Assessment of mould spoilage of packaging materials
Bactericidal activity of GAMA Healthcare Ltd. biocide determined using the European Standard Test method BS EN 1276:1997 against: Klebsiella pneumoniae NCTC 13368 (ATCC 700603) March 2007 Author: P. Humphreys Tests Carried Out By: University of Huddersfield Huddersfield Microbiology services School of Applied Sciences Queensgate Huddersfield HD1 3DH
Microbiological Tests
Test Method
British/European Standard BS EN 1276:1997. Dilution-neutralisation
Test Procedures
Full details of all the test and control procedures used are given in the Test Method
Disinfectant
GAMA Healthcare Ltd biocide as used in Clinell Universal Sanitising Wipes Batch number: N/A
Appearance product dilutions: colourless, clear product solution.
Interfering Substance (Organic Challenge)
0.3 g l-1 bovine albumin (final concentration)
3.0 g l-1 bovine albumin (final concentration)
Temperature
Contact Time Tested Test Organisms
Culture Medium
Incubation
Plates were incubated at 37 ºC for 24-48h
Neutraliser
Neutraliser, containing 60g/l Tween 80, 60g/l Saponin, 2g/l L-histidine, 2g/l L-cysteine in MRD.
General Method
A standard suspension of test organisms containing 1.5 – 5.0 x 108 cells ml-1 of bacteria was prepared. 1 ml of interfering substance was pipetted into a Universal bottle, followed by 1 ml of test organism suspension. The mixture was mixed and left for 2 minutes. After 2 minutes 8 ml of the Gama Health Care Ltd biocide was added. After a contact time of 5 minutes, a 1 ml sample of the reaction mixture was pipetted into 9 ml of neutraliser and left for 5 minutes. A 1 ml sample was then pipetted into 2 Petri dishes and mixed with 15 ml of culture medium tempered at 47 ºC. After setting, the Petri dishes were incubated at 37 ºC. Colony forming units were counted after 2-3 days incubation and the fraction of surviving organisms calculated.
Test Organism The test organism Klebsiella pneumoniae NCTC 13368 (ATCC 700603) is a multi-drug resistant strain which:
has intermediate resistance to ceftriaxone and gentamicin,
is used as a control organism for extended-spectrum beta-lactamase production and produces beta-lactamase SHV-18,
is resistant to ampicillin, aztreonam, cefoxitin, cefpodoxime, ceftazidime, chloramphenico, piperacillin and tetracycline.
Requirements of this standard The product, when tested as stipulated under simulated clean conditions (0.3 g l-1 bovine albumin) or dirty conditions (3 g l-1 bovine albumin) under the test conditions of ambient temperature (23 to 25 ºC), 5 minute contact, for Klebsiella pneumoniae NCTC 13368 shall demonstrate at least a 5 log10 reduction in viable counts. Results Results from the test are summarised in Tables 1 and 2, a full set of results can be found in Table 3. Test Conditions Contact Time (minutes) Log10 Reduction Achieved Table 1. Log10 reductions in Klebsiella pneumoniae NCTC 13368viable counts following a 5 minute exposure to the test material. Referenced Starting Final concentration Final concentration Organism concentration CFU ml-1clean 0.3 g l-1 CFU ml-1 dirty 3.0 g l-1 Bovine Albumin Bovine Albumin
viable count of bacterial colonies, 1 ml sample of 10
viable count of bacterial colonies, 1 ml sample of 10
Table 2. Reductions in Klebsiella pneumoniae NCTC 13368viable counts following a 5 minute exposure to the test material.
Interpretation of the Results When tested against Klebsiella pneumoniae NCTC 13368with a 5 minute contact time a full strength GAMA Healthcare Ltd biocide met the requirements of the Standard under simulated clean and dirty conditions. Conclusion According to EN 1276:1997, the batch provided of GAMA Healthcare biocide possesses bactericidal activity in 5 minutes at ambient temperature (23-25oC) under clean conditions (0.3g/l bovine albumin) and dirty conditions (3g/l bovine albumin) for referenced strain Klebsiella pneumoniae NCTC 13368. Dr Paul Humphreys School of Applied Sciences University of Huddersfield Appendix 1 VALIDATIONS Bacterial Test Test Procedure Results Bacterial Experimental Conditions Validation Neutraliser Dilution Neutralisation Control Organism Suspension Suspension Clean Dirty Toxicity Control Clean Dirty Verification of Methodology Passed Log10 Reductions/cfu/ml
N is between 1.5E+8 cfu/ml and 5E+8 cfu/ml, N =
Nv is between 6E+2 cfu/ml and 3E+3 cfu/ml, Nv =
Table 3. Testing of Klebsiella pneumoniae NCTC 13368 the GAMA Healthcare Ltd biocide using BS EN 1276:1997.
scored and the calculated dosage should beprovided to the nearest half tablet increment. Vetmedin® Contraindications: Vetmedin should not be given in cases of hypertrophic cardiomyopathy, aorticstenosis, or any other clinical condition where an Caution: Federal law restricts this drug to use by augmentation of cardiac output is inappropriateor on the order of a licensed veterinarian.
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