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Transmission electron microscopy study of Listeria monocytogenes treated with nisin in combination with either grape seed or green tea extract.
J Food Prot. 2008 Oct; 71(10):2105-9.JF

Abstract

The objective of this study was to use transmission electron microscopy to investigate the morphological changes that occurred in Listeria monocytogenes cells treated with grape seed extract (GSE), green tea extract (GTE), nisin, and combinations of nisin with either GSE or GTE. The test solutions were prepared with (i) 1% GSE, 1% GTE, 6,400 IU of nisin, and the combination of these dilutions with nisin or with (ii) the pure major phenolic constituents of GSE (0.02% epicatechin plus 0.02% catechin) or GTE (0.02% epicatechin plus 0.02% caffeic acid) and their combinations with 6,400 IU of nisin in tryptic soy broth with 0.6% yeast extract (TSBYE). Test solutions were inoculated with L. monocytogenes at approximately 10(6) CFU/ml and incubated for 3 or 24 h at 37 degrees C. After 3 h of incubation, cells were harvested and evaluated under a transmission electron microscope (JEOL-100 CX) operating at 80 kV (50,000X). Microscopic examination revealed an altered cell membrane and condensed cytoplasm when L. monocytogenes cells were exposed to a combination of nisin with either GSE or GTE or to pure compounds of the major phenolic constituents in combination. After 24 h of incubation at 37 degrees C, the combinations of nisin with GSE and nisin with GTE reduced the L. monocytogenes population to undetectable levels and 3.7 log CFU/ml, respectively. These observations indicate that the combination of nisin with either GSE or GTE had a synergistic effect, and the combinations of nisin with the major phenolic constituents were most likely associated with the L. monocytogenes cell damage during inactivation in TSBYE at 37 degrees C.

Authors+Show Affiliations

Department of Food Science, University of Arkansas, 2650 North Young Avenue, Fayetteville, Arkansas 72704, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18939761

Citation

Sivarooban, T, et al. "Transmission Electron Microscopy Study of Listeria Monocytogenes Treated With Nisin in Combination With Either Grape Seed or Green Tea Extract." Journal of Food Protection, vol. 71, no. 10, 2008, pp. 2105-9.
Sivarooban T, Hettiarachchy NS, Johnson MG. Transmission electron microscopy study of Listeria monocytogenes treated with nisin in combination with either grape seed or green tea extract. J Food Prot. 2008;71(10):2105-9.
Sivarooban, T., Hettiarachchy, N. S., & Johnson, M. G. (2008). Transmission electron microscopy study of Listeria monocytogenes treated with nisin in combination with either grape seed or green tea extract. Journal of Food Protection, 71(10), 2105-9.
Sivarooban T, Hettiarachchy NS, Johnson MG. Transmission Electron Microscopy Study of Listeria Monocytogenes Treated With Nisin in Combination With Either Grape Seed or Green Tea Extract. J Food Prot. 2008;71(10):2105-9. PubMed PMID: 18939761.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Transmission electron microscopy study of Listeria monocytogenes treated with nisin in combination with either grape seed or green tea extract. AU - Sivarooban,T, AU - Hettiarachchy,N S, AU - Johnson,M G, PY - 2008/10/23/pubmed PY - 2008/12/17/medline PY - 2008/10/23/entrez SP - 2105 EP - 9 JF - Journal of food protection JO - J Food Prot VL - 71 IS - 10 N2 - The objective of this study was to use transmission electron microscopy to investigate the morphological changes that occurred in Listeria monocytogenes cells treated with grape seed extract (GSE), green tea extract (GTE), nisin, and combinations of nisin with either GSE or GTE. The test solutions were prepared with (i) 1% GSE, 1% GTE, 6,400 IU of nisin, and the combination of these dilutions with nisin or with (ii) the pure major phenolic constituents of GSE (0.02% epicatechin plus 0.02% catechin) or GTE (0.02% epicatechin plus 0.02% caffeic acid) and their combinations with 6,400 IU of nisin in tryptic soy broth with 0.6% yeast extract (TSBYE). Test solutions were inoculated with L. monocytogenes at approximately 10(6) CFU/ml and incubated for 3 or 24 h at 37 degrees C. After 3 h of incubation, cells were harvested and evaluated under a transmission electron microscope (JEOL-100 CX) operating at 80 kV (50,000X). Microscopic examination revealed an altered cell membrane and condensed cytoplasm when L. monocytogenes cells were exposed to a combination of nisin with either GSE or GTE or to pure compounds of the major phenolic constituents in combination. After 24 h of incubation at 37 degrees C, the combinations of nisin with GSE and nisin with GTE reduced the L. monocytogenes population to undetectable levels and 3.7 log CFU/ml, respectively. These observations indicate that the combination of nisin with either GSE or GTE had a synergistic effect, and the combinations of nisin with the major phenolic constituents were most likely associated with the L. monocytogenes cell damage during inactivation in TSBYE at 37 degrees C. SN - 0362-028X UR - https://www.unboundmedicine.com/medline/citation/18939761/Transmission_electron_microscopy_study_of_Listeria_monocytogenes_treated_with_nisin_in_combination_with_either_grape_seed_or_green_tea_extract_ L2 - https://meridian.allenpress.com/jfp/article-lookup/doi/10.4315/0362-028x-71.10.2105 DB - PRIME DP - Unbound Medicine ER -