Salmonella spp. Isolated by Miniaturized Most Probable Number and Conventional Microbiology in Poultry Slaughterhouses
Keywords:Salmonella, mMPN, serovars, poultry slaughterhouses.
Background: Salmonella spp. are frequently isolated from fowls, and their detection in poultry products varies according to the breeding system and the slaughtering process, bringing risks to the consumer and compromising the marketability. The control of Salmonella in poultry slaughterhouses is based on the detection of bacteria, but the quantification of the agent would be important in assessing risk, as well as in obtaining data to determine the capacity of each step of the process to decrease or increase bacterial contamination. The aims of this study were to propose a method for the quantification of Salmonella in poultry slaughterhouses, frequency of isolation and serovars identified.
Materials, Methods & Results: Twenty-one broiler flocks from seven federally inspected slaughterhouses in southern Brazil, totaling 1,071 samples, were assessed by miniaturized most probable number (mMPN) and conventional microbiology. The samples were collected in triplicate at 17 points, which included cloacae, transportation cages before and after sanitization, water (scald tank, supply, pre-chiller and chiller), and carcasses (before and after scalding, defeathering, rinsing, evisceration, final rinsing, chilling at 4ºC, and freezing at -12°C for 24 h, 30 and 60 days). Typical Salmonella colonies were submitted to TSI, LIA, SIM, urea, and polyvalent anti-O antiserum tests, and to final identification by Microarray by Check&Trace. Nine of the 1,071 (0.83%) samples analyzed by mMPN and by conventional microbiology were positive for Salmonella and the following serovars were identified: Anatum, Brandenburg, Agona, Tennessee, Bredeney, Schwarzengrund and Infantis.
Discussion: This positive rate was lower than that described by other authors, whose rates ranged from 3% and 39% for the isolation of Salmonella spp. from different sources, such as slaughterhouses and retail sales in samples collected in Brazil. The low frequency of isolation of Salmonella in this study can be attributed to the efficiency of control systems used from the field to the slaughterhouse, such as Good Manufacturing Practices (GMP) and Sanitation Standard Operating Procedures (SSOP), which are HACCP requirements. Also, when slaughtering technology actions are properly managed, such as water replacement and temperatures lower than 4ºC in the chiller, the initial contamination by Salmonella spp. can be reduced, with a decline in contamination from 70% to 20%, and with a reduction in the contamination of broiler carcasses after chilling from 15.8% to 3.3%. On the other hand the contamination of carcasses by Salmonella before pre-chilling and in post-chilling might be due to the automated system, inadequate temperatures during chilling, and inappropriate water chlorination in the assessed meat-packing plant. Of the 17 points evaluated, seven were positive for Salmonella, especially the cages after sanitization and frozen carcasses. The contamination by Salmonella spp. in transportation cages after sanitization indicates inefficiency of the automated system as well as possible bacterial resistance to the sanitizers used in SSOP while the isolation in carcasses frozen for 24 h and 60 days demonstrates the thermal resistance of the bacterium to a conservation method widely used in the food industry. In this work, just one of the nine positive samples for Salmonella was identified by conventional methods (CM) and mMPN. The discrepancy between methods can be explained by the heterogeneous distribution of Salmonella and other bacteria in naturally contaminated samples. Samples that were positive in the qualitative test but negative in the mMPN protocol could have had a number of Salmonella below the detection amount.
Baggensen D.L., Bagger J., Mogelmose V., Nielsen B., Svensmark B. & Olsen J.E. 2001. Quantification of DT104 in slurry from infected pigs. In: 6th Workshop organized by CRL - Salmonella. (Bilthoven, Belgium). June 11-12, Report 284500019/2001. (5): 30-32.
Borsoi A., Moraes H.L.S., Salle C.T.P. & Nascimento V.P. 2010. Número mais provável de Salmonella isoladas de carcaças de frango resfriadas. Ciência Rural. 40(11): 2338-2342.
Brasil. 2003. Ministério da Agricultura, Pecuária e Abastecimento - MAPA / Secretaria de Defesa Agropecuária. Programa de Redução de Patógenos Monitoramento Microbiológico e Controle de Salmonella sp. em Carcaças de Frangos e Perus. Diário Oficial da União. Brasília, Instrução Normativa nº 70, de 06 de outubro de 2003. Seção 1. pp.9-10.
Colla F.L., Rodrigues L.B., Borsoi A., Dickel E.L., Nascimento V.P. & Santos L.R. 2012. Isolamento de Salmonella Heidelberg em diferentes pontos da tecnologia de abate de frangos de corte. Arquivos do Instituto Biológico. 79(4): 603-606.
Colla F.L., Mion L., Parizotto L., Rodrigues L.B., Pilotto F., Dickel E.L., Nascimento V.P. & Santos L.R. 2014. Miniaturized most probable number for the enumeration of Salmonella sp in artificially contaminated chicken meat. Brazilian Journal of Poultry Science. 16(1): 45-48.
Dickel E.L., Santos L.R., Rodrigues L.B., Valle S.F. & Cecatti D. 2005. Ocorrência de Salmonella em abatedouros de aves com tecnologia totalmente automatizada (grande porte), semi automatizada (médio porte) e semi automatizada (pequeno porte). Higiene Alimentar. 19(131): 62-67.
Duarte D.A.M., Ribeiro A.R., Vasconcelos A.M.M., Santos S.B., Silva J.V.D., Andrade P.L.A. & Falcão L. 2009. Occurrence of Samonella spp. in broiler chicken carcasses and their susceptibility to antimicrobial agents. Brazilian Journal of Microbiology. 40(3): 569-573.
Fravalo P., Hascoet Y., Le Fellic M., Quegumer S., Petton J. & Salvat G. 2003. Convenient method for rapid and quantitative assessment of Salmonella enteric contamination: the mini-MSRV MPN technique. Journal of Rapid Methods and Automation in Microbiology. 11(2): 81-88.
Gast R., Guraya R. & Guard-Bouldin J. 2007. Colonization of specific regions of the reproductive tract and deposition at different locations inside eggs laid by hens infected with Salmonella Enteritidis or Salmonella Heidelberg. Avian Diseases. 51(1): 40-44.
International Organization for Standardization. 2002. ISO 6579:2002. Microbiology of Food and Animal Feeding Stuffs – Horizontal Method for the Detection of Salmonella spp. Geneva, Switzerland: International Standards Organization. 27p.
Lopes M., Galhardo J.A., Oliveira J.T., Tamanini R., Sanches S.F. & Muller E.E. 2007. Pesquisa de Salmonella spp. e microrganismos indicadores em carcaças de frango e água de tanques de pré-resfriamento em abatedouro de aves. Semina. Universidade Estadual de Londrina. 28(3): 465-476.
Moreira G.N., Rezende C.S.M., Carvalho R.N., Mesquita S.Q.P., Oliveira N.A. & Arruda M.L.T. 2009. Ocorrência de Salmonella sp. em carcaças de frangos abatidos e comercializados em municípios do estado de Goiás. Revista Instituto Adolfo Lutz. 67(2): 126-130.
Pavic A., Groves P.J., Bailey G. & Cox J.M. 2010. A validated miniaturized MPN method, based on ISO 6579:2002, for the enumeration of Salmonella from poultry matrices. Journal of Applied Microbiology. 109(1): 25-34.
Ribeiro A.R., Kellermann A., Santos L.R., Bessa M.C. & Nascimento V.P. 2007. Salmonella spp. in raw broiler parts: occurrence, antimicrobial resistance profile and phage typing of the Salmonella Enteritidis isolates. Brazilian Journal of Microbiology. 38(2): 296-299.
Santos D.M.S., Berchieri Jr.A., Fernandes S.A., Tavechio A.T. & Amaral L.A. 2000. Salmonella em carcaças de frango congeladas. Pesquisa Veterinária Brasileira. 20(1): 39-42.
Silva N.A., Junqueira V., Silveira N.F.A., Taniwaki M.H., Santos R.F.S. & Gomes R.A.R. 2010. Manual de métodos de análise microbiológica de alimentos e água. São Paulo: Livraria Varela, 624p.
Skovgaard N. 2005. Current topics in food microbiology. International Journal of Food Microbiology. 99: 107-111.
United States Department of Agriculture (USDA). 2013. Progress report on Salmonella and Campylobacter testing of raw meat and poultry products, 1998-2012. [Fonte: <http://www.fsis.usda.gov/wps/wcm/connect/8d792eef_ f44d_4ccb_8e25_ef5bdb4c1dc8/47>]. [Accessed September 2015].
World Health Organization (WHO). 2013. Global Foodborne Infections Network (GFN) Country Databank. [Fonte:< http://thor.dfvf.dk/pls/portal/GSS.YEAR_RANK_REP.show_parms.>]. [Accessed September 2015].
How to Cite
This journal provides open access to all of its content on the principle that making research freely available to the public supports a greater global exchange of knowledge. Such access is associated with increased readership and increased citation of an author's work. For more information on this approach, see the Public Knowledge Project and Directory of Open Access Journals.
We define open access journals as journals that use a funding model that does not charge readers or their institutions for access. From the BOAI definition of "open access" we take the right of users to "read, download, copy, distribute, print, search, or link to the full texts of these articles" as mandatory for a journal to be included in the directory.
La Red y Portal Iberoamericano de Revistas Científicas de Veterinaria de Libre Acceso reúne a las principales publicaciones científicas editadas en España, Portugal, Latino América y otros países del ámbito latino