title: Enhancement of microbiological safety levels of aseptically admixed total parenteral nutrition solutions through low-dose gamma irradiation.
abstract: This study was undertaken to determine the effect of low-dose gamma irradiation on aseptically admixed total parenteral nutrition (TPN) solutions to which large inocula of three test bacterial species were added. Microbiological safety levels were quantified in terms of sterility assurance levels (SALs), indicating the probability of contamination occurring expressed as 10-n. The radiation sensitivity (D10 values) of test bacteria in TPN solutions inoculated with a series of bacteria recognized as common contaminants of these products, was determined. Attainable SALs of TPN solutions containing test bacteria were subsequently calculated from the D10 values. Results showed that a minimum absorbed radiation dose as low as 1.5 kGy improved the SAL of aseptically prepared TPN solutions from a probability value of 10(-3) to a value of less than 10(-8) for the microorganisms investigated. At an absorbed dose as high as 8.3 kGy, no measurable changes in amino acid, electrolyte, glucose and lipid components of the solutions were detected. These findings have important implications for the enhancement of microbiological safety levels of aseptically prepared intravenous fluids in general.
authors.affiliation: Department of Medical Microbiology, South African Institute for Medical Research, Johannesburg.
authors.forename: H J
authors.initials: HJ
authors.lastname: Koornhof
authors.forename: M
authors.initials: M
authors.lastname: Isaäcson
authors.forename: J
authors.initials: J
authors.lastname: Saunders
authors.forename: C J
authors.initials: CJ
authors.lastname: van Wyk
authors.forename: A F
authors.initials: AF
authors.lastname: Kotzé
authors.forename: I C
authors.initials: IC
authors.lastname: Rosekilly
authors.forename: T A
authors.initials: TA
authors.lastname: du Plessis
mesh_terms: D000596:Amino Acids / Q000378:metabolism / Q000528:radiation effects; D015169:Colony Count, Microbial; D004355:Drug Stability; D004573:Electrolytes / Q000378:metabolism / Q000528:radiation effects; D016972:Enterobacter cloacae / Q000528:radiation effects; D005527:Food, Fortified / Q000382:microbiology* / Q000528:radiation effects; D005720:Gamma Rays; D005947:Glucose / Q000378:metabolism / Q000528:radiation effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007711:Klebsiella pneumoniae / Q000528:radiation effects; D050356:Lipid Metabolism; D008055:Lipids / Q000528:radiation effects; D010289:Parenteral Nutrition, Total / Q000592:standards*; D012705:Serratia / Q000528:radiation effects; D012996:Solutions; D013242:Sterilization
chemical_list: D000596:Amino Acids; D004573:Electrolytes; D008055:Lipids; D012996:Solutions; D005947:Glucose