Keywords
reference material
food microbiology
How to Cite
Abstract
Proficiency tests are considered relevant tools of quality control programs used to monitor the laboratory performance and to assess the reliability of tests results. In Brazil, the provision of proficiency testing (PT) is restricted to food microbiology area. Furthermore, high costs reduce the regular participation of national laboratories in these tests. This study evaluated the freeze-drying technique employed for preparing reference materials (RM) to be used in the PT schemes for detecting Salmonella spp. in milk. The concentration of inoculums used for preparing two batches of RM was determined, and the procedures for matrix contamination were standardized. The control trials were established in order to monitor the quality of the produced RM, and among them, there are long and short-term homogeneity and stability assays. The freeze-drying technique proved to be a suitable procedure for producing RM for PT. The RM were stable for the first three months when stored at -20ºC, nevertheless, viability loss could be observed after 12-month storage. The RM were stable at 4°C at short-term stability, although when the products were kept at 25°C and 37°C for seven days, a significant reduction in the number of cells could be observed.References
1. Hayes D. Quality assurance in the microbiology laboratory. Accredit Qual Assur. 1996; 1: 18-23.
2. Roberts D. Proficiency testing in the food microbiology laboratory. Arh Hig Rada Toksikol J. 1999; 50(1): 55-65.
3. Camargo, TSP. Proposta de Integração das Normas ISO/IEC 17025 e BPL a um Software de Gerenciamento e Controle Laboratorial. [monografia de graduação]. Minas Gerais: Universidade Federal de Itajubá, 2006.
4. NBR ISO/IEC 17025. Requisitos gerais para a competência de laboratórios de ensaio e calibração. Rio de Janeiro: ABNT, 2005. 31p.
5. Rosengren A, Heneryd AC. Proficiency testing schemes – their role in quality assurance. Int J Food Microbiol. 1998; 45: 55.
6. Emons H, Fajgelj A, Van der Veen AMH, Watters R. New definitions on reference materials. Accredit Qual Assur. 2006; 10: 576-8.
7. NBR ISO/GUIA 30. Termos e definições relacionados com materiais de referência. Rio de Janeiro: ABNT, 2000.
8. Philipp WJ, Iwaarden PV, Schimmel H, Meeus N, Kollmorgen N. Development of reference materials for microbiological analysis. Accredit Qual Assur. 2007; 12: 134-8.
9. Janning B, Veld PHI, Mooijman KA, Havelaar AH. Development, production and certification of microbiological reference materials. Fresenius J Anal Chem. 1995; 352: 240-5.
10. Thompson M, Ellison SLR, Wood R. International harmonized protocol for proficiency testing of (chemical) analytical chemistry laboratories. Pure Appl Chem. 2006; 78(1): 145-96.
11. International Organization for Standardization – ISO GUIDE 35. Reference Materials – General and statistical principles for certification. 2006.
12. NBR ISO/IEC GUIA 43-1. Ensaios de proficiência por comparações interlaboratoriais - Parte 1 - Desenvolvimento e operação de programas de ensaios de proficiência. Rio de Janeiro: ABNT, 1999.
13. ILAC-G 13:08/2007. Guidelines for the requirements for the competence of providers of proficiency testing schemes. ILAC, 2007.
14. International Organization for Standardization – ISO 13528. Statistical methods for use in proficiency testing by interlaboratory comparisons. 2005.
15. Instituto Nacional de Controle de Qualidade em Saúde (INCQS). Oficina Sobre Ensaios de Proficiência e Produção de Materiais de Referência no Brasil, II. Rio de Janeiro 15 a 16 de abril de 2008. Relatório. Rio de Janeiro: INCQS/FIOCRUZ, 2008.
16. Determinação de Umidade Residual por Gravimetria em Vacinas Liofilizadas. Rev. 03. In: Manual da Qualidade. Rio de Janeiro: INCQS/FIOCRUZ, 2008. Seção 4.3. 5p. (65.3130.001).
17. Food and Drug Administration – FDA, Guideline for the Determination of Residual Moisture in Dried Biological Products. 1990. [Acesso em 17 Nov. 2008.]. Disponível em: [http://www.fda.gov/Cber/gdlns/moisture.htm].
18. Produção e Preservação pelo Método de Liofilização de Bactérias da Coleção de Culturas. Rev. 03. In: Manual da Qualidade. Rio de Janeiro: INCQS/FIOCRUZ, 2005. Seção 10. 14p. (65.3230.001).
19. Schulten SM, in Veld PH, Ghameshlou Z, Schimmel H, Linsinger T. The certification of the number of colony forming particles of Salmonella Typhimurium and number fraction of negative capsules from artificially contaminated milk powder – CRM 507 R. European Comission, bcr information, 2000.
20. Fearn T, Thompson M. A new test for “sufficient homogeneity”. Analyst. 2001; 126: 1414-7.
21. Lamberty A, Schimmel H, Pauwels J. The study of the stability of reference materials by isochronous measurements. Fresenius J Anal Chem. 1998; 360: 359–61.
22. Barros NB, Scarminio IS, Bruns RE. Como Fazer Experimentos – Pesquisa e Desenvolvimento na Ciência e na Indústria, 2 ed. Campinas, SP: Editora Unicamp, 2003.
23. Peterz M, Norberg P. Freeze dried mixed cultures as samples for proficiency tests and collaborative studies in food microbiology. J Assoc Anal Chem. 1983; 66(6): 1510-3.
24. Beckers HJ, Van Lesden FM, Meijssen MJM, Kampelmacher EH. Reference material for the evaluation of a standard method for the detection of Salmonella in food and feeding stuffs. J Appl Bacteriol. 1985; 59: 507-12.
25. In’t Veld, PH. The use of reference materials in quality assurance programmes in food microbiology laboratories. Int J Food Microbiol. 1998; 45(1): 35-41.
26. In’t Veld PH, Havelaar AH, Van Strijp-Lockefeer NGWM. The certification of a reference material for the evaluation of methods for the enumeration of Bacillus cereus. J Appl Bacteriol. 1999; 86: 266-74.
27.Bricio SML. Avaliação da Qualidade Microbiológica de Salpicão de Frango e Salada de Maionese com Ovos Servidos em Restaurantes Self-service da Cidade do Rio de Janeiro. [tese de doutorado]. Rio de Janeiro: Universidade Federal do Rio de Janeiro, 2004.
28. Nunes FFV. Limite Mínimo de Detecção de Métodos de Análise de Salmonella spp. para Alimentos: Uma Contribuição Metodológica. [dissertação de mestrado]. Recife: Universidade Federal de Pernambuco, 2006.
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