Survival of Listeria monocytogenes in Fruit Juices During Refrigerated and Temperature-Abusive Storage

Survival of Listeria monocytogenes in apple, orange, red grape, and white grape juice was evaluated. A six-strain cocktail of L. monocytogenes was used to inoculate (approx. 7 log cfu/ml) fruit juices, which were stored at 4, 10 and 24°C for up to 61 days. Inoculated red grape juice was stored for up to 5 hours only. Samples were withdrawn at appropriate intervals, neutralized with 1.0 N NaOH, serially diluted in 0.1% peptone water, and surface plated onto Tryptic Soy Agar + 0.6% Yeast Extract (TSAYE) and Modified Oxford Agar (MOX), followed by incubation at 32°C for 48 hours. When L. monocytogenes was no longer detected by direct plating, samples were enriched for L. monocytogenes using Listeria Enrichment Broth (LEB), followed by isolation on MOX. L. monocytogenes remained viable in white grape, apple, and orange juices for up to 12, 24 and 61 days, respectively. Over time, recovery of Listeria on TSAYE versus MOX was not significantly different (P>0.05), indicating that limited acid-injury developed during storage. The results of this study demonstrate the ability of L. monocytogenes to survive in apple, orange, and white grape juices during refrigerated and abusive storage conditions. Therefore, measures to prevent or eliminate L. monocytogenes in the fruit juice-processing environment are necessary to ensure the safety of juice products for public consumption.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Food Science and Technology

Department dc:contributor.department

Food Science and Technology

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2003

Author dc:creator

• Piotrowski, Christine Lelia

Chair dc:contributor.committeechair

• Williams, Robert C.

Committee members dc:contributor.committeemember

• Sumner, Susan S.
• Marcy, Joseph E.

• acid
• juice
• pH
• cider
• Listeria monocytogenes

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-11142003-180132

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/9619