title: Microbial successions are associated with changes in chemical profiles of a model refrigerated fresh pork sausage during an 80-day shelf life study.
abstract: Fresh pork sausage is produced without a microbial kill step and therefore chilled or frozen to control microbial growth. In this report, the microbiota in a chilled fresh pork sausage model produced with or without an antimicrobial combination of sodium lactate and sodium diacetate was studied using a combination of traditional microbiological methods and deep pyrosequencing of 16S rRNA gene amplicons. In the untreated system, microbial populations rose from 10(2) to 10(6) CFU/g within 15 days of storage at 4°C, peaking at nearly 10(8) CFU/g by day 30. Pyrosequencing revealed a complex community at day 0, with taxa belonging to the Bacilli, Gammaproteobacteria, Betaproteobacteria, Actinobacteria, Bacteroidetes, and Clostridia. During storage at 4°C, the untreated system displayed a complex succession, with species of Weissella and Leuconostoc that dominate the product at day 0 being displaced by species of Pseudomonas (P. lini and P. psychrophila) within 15 days. By day 30, a second wave of taxa (Lactobacillus graminis, Carnobacterium divergens, Buttiauxella brennerae, Yersinia mollaretti, and a taxon of Serratia) dominated the population, and this succession coincided with significant chemical changes in the matrix. Treatment with lactate-diacetate altered the dynamics dramatically, yielding a monophasic growth curve of a single species of Lactobacillus (L. graminis), followed by a uniform selective die-off of the majority of species in the population. Of the six species of Lactobacillus that were routinely detected, L. graminis became the dominant member in all samples, and its origins were traced to the spice blend used in the formulation.
authors.affiliation: Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, USA abenson1@unl.edu.
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Benson
authors.affiliation: ConAgra Foods, Inc., Omaha, Nebraska, USA.
authors.forename: Jairus R D
authors.initials: JR
authors.lastname: David
authors.affiliation: ConAgra Foods, Inc., Omaha, Nebraska, USA.
authors.forename: Stefanie Evans
authors.initials: SE
authors.lastname: Gilbreth
authors.affiliation: ConAgra Foods, Inc., Omaha, Nebraska, USA.
authors.forename: Gordon
authors.initials: G
authors.lastname: Smith
authors.affiliation: Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Nietfeldt
authors.affiliation: Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Legge
authors.affiliation: Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, USA.
authors.forename: Jaehyoung
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, USA.
authors.forename: Rohita
authors.initials: R
authors.lastname: Sinha
authors.affiliation: ConAgra Foods, Inc., Omaha, Nebraska, USA.
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Duncan
authors.affiliation: Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, USA.
authors.forename: Junjie
authors.initials: J
authors.lastname: Ma
authors.affiliation: ConAgra Foods, Inc., Omaha, Nebraska, USA.
authors.forename: Indarpal
authors.initials: I
authors.lastname: Singh
mesh_terms: D000890:Anti-Infective Agents / Q000378:metabolism; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D058448:Biota; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005520:Food Preservatives / Q000378:metabolism; D061353:Food Storage; D007773:Lactates / Q000378:metabolism; D008461:Meat Products / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012034:Refrigeration; D017422:Sequence Analysis, DNA; D013696:Temperature
chemical_list: D000890:Anti-Infective Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005520:Food Preservatives; D007773:Lactates; D012336:RNA, Ribosomal, 16S