Abstract
The survival and growth of two strains of Listeria monocytogenes on raw and cooked carrots stored at 5 and 15 degrees C and in carrot juice media at 30 degrees C were investigated. The influence of shredding, chlorine treatment, and packaging under an atmosphere containing 3% O2 and 97% N2 on the behavior of L. monocytogenes and naturally occurring microflora was determined. Populations of viable L. monocytogenes decreased upon contact with whole and shredded raw carrots but not cooked carrots. Viable populations also decreased in cell suspensions in which raw carrots were dipped. Small populations of L. monocytogenes detected on whole carrots immediately after dipping were essentially nondetectable after 7 days of storage at 5 or 15 degrees C. After a lag of 7 days at 5 degrees C, significant (P less than or equal to 0.05) increases in populations were detected on shredded carrots after 24 days of storage. Carrots stored at 5 or 15 degrees C spoiled before L. monocytogenes grew. Populations of mesophilic aerobes, psychrophiles, and yeasts and molds increased throughout storage at 5 and 15 degrees C. Cutting treatment (whole or shredded carrots), chlorine treatment, and modified-atmosphere packaging had no effect on the survival or growth of L. monocytogenes or naturally occurring microflora. The presence of raw carrot juice in tryptic phosphate broth at a concentration as low as 1% substantially reduced the maximum population of L. monocytogenes reached after 24 h at 30 degrees C. The anti-Listeria effect of carrots was essentially eliminated when the carrots were cooked.(ABSTRACT TRUNCATED AT 250 WORDS)
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- Amin M., Kurosaki F., Nishi A. Carrot phytoalexin alters the membrane permeability of Candida albicans and multilamellar liposomes. J Gen Microbiol. 1988 Jan;134(1):241–246. doi: 10.1099/00221287-134-1-241. [DOI] [PubMed] [Google Scholar]
- Beuchat L. R., Brackett R. E., Hao D. Y., Conner D. E. Growth and thermal inactivation of Listeria monocytogenes in cabbage and cabbage juice. Can J Microbiol. 1986 Oct;32(10):791–795. doi: 10.1139/m86-145. [DOI] [PubMed] [Google Scholar]
- Golden D. A., Beuchat L. R., Brackett R. E. Evaluation of selective direct plating media for their suitability to recover uninjured, heat-injured, and freeze-injured Listeria monocytogenes from foods. Appl Environ Microbiol. 1988 Jun;54(6):1451–1456. doi: 10.1128/aem.54.6.1451-1456.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heisick J. E., Wagner D. E., Nierman M. L., Peeler J. T. Listeria spp. found on fresh market produce. Appl Environ Microbiol. 1989 Aug;55(8):1925–1927. doi: 10.1128/aem.55.8.1925-1927.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ho J. L., Shands K. N., Friedland G., Eckind P., Fraser D. W. An outbreak of type 4b Listeria monocytogenes infection involving patients from eight Boston hospitals. Arch Intern Med. 1986 Mar;146(3):520–524. [PubMed] [Google Scholar]
- Schlech W. F., 3rd, Lavigne P. M., Bortolussi R. A., Allen A. C., Haldane E. V., Wort A. J., Hightower A. W., Johnson S. E., King S. H., Nicholls E. S. Epidemic listeriosis--evidence for transmission by food. N Engl J Med. 1983 Jan 27;308(4):203–206. doi: 10.1056/NEJM198301273080407. [DOI] [PubMed] [Google Scholar]
- Sizmur K., Walker C. W. Listeria in prepacked salads. Lancet. 1988 May 21;1(8595):1167–1167. doi: 10.1016/s0140-6736(88)91983-6. [DOI] [PubMed] [Google Scholar]
- Skovgaard N., Morgen C. A. Detection of Listeria spp. in faeces from animals, in feeds, and in raw foods of animal origin. Int J Food Microbiol. 1988 May;6(3):229–242. doi: 10.1016/0168-1605(88)90015-3. [DOI] [PubMed] [Google Scholar]
- Weis J., Seeliger H. P. Incidence of Listeria monocytogenes in nature. Appl Microbiol. 1975 Jul;30(1):29–32. doi: 10.1128/am.30.1.29-32.1975. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Welshimer H. J. Isolation of Listeria monocytogenes from vegetation. J Bacteriol. 1968 Feb;95(2):300–303. doi: 10.1128/jb.95.2.300-303.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]