title: Quantifying Effect of Lactic, Acetic, and Propionic Acids on Growth of Molds Isolated from Spoiled Bakery Products.
abstract: The combined effect of undissociated lactic acid (0 to 180 mmol/liter), acetic acid (0 to 60 mmol/liter), and propionic acid (0 to 12 mmol/liter) on growth of the molds Aspergillus niger, Penicillium corylophilum, and Eurotium repens was quantified at pH 3.8 and 25°C on malt extract agar acid medium. The impact of these acids on lag time for growth (λ) was quantified through a gamma model based on the MIC. The impact of these acids on radial growth rate (μ) was analyzed statistically through polynomial regression. Concerning λ, propionic acid exhibited a stronger inhibitory effect (MIC of 8 to 20 mmol/liter depending on the mold species) than did acetic acid (MIC of 23 to 72 mmol/liter). The lactic acid effect was null on E. repens and inhibitory on A. niger and P. corylophilum. These results were validated using independent sets of data for the three acids at pH 3.8 but for only acetic and propionic acids at pH 4.5. Concerning μ, the effect of acetic and propionic acids was slightly inhibitory for A. niger and P. corylophilum but was not significant for E. repens. In contrast, lactic acid promoted radial growth of all three molds. The gamma terms developed here for these acids will be incorporated in a predictive model for temperature, water activity, and acid. More generally, results for μ and λ will be used to identify and evaluate solutions for controlling bakery product spoilage.
authors: L'Université Nantes Angers Le Mans, Oniris, Nantes F-44322 cedex 3, France.
authors: Stéphane
authors: S
authors: Dagnas
authors: L'Université Nantes Angers Le Mans, Oniris, Nantes F-44322 cedex 3, France.
authors: Emilie
authors: E
authors: Gauvry
authors: L'Université Nantes Angers Le Mans, Oniris, Nantes F-44322 cedex 3, France.
authors: Bernard
authors: B
authors: Onno
authors: L'Université Nantes Angers Le Mans, Oniris, Nantes F-44322 cedex 3, France; Institut National de la Recherche Agronomique, UMR1014 Sécurité des Aliments et Microbiologie, Nantes F-44307, France. jeanne-marie.membre@oniris-nantes.fr.
authors: Jeanne-Marie
authors: JM
authors: Membré
mesh_terms: D019342:Acetic Acid / Q000494:pharmacology*; D001234:Aspergillus niger / Q000187:drug effects / Q000302:isolation & purification; D055325:Eurotium / Q000187:drug effects / Q000302:isolation & purification; D005506:Food Contamination / Q000517:prevention & control*; D005511:Food Handling; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D010407:Penicillium / Q000187:drug effects / Q000302:isolation & purification; D011422:Propionates / Q000494:pharmacology*; D013172:Spores, Fungal / Q000187:drug effects / Q000302:isolation & purification; D013696:Temperature
chemical_list: D011422:Propionates; D019344:Lactic Acid; C029658:propionic acid; D019342:Acetic Acid