title: Sampling and Homogenization Strategies Significantly Influence the Detection of Foodborne Pathogens in Meat.
abstract: Efficient preparation of food samples, comprising sampling and homogenization, for microbiological testing is an essential, yet largely neglected, component of foodstuff control. Salmonella enterica spiked chicken breasts were used as a surface contamination model whereas salami and meat paste acted as models of inner-matrix contamination. A systematic comparison of different homogenization approaches, namely, stomaching, sonication, and milling by FastPrep-24 or SpeedMill, revealed that for surface contamination a broad range of sample pretreatment steps is applicable and loss of culturability due to the homogenization procedure is marginal. In contrast, for inner-matrix contamination long treatments up to 8 min are required and only FastPrep-24 as a large-volume milling device produced consistently good recovery rates. In addition, sampling of different regions of the spiked sausages showed that pathogens are not necessarily homogenously distributed throughout the entire matrix. Instead, in meat paste the core region contained considerably more pathogens compared to the rim, whereas in the salamis the distribution was more even with an increased concentration within the intermediate region of the sausages. Our results indicate that sampling and homogenization as integral parts of food microbiology and monitoring deserve more attention to further improve food safety.
authors.affiliation: Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany ; Department of Biology, Chemistry and Pharmacy, Free University Berlin, Takustraße 3, 14195 Berlin, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Rohde
authors.affiliation: Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany.
authors.forename: Jens Andre
authors.initials: JA
authors.lastname: Hammerl
authors.affiliation: Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Appel
authors.affiliation: Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Dieckmann
authors.affiliation: Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Al Dahouk
mesh_terms: D000818:Animals; D002645:Chickens / Q000382:microbiology*; D015169:Colony Count, Microbial; D005506:Food Contamination; D005516:Food Microbiology / Q000379:methods*; D059022:Food Safety; D008460:Meat / Q000382:microbiology*; D019779:Salmonella enterica / Q000302:isolation & purification* / Q000472:pathogenicity