Microbiological Decontamination of Poultry Feed—Evaluation of Steam Conditioners

The microbial decontamination of chicken feed, obtained from a commercial pellet mill, was evaluated using a direct-fired steam conditioner (DFSC; APC System™). The standard plate count of the feeds before (mash) and after (pellets) conditioning ranged from 65×104 to 83×105 colony forming units (CFU) g−1 and from 91×101 to 92×103 CFU g−1, respectively. The incidence of Escherichia coli,SalmonellaandListeriain the feeds before conditioning was 61·7, 8·3 and 27·1%, respectively. Following conditioning these levels were reduced to 1·7, 1·7 and 0%, respectively. Species ofListeriaandSalmonellaidentified includedL monocytogenes,L innocuaandS agona,S ohio,S heidelberg,S senftenberg,S tallahasseandS braenderup, respectively. Compared with a conventional, indirect-fired boiler-generated-steam conditioner (IFSC) the direct-fired steam conditioner proved superior in regards to pathogen decontamination; noE coli,SalmonellaorListeriawere recovered from mash lots positive for these microorganisms. However, with the IFSC system, bothE coliandL monocytogenswere recovered at levels of 11·1 and 5·6%, respectively.