title: A possible approach to assess acidification of meat starter cultures: a case study from some wild strains of Lactobacillus plantarum.
abstract: BACKGROUND
  The performances of four autochthonous isolates of Lactobacillus plantarum were assessed to study the most important variables acting on acidification and to propose a possible step-by-step approach for the validation at laboratory scale. This main topic was addressed through three intermediate steps: (1) evaluation of acidification in liquid and solid media, as a function of salt, nitrites, nitrates, lactose, pepper and temperature; (2) assessing acidification in a pork-meat preparation; and (3) designing a protocol to improve the performances at sub-optimal temperatures. The concentration of the ingredients and the temperature were combined through a 3k-pFractional Factorial Design. Acidification and viable count were assessed and modelled through a multi-factorial ANOVA.
  
  
  RESULTS
  In model systems acidification was affected by lactose and was maximum (ΔpH of ca. 2.8-3.0) in the combinations containing 0.4% lactose, 250 mg kg-1nitrates or 150 mg kg-1nitrites, 5% salt, and at 30 °C. Solid media caused a higher acidification. In the pork meat preparation, the effect of salt and nitrites was significant. At 10 °C the strains could not reduce pH, but this ability could be induced using an adaptation step.
  
  
  CONCLUSIONS
  Acidification was affected by lactose in the model system, whereas in meat preparation the other variables were significant. In addition, a protocol to improve acidification at 10 °C was optimised. © 2016 Society of Chemical Industry.
authors.affiliation: Department of the Science of Agriculture, Food and Environment, University of Foggia, 71122, Via Napoli 25, Foggia, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Speranza
authors.affiliation: Department of the Science of Agriculture, Food and Environment, University of Foggia, 71122, Via Napoli 25, Foggia, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Bevilacqua
authors.affiliation: Department of the Science of Agriculture, Food and Environment, University of Foggia, 71122, Via Napoli 25, Foggia, Italy.
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Corbo
authors.affiliation: Department of the Science of Agriculture, Food and Environment, University of Foggia, 71122, Via Napoli 25, Foggia, Italy.
authors.forename: Milena
authors.initials: M
authors.lastname: Sinigaglia
mesh_terms: D000818:Animals; D005285:Fermentation; D005511:Food Handling / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D048191:Lactiplantibacillus plantarum / Q000378:metabolism*; D008461:Meat Products / Q000032:analysis* / Q000382:microbiology*; D013552:Swine
keywords: Lactobacillus plantarum; acidification; autochthonous; sausage; starter selection