Methods for improved recovery of Listeria monocytogenes from cheese
- PMID: 3145706
- PMCID: PMC204349
- DOI: 10.1128/aem.54.11.2643-2649.1988
Methods for improved recovery of Listeria monocytogenes from cheese
Abstract
Method of homogenization (Waring blender versus stomacher), type of diluent (tryptose broth [TB] versus aqueous 2% trisodium citrate), and temperature of diluent (20 versus 40 degrees C) were compared for recovery of Listeria monocytogenes from freshly made and ripened Colby cheese. By using direct plating on McBride listeria agar, significantly higher numbers of L. monocytogenes were recovered when cheese samples were (i) homogenized for 2 min with the blender rather than the stomacher (P less than 0.01), (ii) diluted in trisodium citrate rather than TB (P less than 0.01), and (iii) diluted in diluents at 40 rather than 20 degrees C (P less than 0.05). Based on these results, a new diluent/enrichment medium was developed by adding 2% trisodium citrate to TB (TBC). Despite superior results with the blender, biosafety concerns led to use of the stomacher for homogenization of cheese samples; hence, the stomaching time was increased to 3 min. Results obtained by direct plating indicated that recovery of L. monocytogenes from Colby cheese and from curd samples taken during manufacture of brick cheese increased when samples were diluted 1:10 in TBC at 45 degrees C and stomached for 3 min, as compared with similarly treated samples diluted in TB at 25 degrees C. A similar comparison of both diluents for recovery of L. monocytogenes from cold-pack cheese food yielded bacterial counts which were not significantly different. Recovery of L. monocytogenes from cold-enriched (at 4 degrees C for up to 8 weeks) samples of Colby cheese and cold-pack cheese food was generally similar for samples homogenized in TBC or TB.
Similar articles
-
Behavior of Listeria monocytogenes during manufacture and ripening of brick cheese.J Dairy Sci. 1989 Apr;72(4):838-53. doi: 10.3168/jds.S0022-0302(89)79176-1. J Dairy Sci. 1989. PMID: 2501363
-
Efficacy of direct plating media for recovering Listeria monocytogenes from foods.Int J Food Microbiol. 1990 Mar;10(2):143-55. doi: 10.1016/0168-1605(90)90062-a. Int J Food Microbiol. 1990. PMID: 2119210
-
Fate of Listeria monocytogenes During the Manufacture and Ripening of Blue Cheese.J Food Prot. 1989 Jul;52(7):459-465. doi: 10.4315/0362-028X-52.7.459. J Food Prot. 1989. PMID: 31003393
-
Listeria monocytogenes--threat to a safe food supply: a review.J Dairy Sci. 1990 Apr;73(4):912-28. doi: 10.3168/jds.S0022-0302(90)78748-6. J Dairy Sci. 1990. PMID: 2111832 Review.
-
Culture media and methods for the isolation of Listeria monocytogenes.Int J Food Microbiol. 1995 Jun;26(1):1-13. doi: 10.1016/0168-1605(93)e0027-o. Int J Food Microbiol. 1995. PMID: 7662515 Review.
Cited by
-
Role of a GntR-family response regulator LbrA in Listeria monocytogenes biofilm formation.PLoS One. 2013 Jul 23;8(7):e70448. doi: 10.1371/journal.pone.0070448. Print 2013. PLoS One. 2013. PMID: 23894658 Free PMC article.
-
Listeria monocytogenes intragastric and intraperitoneal approximate 50% lethal doses for mice are comparable, but death occurs earlier by intragastric feeding.Infect Immun. 1990 Sep;58(9):2940-5. doi: 10.1128/iai.58.9.2940-2945.1990. Infect Immun. 1990. PMID: 2117576 Free PMC article.
-
Listeria monocytogenes, a food-borne pathogen.Microbiol Rev. 1991 Sep;55(3):476-511. doi: 10.1128/mr.55.3.476-511.1991. Microbiol Rev. 1991. PMID: 1943998 Free PMC article. Review.
References
Publication types
MeSH terms
Substances
LinkOut - more resources
Full Text Sources