title: Use of Enterococcus faecium as a surrogate for Salmonella enterica during extrusion of a balanced carbohydrate-protein meal.
abstract: Multiple outbreaks of salmonellosis have been associated with the consumption of low-moisture products, including extruded products. Therefore, there is a need for a nonpathogenic, surrogate microorganism that can be used to validate extrusion processes for Salmonella. The objective of this research was to determine if Enterococcus faecium NRRL B-2354 is an adequate surrogate organism for Salmonella during extrusion. Extrusions at different temperatures were done in material contaminated with both organisms. Results indicated that the minimum temperature needed to achieve a 5-log reduction of E. faecium was 73.7°C. Above 80.3°C, the enumeration of E. faecium showed counts below the detectable levels (<10 CFU g(- 1)). Salmonella was reduced by 5 log at 60.6°C, and above 68.0°C the levels of this organism in the product were below the detection limit of the method. The data show that E. faecium is inactivated at higher temperatures than Salmonella, indicating that its use as a surrogate would provide an appropriate margin of error in extrusion processes designed to eliminate this pathogen. Attempting to minimize risk, the industry could validate different formulations, in combination with thermal treatments, using E. faecium as a safer alternative for those validation studies.
authors.affiliation: The Food Processing Center, University of Nebraska, Lincoln, Nebraska 68583, USA; Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska 68583, USA.
authors.forename: Andreia
authors.initials: A
authors.lastname: Bianchini
authors.affiliation: The Food Processing Center, University of Nebraska, Lincoln, Nebraska 68583, USA; Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska 68583, USA.
authors.forename: Jayne
authors.initials: J
authors.lastname: Stratton
authors.affiliation: The Food Processing Center, University of Nebraska, Lincoln, Nebraska 68583, USA.
authors.forename: Steve
authors.initials: S
authors.lastname: Weier
authors.affiliation: Wenger Manufacturing, Inc., 714 Main Street, Sabetha, Kansas 66534, USA.
authors.forename: Timothy
authors.initials: T
authors.lastname: Hartter
authors.affiliation: Wenger Manufacturing, Inc., 714 Main Street, Sabetha, Kansas 66534, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Plattner
authors.affiliation: Wenger Manufacturing, Inc., 714 Main Street, Sabetha, Kansas 66534, USA.
authors.forename: Galen
authors.initials: G
authors.lastname: Rokey
authors.affiliation: Wenger Manufacturing, Inc., 714 Main Street, Sabetha, Kansas 66534, USA.
authors.forename: Gerry
authors.initials: G
authors.lastname: Hertzel
authors.affiliation: Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska 68583, USA.
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Gompa
authors.affiliation: Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska 68583, USA.
authors.forename: Bismarck
authors.initials: B
authors.lastname: Martinez
authors.affiliation: Department of Statistics, University of Nebraska, Lincoln, Nebraska 68583, USA.
authors.forename: Kent M
authors.initials: KM
authors.lastname: Eskridge
mesh_terms: D015169:Colony Count, Microbial; D016984:Enterococcus faecium / Q000254:growth & development*; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D019779:Salmonella enterica / Q000254:growth & development*; D013696:Temperature; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water