title: Behavior of Listeria monocytogenes in the presence of gluconic acid and during preparation of cottage cheese curd using gluconic acid.
abstract: Unrestricted or minimally restricted growth of Listeria monocytogenes strain V7 occurred 1) at 13 degrees C in tryptose broth with .125 or .25% gluconic acid or .1 to .3% glucono-delta-lactone, 2) at 13 degrees C in milk with .125 to 1.0% gluconic acid or .5 or 1.0% glucono-delta-lactone, 3) at 35 degrees C in tryptose broth with .125 to .5% gluconic acid or .1 to 5% glucono-delta-lactone, and 4) at 35 degrees C in milk with .125 to 1.0% gluconic acid or .5 to 1.5% glucono-delta-lactone. Limited growth of L. monocytogenes occurred 1) at 13 degrees C with .375 or .5% gluconic acid or .3 or .4% glucono-delta-lactone, 2) at 13 degrees C in milk with 1.5% glucono-delta-lactone, 3) at 35 degrees C in tryptose broth with .75% glucono-delta-lactone, and 4) at 35 degrees C in milk with 2.0% glucono-delta-lactone. Partial to complete inactivation of L. monocytogenes occurred 1) at 13 degrees C in tryptose broth with .75 to 1.5% gluconic acid or .75 or 1.0% glucono-delta-lactone, 2) at 13 degrees C in milk with 1.5% gluconic acid or 2.0 to 3.0% glucono-delta-lactone, 3) at 35 degrees C in tryptose broth with .75 to 1.5% gluconic acid or 1.0% glucono-delta-lactone, and 4) at 35 degrees C in milk with 1.5% gluconic acid or 2.5 or 3.0% glucono-delta-lactone. Milk containing L. monocytogenes was coagulated with gluconic acid, HCl, or rennet, and cottage cheese curd was prepared. After cooking, numbers of the pathogen in curd or whey from rennet-coagulated milk were reduced by ca. 1.5 and 2.5 orders, respectively. Small numbers of survivors appeared in curd but not in whey of HCl-coagulated milk. No survivors were detected in curd or whey of gluconic acid-coagulated milk.
authors.affiliation: Department of Food Science, University of Wisconsin-Madison 53706.
authors.forename: M A
authors.initials: MA
authors.lastname: el-Shenawy
authors.forename: E H
authors.initials: EH
authors.lastname: Marth
mesh_terms: D000818:Animals; D002611:Cheese; D015169:Colony Count, Microbial; D005516:Food Microbiology; D005942:Gluconates / Q000378:metabolism*; D008089:Listeria monocytogenes / Q000254:growth & development*; D008892:Milk / Q000382:microbiology*; D013696:Temperature
chemical_list: D005942:Gluconates; C030691:gluconic acid