Novel Continuous and Manual Sampling Methods for Beef Trim Microbiological Testing

Abstract

ABSTRACT A sampling method that represents a greater proportion of the beef trimmings in a 900-kg combo bin should improve the current pathogen sampling and detection programs used by fresh beef processors. This study compared two novel, nondestructive sampling methodologies (a continuous sampling device [CSD] and a manual sampling device [MSD]) with the current industry methodologies, the N60 Excision (the “gold standard”) and N60 Plus, for collection of trim samples. Depending on the experiment, samples were analyzed for naturally occurring Escherichia coli O157:H7 or Salmonella, inoculated surrogates, or indicator organisms in multiple plants, on multiple days, across multiple lean percentage mixtures. Experiments 1A and 1B with natural contamination found no E. coli O157:H7 but similar (P > 0.05) prevalence of Salmonella (CSD 9.2% versus N60 Excision 6.0%) and similar (P > 0.05) levels of indicator organisms for CSD compared with both N60 methodologies. In experiments 2 and 3, CSD cloth sampling had the same or higher prevalence of naturally occurring E. coli O157:H7 and E. coli O157:H7 surrogate organisms, as well as similar levels of indicator organisms compared with the N60 methodologies. In experiment 4, MSD cloth sampling detected similar (P > 0.05) prevalence of E. coli O157:H7 surrogate organisms, as well as slightly lower (P < 0.05) levels of indicator organisms compared with N60 Plus. In experiment 5, the MSD found similar (P > 0.05) prevalence of naturally occurring E. coli O157:H7 and the same or slightly higher (P < 0.05) levels of naturally occurring indicator organisms compared with N60 Plus. In experiment 6, the MSD detected the same (P > 0.05) prevalence of naturally occurring Salmonella as did N60 Excision. The results of these experiments collectively demonstrate that sampling beef trim using either the CSD or MSD provides organism recovery that is similar to or better than the N60 Excision or the N60 Plus methodologies.