-dose-rate (HDR, 0.8 Gy/min) irradiated Korean dark-striped field mice, A. a. coreae. We also determined the ratio of the dose-rate effect on the LDR γ-irradiated mice to that in the HDR γ-irradiated mice. This is the first report of the effects of radiation on spermatogenic cells in Korean dark-striped field mice, A. a. coreae

[en] Enterobacter sakazakii has been implicated as a causal organism in a severe form of neonatal meningitis, with reported mortality rates of 20%. The population at greatest risk is immunocompromised infants of any age. Dried infant formula has been identified as a potential source of the organism in both outbreaks and sporadic cases. The objective of this study was to investigate theirradiation effect of the inactivation on E. sakazakii (ATCC 29544) of a dehydrated infant formula. The D₁₀-values were 0.22-0.27 and 0.76 kGy for broth and dehydrated infant formula, respectively. The irradiation at 5.0 kGy was able to completely eliminate the E. sakazakii inoculated at 8.0 to 9.0 log CFU g^-1 onto a dehydrated infant formula. There was no regrowth for all samples during the time they were stored at 10 deg. C for 6 h after rehydration. The present results indicated that a gamma-irradiation could potentially be used to inactivate E. sakazakii in a dehydrated powdered infant formula