INTERACTIONS BETWEEN pH AND MALIC ACID CONCENTRATION ON THE INACTIVATION OF LISTERIA MONOCYTOGENES

The effects and interactions of malic acid concentration and pH on the inactivation kinetics of a three strain mixture of Listeria monocytogenes was studied in brain heart infusion broth (BHI). The medium was supplemented with malic acid and monosodium malate to achieve pH levels of 3.0, 3.5, 4.0, 4.5, 5. 0, 5.5, 6. 0, 6.5 or 7.0 in conjunction with concentrations of 0.0, 0.1, 0. 5, 1.0 and 2. 0 M. Duplicate 20-mL portions of each pH/malate level were inoculated (ca. 10 8 cfu/mL), stored aerobically at 28C, and assayed periodically for viable counts by plating on BHI agar. Survivor curves were generated by fitting data to a linear model that includes a lag term and used to calculate D-values and times to 4-D inactivation . Inactivation rates were dependent on both the pH and malic acid concentration. At the higher pH levels, malic acid appeared to provide some degree of protection compared to control cultures where the pH was adjusted with HCl. At lower pH values and at higher malic acid concentrations, a concentration-dependent anion effect was observed. The results indicate that malic acid is a relatively benign organic acid. Its antimicrobial characteristics are similar to those of citric acid and is substantially less bactericidal than lactic or acetic acids.

[1]  R. Buchanan,et al.  Expanded models for the non‐thermal inactivation of Listeria monocytogenes , 1997, Journal of applied microbiology.

[2]  R. Buchanan,et al.  Culturing enterohemorrhagic Escherichia coli in the presence and absence of glucose as a simple means of evaluating the acid tolerance of stationary-phase cells , 1996, Applied and environmental microbiology.

[3]  L. Shelef,et al.  Metabolic activities of Listeria monocytogenes in the presence of sodium propionate, acetate, lactate and citrate. , 1996, The Journal of applied bacteriology.

[4]  G. Leyer,et al.  Acid adaptation of Escherichia coli O157:H7 increases survival in acidic foods , 1995, Applied and environmental microbiology.

[5]  J. Luchansky,et al.  Effects of Acid Type and Alta™2341 on Listeria monocytogenes in a Queso Blanco Type of Cheese. , 1995, Journal of food protection.

[6]  Robert L. Buchanan,et al.  Model for the non-thermal inactivation of Listeria monocytogenes in a reduced oxygen environment , 1995 .

[7]  D. Conner,et al.  Growth and survival of Escherichia coli O157:H7 under acidic conditions , 1995, Applied and environmental microbiology.

[8]  Robert L. Buchanan,et al.  Interaction of Citric Acid Concentration and pH on the Kinetics of Listeria monocytogenes Inactivation. , 1994, Journal of food protection.

[9]  C. Kaspar,et al.  Escherichia coli O157: H7 Acid Tolerance and Survival in Apple Cider. , 1994, Journal of food protection.

[10]  J. Slonczewski,et al.  Acid and base resistance in Escherichia coli and Shigella flexneri: role of rpoS and growth pH , 1994, Journal of bacteriology.

[11]  R. C. Whiting,et al.  Non‐Thermal Inactivation Models for Listeria monocytogenes , 1994 .

[12]  M. Doyle,et al.  Fate of enterohemorrhagic Escherichia coli O157:H7 in apple cider with and without preservatives , 1993, Applied and environmental microbiology.

[13]  R. C. Whiting,et al.  Differentiation of the Effects of pH and Lactic or Acetic Acid Concentration on the Kinetics of Listeria Monocytogenes Inactivation. , 1993, Journal of food protection.

[14]  K. Young,et al.  Acetic, lactic and citric acids and pH inhibition of Listeria monocytogenes Scott A and the effect on intracellular pH. , 1993, The Journal of applied bacteriology.

[15]  M. J. García,et al.  Energy production from L-malic acid degradation and protection against acidic external pH in Lactobacillus plantarum CECT 220 , 1992 .

[16]  F. Pagotto,et al.  The effect of acid shock on the heat resistance of Listeria monocytogenes , 1992 .

[17]  M. Hinton,et al.  The influence of temperature and organic matter on the bactericidal activity of short-chain organic acids on salmonellas. , 1992, The Journal of applied bacteriology.

[18]  R. G. Kroll,et al.  Induced acid tolerance in Listeria monocytogenes , 1992 .

[19]  R. Hutkins,et al.  Intracellular pH and Survival of Listeria monocytogenes Scott A in Tryptic Soy Broth Containing Acetic, Lactic, Citric, and Hydrochloric Acids. , 1991, Journal of food protection.

[20]  R. Buchanan,et al.  Effects of temperature and oxygen on the growth of Listeria monocytogenes at pH 4.5 , 1990 .

[21]  V. Scott,et al.  Growth, Inhibition, and Survival of Listeria monocytogenes as Affected by Acidic Conditions. , 1990, Journal of food protection.

[22]  J. G. Banks,et al.  Growth of Listeria monocytogenes at refrigeration temperatures. , 1990, The Journal of applied bacteriology.

[23]  R. Prescott,et al.  The effect of various acidulants on the growth of Listeria monocytogenes , 1989 .

[24]  E. H. Marth,et al.  Behavior of Listeria monocytogenes at 7, 13, 21, and 35°C in Tryptose Broth Acidified with Acetic, Citric, or Lactic Acid. , 1989, Journal of food protection.

[25]  K. M. Sorrells,et al.  Effect of pH, Acidulant, Time, and Temperature on the Growth and Survival of Listeria monocytogenes. , 1989, Journal of food protection.