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[en] Radiation disinfection of manure for animal feed supplement. Radiation treatment for disinfection of manure have been investigated on manure collected during the dry and rainy seasons. Total bacterial counts of non-irradiated dewatered manure with water content of around 13.44% were found to be 1.0x106 up to 1.4x108 per g during the dry season, and 2.0x105 up to 1.7x107 per g during the rainy season, while coliforms, enterobecteriacease, staphylococcus, streptococcus, and pseudomonas were found to be 1.0x106 up to 1.4x108 per g, 1.0x104 up to 1.2x106 per g, 4.0x105 up to 2.2x107 per g, 1.8x103 per g, and 1.0x102 up to 5.4x103 per g, respectively. About 30% of the total coliforms were found to be escherichia coli. Irradiation dose of 4 kGy eliminated salmonella from all samples observed. No. Shigella Vibrio, and parasites were detected in the samples. Total nitrogen of the dewatered manure ranged between 1.87 and 2.33%, phosphorus between 1.25 and 4.38%, and potassium between 0.66 and 2.18%. Heavy metal elements were found only in very small amounts, hence the dewatered manure could be applied as animal feed or soil conditioner. A combination of irradiation at 4 kGy and storage for 3 months was synergistically effective to eliminate coliform, E. coli, and salmonella in the dewatered manure. From nutritional point of view, the manure is still acceptable for animal feed supplement. (author). 13 refs
[en] There is increasing usage of honey as a dressing on infected wounds, burns and ulcers, but there is some concern that there may be a risk of wound botulism from the clostridial spores sometimes found in honey. It is well-established that the antibacterial activity is heat-labile so would be destroyed if honey were sterilized by autoclaving , but the effect of gamma-irradiation on the antibacterial activity of honey is not known. Therefore an investigation was carried out to assess the effect on the antibacterial activity of honey when the honey was subjected to a commercial sterilization procedure using gamma-irradiation (25 kGy). Two honeys with antibacterial activity due to enzymically-generated hydrogen peroxide and three manuka honeys with non-peroxide antibacterial activity were investigated. The honeys were tested against Staphylococcus aureus in an agar well diffusion assay. There was no significant change found in either type of antibacterial activity resulting from this form of sterilization of honey, even when the radiation was doubled (to 50 kGy). (Author)
[en] Originally, the VDmax approach was developed to substantiate a selected sterilization dose of 25 kGy. Thereafter, computer and field evaluations demonstrated the value of the approach for substantiation of selected sterilization doses less than 25 kGy. Verification of the use of the approach for substantiation of sterilization doses in excess of 25 kGy is now needed. The results of the computer evaluations conducted on the VDmax approach with 35 challenge microbial populations at sterilization doses of 30 and 35 kGy generally gave outcomes consistent with those observed previously, namely, safe and unambiguous. Outcomes perceived as unsafe have been shown to be a peculiarity of the manner of assembling challenge microbial populations. Field evaluations involving substantiation of four selected sterilization doses greater than 25 kGy and associated sterilization dose auditing gave acceptable outcomes. The present findings further affirm the value and reliability of the VDmax approach.
[en] After radiation sterilization, it is always necessary to demonstrate that any products formed in the irradiation are not harmful. The amounts of products formed in the gamma-irradiation of solid samples may be so small, that standard toxicity tests could be ineffective. Hence, analysis of the final products in the radiosterilized solid samples might be required. In this work, some chloramphenicol degradation products that are unique to radiolysis, i.e. different from the normal degradation products, were detected. (author)
[en] A spike in a set of bioburden data can be considered a bioburden number or numbers that are several times greater in value than the average value of the data set. A spike is not considered a manifestation of a quality issue, but a consistent component of product bioburden that should be taken into account in establishing the minimum acceptable dose in the radiation sterilization process. Rather than a subjective approach, statistical techniques were used to determine when a bioburden number or numbers represent spikes in a set of bioburden data. Bioburden data taken from a cross section of different products over a few months were analyzed. Results of the study identified spikes when the spike bioburden was approximately three or more times the average bioburden for the data set. In those cases where bioburden spikes were identified, use of the spike bioburden rather than the average bioburden increased the sterilization dose by up to 10%.