Radiation Sterilization of Prototype Military Foods. III. Pork Loin

Ten lots of pork loin, packed in cans, were inoculated with approximately 10(6)Clostridium botulinum spores per can. Each lot was seeded with a different strain; five type A and five type B strains were used. The pack comprised 5,690 cans, including controls, and contained about 10(9) spores per dose. The cans were irradiated with Co(60) in the range of 0 to 5.0 Mrad (0.5 Mrad increments) at 5 to 25 C, incubated for 6 months at 30 C, and examined for swelling, toxicity, and recoverable C. botulinum. The minimal experimental sterilizing dose (ESD) based on nonswollen, nontoxic, but nonsterile end points was 2.5 < ESD 相似文献   

Radiation Sterilization of Prototype Military Foods: II. Cured Ham

Ten lots of diced cured ham, packed in cans, were inoculated with approximately 10(6)Clostridium botulinum spores per can. Each lot was seeded with a different strain (five type A and five type B strains). All cans were irradiated to various dose levels with Co(60). Evidence provided by swelling, toxicity, and recoverable C. botulinum with 6,350 cans demonstrated that: (i) 4.5 Mrad was more than adequate as a sterilization dose; (ii) the minimal experimental sterilizing dose (ESD) based on nonswollen nontoxic endpoints was 2.0 < ESD 相似文献   

Radiation Sterilization of Prototype Military Foods: Low-Temperature Irradiation of Codfish Cake, Corned Beef, and Pork Sausage

"Screening" packs comprising 10 lots each of codfish cake, corned beef, and pork sausage, each lot containing about 10(6) spores of a different strain (five type A and five type B) of Clostridium botulinum per can, were irradiated at -30 +/- 10 C with a series of increasing doses (20 replicate cans/dose) of (60)Co gamma rays. The cans were incubated for 3 months at 30 C and examined for swelling, toxin, and recoverable botulinal cells. Based on the latter criterion of spoilage, median lethal dose (LD(50)) and D values were estimated for each strain in each food. The most resistant strain in codfish cake, corned beef, and pork sausage was, respectively, 53B, 77A, and 41B. There was no clear-cut trend in the comparative order of resistance between the two antigenic types among the three foods. LD(50) values gave essentially the same order of resistances as the D values and may be used interchangeably with the latter for the 10 test organisms. "Clearance" packs consisting of the most resistant strain (about 10(7) spores/can) with its respective food were irradiated with a variety of doses at -30 +/- 10 C, using 100 replicate cans/dose (about 10(9) spores/dose). These packs were incubated for 6 months at 30 C and assayed for the three types of spoilage. Based on recoverable cells, the experimental sterilizing doses (ESD) for codfish cake, corned beef, and pork sausage were 2.5< ESD 相似文献   

Stability of Bacillus pumilus Spore Strips Used for Monitoring Radiation Sterilization

[This corrects the article on p. 999 in vol. 31.].     

Validation of Radiation Sterilization Dose for Lyophilized Amnion and Bone Grafts

A limited number of grafts produced in one batch is the main constrain to validate radiation sterilization dose of amnion and bone grafts according to ISO standard. The validation experiments done were according to ISO 13409 with a slight modification in sampling method. The experiments were carried out three times by using 20 samples each, 10 for bio-burden enumeration and 10 for sterility test at verification dose. The average bio-burden with sample item portion (SIP) = 1 for amnion membranes were 98, 50 and 69 cfu respectively and 0 cfu for bone grafts. Verification dose experiments, were done at doses of 2.90kGy for bone grafts and 5.13kGy for amnion grafts and the results of sterility tests showed that amnion grafts got one positive and bone grafts got 0 positive. The results met the requirements of ISO 13409 so that the radiation sterilization dose, at sterility assurance level of 10^-6 was 25kGy for both amnion and bone grafts. Viral contamination was excluded in this experiment.     

Microbiological Evaluation of Suture Items Before Radiation Sterilization

Microbiological contamination levels of suture samples taken at various stages of the manufacturing process in a new hygienically controlled plant were determined by employing a membrane filturation technique. Both raw material and materials handled manually in the production process were tested to assess the effect of manual handling on the product contamination level. Evaluation of the efficacy of contamination control, however, was directed primarily to the finished, packaged products, just prior to the processing with cobalt 60. The suture material for testing was divided into two groups, namely, wet and dry products, the wet being packaged in a special "tubing" fluid consisting mainly of isopropyl alcohol. Initial contamination results are reported as the average of values obtained on the test day and the preceding 9 consecutive production days. A total of 1,787 suture samples tested in the dry group showed daily averages varying between 2.1 and 14.8 contaminants per suture. The 2,980 wet-packaged suture samples tested gave daily averages varying from 0.7 to 4.2 contaminants per suture. The highest values obtained for an individual suture were 400 for the dry and 89 for the wet. Identification studies of the contaminants revealed that fungi predominated. Most of the bacterial contaminants proved to be spore-forming rods.     

Microbial Contamination on Disposable Hypodermic Syringes Prior to Sterilization by Ionizing Radiation

A large number of syringes were taken from the production lines of three independent manufacturers; the numbers and types of microorganisms contaminating these randomly sampled syringes were assessed in the laboratories maintained by each of these manufacturers for routine sterility testing, according to a standard protocol devised by the Research Committee of the UK Panel on Gamma and Electron Irradiation, which coordinated the investigation and analyzed the results. Items produced by a manufacturer were assessed for microbiological contamination both in their own laboratories and in the laboratories of the other manufacturers. The level of “false-positive” results was determined independently for each laboratory by the testing of “known sterile” items which had been subjected to the radiation-sterilization process. Both the percentage of syringes initially sterile and the average number of organisms per contaminated syringe differed among the three manufacturers. When corrected for interlaboratory differences, the number of syringes initially sterile ranged from 16 to 48%, and the mean number of organisms per contaminated syringe was 20 to 70. Of 964 syringes tested by all three laboratories, only one contained over 1,000 aerobic organisms (1,133). The most common organisms found were coagulase-negative, gram-positive cocci. Two manufacturers assessed contamination by anaerobic organisms; of 610 syringes, 1 contained 4,275 organisms and 3 more had 100 to 1,000 organisms, but 488 (80%) were uncontaminated by anaerobes. The results are discussed in the context of the choice of radiation dose necessary for the sterilization of medical products manufactured under controlled hygienic conditions.     

Radiation and Ethylene Oxide Terminal Sterilization Experiences with Drug Eluting Stent Products

Radiation and ethylene oxide terminal sterilization are the two most frequently used processes in the medical device industry to render product within the final sterile barrier package free from viable microorganisms. They are efficacious, safe, and efficient approaches to the manufacture of sterile product. Terminal sterilization is routinely applied to a wide variety of commodity healthcare products (drapes, gowns, etc.) and implantable medical devices (bare metal stents, heart valves, vessel closure devices, etc.) along with products used during implantation procedures (catheters, guidewires, etc.). Terminal sterilization is also routinely used for processing combination products where devices, drugs, and/or biologics are combined on a single product. High patient safety, robust standards, routine process controls, and low-cost manufacturing are appealing aspects of terminal sterilization. As the field of combination products continues to expand and evolve, opportunity exists to expand the application of terminal sterilization to new combination products. Material compatibility challenges must be overcome to realize these opportunities. This article introduces the reader to terminal sterilization concepts, technologies, and the related standards that span different industries (pharmaceutical, medical device, biopharmaceuticals, etc.) and provides guidance on the application of these technologies. Guidance and examples of the application of terminal sterilization are discussed using experiences with drug eluting stents and bioresorbable vascular restoration devices. The examples provide insight into selecting the sterilization method, developing the process around it, and finally qualifying/validating the product in preparation for regulatory approval and commercialization. Future activities, including new sterilization technologies, are briefly discussed.     

Radiation Sterilization: Microbiological Findings from Subprocess Dose Treatment of Disposable Plastic Syringes

S ummary : Disposable plastic hypodermic syringes were taken weekly from commercial production, immediately prior to radiation sterilization, at each of 3 firms. They were irradiated at doses less than that used for sterilization, either with electrons or gamma rays, and tested for sterility. The relationship between the dose applied and the resulting proportion of syringes positive was similar for each firm. Amongst the organisms surviving subnormal process doses was a yeast of unusually high radiation resistance. The possibility of establishing a microbiological quality control procedure based on the routine use of a subprocess dose technique is discussed.     

Studies on the Dose Requirement for the Radiation Sterilization of Medical Equipment. I. Influence of Suspending Media

S ummary : Spores of Bacillus pumilus were air dried from various suspending media on to the surfaces of different materials representative of those used for medical equipment currently being radiation-sterilized on a commercial scale. The resistance of the spores to gamma radiation was measured (inactivation factor of 10¹⁵ at 2·5 Mrads) and compared with that of the spores in liquid suspension under both aerated and anoxic conditions. Neither the nature of the medium nor that of the supporting surface affected radiation resistance except where local anoxic conditions might be expected, i.e. with spores suspended in a grease and with those trapped in a soluble film surface, when a twofold increase was observed.     

过氧化氢等离子体灭菌——高效的低温灭菌解决方案

过氧化氢等离子体灭菌做为一种高效的低温灭菌解决方案,具备安全、低温、高效、无毒等优越性。     

Heat Generation and its Impact on Lamp Fouling During Cheese Whey Sterilization using Ultraviolet Radiation

Summary In previous studies we found that lamp fouling was a major limitation when tubular ultraviolet reactors were used for sterilization of cheese whey over an extended period of time. Heat generation by ultraviolet lamps causes the temperature of the flowing fluid to rise and thus enhances fouling. In this study, the heat generated by a low pressure mercury ultraviolet lamp during continuous sterilization of cheese whey in three tubular reactors having different gap sizes (18, 13 and 6 mm) was calculated using a heat balance formula. The technique quantified the heat produced in and lost from each reactor. The heat balance calculations showed that lamp heat generation decreased with decreasing gap size (50.48, 47.71 and 31.91 kJ/h for 18, 13 and 6 mm gap sizes, respectively). However, the heat gain per unit volume and consequently the steady state temperature of the cheese whey effluent increased with decreasing gap size (91.79, 159.03 and 319.12 kJ/l and 44.5, 53.4 and 62.8 °C for 18, 13 and 6 mm gap sizes, respectively). A strong correlation between the amount of heat gain per unit volume and the amount of fouling material accumulated on the quartz surface was realized. The amount of accumulated fouling material increased with decreasing gap size (14.42, 15.31 and 25.26 g on wet basis for 18, 13 and 6 mm gap sizes, respectively). A new design in which the direct contact between the lamp and the flowing cheese whey is avoided and lamp cooling is introduced should be investigated.     

Paraformaldehyde for Surface Sterilization and Detoxification

Paraformaldehyde powder, depolymerized by heat, produced formaldehyde gas that was effective in sterilizing laboratory rooms, a mobile laboratory trailer, various surfaces, fiberglass filter medium, and specialized laboratory equipment. A sporulating and nonsporulating strain of bacteria, a virus, and a bacterial toxin were used as test agents. The dissemination procedures and equipment, the assay techniques, and the facilities and equipment sterilized were described.     

Fallopian Tube Surgery for Reversal of Sterilization

Of 16 consecutive cases of previous sterilization treated by tubal surgery fifteen women tested had patent Fallopian tubes. Over 18 months since operation there were four full-term pregnancies and two abortions among 11 patients. At interview with the patient it is important to emphasize that reconstruction of the tubes is a major operation and carries an increased subsequent hazard of ectopic pregnancy.     

Studies on the Dose Requirement for the Radiation Sterilization of Medical Equipment. II. A Comparison between Continuous and Fractionated Doses

S ummary : The lethal effect of gamma radiation on spores of Bacillus pumilus air dried on to a glass surface was measured by constructing dose-survivor curves. In one set of experiments the doses used were delivered without interruption, and in another set they were fractionated in various ways with storage intervals between fractions of up to one week. The data presented confirms the view that the efficiency of sterilization by irradiation would not be affected by interruption of dose delivery as might occur in plant operation. A situation where effects might be observed is discussed.