Behavior of Listeria monocytogenes in the presence of methylxanthines-caffeine and theobromine
Two components of cocoa powder, caffeine (1, 3, 7-trimethylxanthine) and theobromine (3,7-dimethylxanthine), were evaluated for their effect on growth of L. monocytogenes strain V7. Caffeine (0.5 percent) and theobromine (2.5 percent) were added singly or in combination to skim milk or a modified tryptose phosphate broth (MTPB), which were sterilized, inoculated to contain ca. 1 x 10 exponent 3 CFU L. monocytogenes/ml, and incubated at 30 grade centigrade. Both compounds allowed some growth of the pathogen; however, longer lag phases occurred in samples with (6 to 9 h) rather than without (minor 3 h) caffeine. Generation times at 30 grade centigrade ranged from 1.10 h (2.5 percent theobromine in broth) to 2.28 h (2.5 percent theobromine plus 0.5 percent caffeine in milk). Generation times were significantly (p minor 0.05) lengthened in the presence (2.17 h) rather than in the absence (1.2 h) of caffeine. Populations in samples without caffeine were more than ten times greater (8.57 log 10 CFU/ml) than in samples with caffeine (7.21 log 10 CFU/ml). Theobromine concentration (0 or 2.5 percent) and substrate (MTPB or skim milk) had only limited effects on growth of the pathogen. The change in pH of the medium was a function of the extent of growth of L. monocytogenes and the buffering capacity of the substrate. A smaller pH change (0.09 unit) occurred in the milk medium than in broth (0.48 unit) because of the minimal buffering capacity of the 0.2 percent tryptose solution. Samples with caffeine had a small decrease in pH (0.07 unit) because growth of L. monocytogenes was inhibited and thus acid production was minimal.
Main Authors: | , |
---|---|
Format: | biblioteca |
Published: |
Ene
|
Subjects: | CACAO EN POLVO, LISTERIA MONOCYTOGENES, CAFEINA, TEOBROMINA, XANTINAS, POLUCION, |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
id |
KOHA-OAI-BVE:71224 |
---|---|
record_format |
koha |
spelling |
KOHA-OAI-BVE:712242020-02-03T21:38:18ZBehavior of Listeria monocytogenes in the presence of methylxanthines-caffeine and theobromine 103949 Pearson, L.J. 90661 Marth, E.H. Ene 1990Two components of cocoa powder, caffeine (1, 3, 7-trimethylxanthine) and theobromine (3,7-dimethylxanthine), were evaluated for their effect on growth of L. monocytogenes strain V7. Caffeine (0.5 percent) and theobromine (2.5 percent) were added singly or in combination to skim milk or a modified tryptose phosphate broth (MTPB), which were sterilized, inoculated to contain ca. 1 x 10 exponent 3 CFU L. monocytogenes/ml, and incubated at 30 grade centigrade. Both compounds allowed some growth of the pathogen; however, longer lag phases occurred in samples with (6 to 9 h) rather than without (minor 3 h) caffeine. Generation times at 30 grade centigrade ranged from 1.10 h (2.5 percent theobromine in broth) to 2.28 h (2.5 percent theobromine plus 0.5 percent caffeine in milk). Generation times were significantly (p minor 0.05) lengthened in the presence (2.17 h) rather than in the absence (1.2 h) of caffeine. Populations in samples without caffeine were more than ten times greater (8.57 log 10 CFU/ml) than in samples with caffeine (7.21 log 10 CFU/ml). Theobromine concentration (0 or 2.5 percent) and substrate (MTPB or skim milk) had only limited effects on growth of the pathogen. The change in pH of the medium was a function of the extent of growth of L. monocytogenes and the buffering capacity of the substrate. A smaller pH change (0.09 unit) occurred in the milk medium than in broth (0.48 unit) because of the minimal buffering capacity of the 0.2 percent tryptose solution. Samples with caffeine had a small decrease in pH (0.07 unit) because growth of L. monocytogenes was inhibited and thus acid production was minimal.Two components of cocoa powder, caffeine (1, 3, 7-trimethylxanthine) and theobromine (3,7-dimethylxanthine), were evaluated for their effect on growth of L. monocytogenes strain V7. Caffeine (0.5 percent) and theobromine (2.5 percent) were added singly or in combination to skim milk or a modified tryptose phosphate broth (MTPB), which were sterilized, inoculated to contain ca. 1 x 10 exponent 3 CFU L. monocytogenes/ml, and incubated at 30 grade centigrade. Both compounds allowed some growth of the pathogen; however, longer lag phases occurred in samples with (6 to 9 h) rather than without (minor 3 h) caffeine. Generation times at 30 grade centigrade ranged from 1.10 h (2.5 percent theobromine in broth) to 2.28 h (2.5 percent theobromine plus 0.5 percent caffeine in milk). Generation times were significantly (p minor 0.05) lengthened in the presence (2.17 h) rather than in the absence (1.2 h) of caffeine. Populations in samples without caffeine were more than ten times greater (8.57 log 10 CFU/ml) than in samples with caffeine (7.21 log 10 CFU/ml). Theobromine concentration (0 or 2.5 percent) and substrate (MTPB or skim milk) had only limited effects on growth of the pathogen. The change in pH of the medium was a function of the extent of growth of L. monocytogenes and the buffering capacity of the substrate. A smaller pH change (0.09 unit) occurred in the milk medium than in broth (0.48 unit) because of the minimal buffering capacity of the 0.2 percent tryptose solution. Samples with caffeine had a small decrease in pH (0.07 unit) because growth of L. monocytogenes was inhibited and thus acid production was minimal.CACAO EN POLVOLISTERIA MONOCYTOGENESCAFEINATEOBROMINAXANTINASPOLUCIONJournal of Food Protection (EUA) |
institution |
IICA |
collection |
Koha |
country |
Costa Rica |
countrycode |
CR |
component |
Bibliográfico |
access |
En linea |
databasecode |
cat-sibiica |
tag |
biblioteca |
region |
America Central |
libraryname |
Sistema de Bibliotecas IICA/CATIE |
topic |
CACAO EN POLVO LISTERIA MONOCYTOGENES CAFEINA TEOBROMINA XANTINAS POLUCION CACAO EN POLVO LISTERIA MONOCYTOGENES CAFEINA TEOBROMINA XANTINAS POLUCION |
spellingShingle |
CACAO EN POLVO LISTERIA MONOCYTOGENES CAFEINA TEOBROMINA XANTINAS POLUCION CACAO EN POLVO LISTERIA MONOCYTOGENES CAFEINA TEOBROMINA XANTINAS POLUCION 103949 Pearson, L.J. 90661 Marth, E.H. Behavior of Listeria monocytogenes in the presence of methylxanthines-caffeine and theobromine |
description |
Two components of cocoa powder, caffeine (1, 3, 7-trimethylxanthine) and theobromine (3,7-dimethylxanthine), were evaluated for their effect on growth of L. monocytogenes strain V7. Caffeine (0.5 percent) and theobromine (2.5 percent) were added singly or in combination to skim milk or a modified tryptose phosphate broth (MTPB), which were sterilized, inoculated to contain ca. 1 x 10 exponent 3 CFU L. monocytogenes/ml, and incubated at 30 grade centigrade. Both compounds allowed some growth of the pathogen; however, longer lag phases occurred in samples with (6 to 9 h) rather than without (minor 3 h) caffeine. Generation times at 30 grade centigrade ranged from 1.10 h (2.5 percent theobromine in broth) to 2.28 h (2.5 percent theobromine plus 0.5 percent caffeine in milk). Generation times were significantly (p minor 0.05) lengthened in the presence (2.17 h) rather than in the absence (1.2 h) of caffeine. Populations in samples without caffeine were more than ten times greater (8.57 log 10 CFU/ml) than in samples with caffeine (7.21 log 10 CFU/ml). Theobromine concentration (0 or 2.5 percent) and substrate (MTPB or skim milk) had only limited effects on growth of the pathogen. The change in pH of the medium was a function of the extent of growth of L. monocytogenes and the buffering capacity of the substrate. A smaller pH change (0.09 unit) occurred in the milk medium than in broth (0.48 unit) because of the minimal buffering capacity of the 0.2 percent tryptose solution. Samples with caffeine had a small decrease in pH (0.07 unit) because growth of L. monocytogenes was inhibited and thus acid production was minimal. |
format |
|
topic_facet |
CACAO EN POLVO LISTERIA MONOCYTOGENES CAFEINA TEOBROMINA XANTINAS POLUCION |
author |
103949 Pearson, L.J. 90661 Marth, E.H. |
author_facet |
103949 Pearson, L.J. 90661 Marth, E.H. |
author_sort |
103949 Pearson, L.J. |
title |
Behavior of Listeria monocytogenes in the presence of methylxanthines-caffeine and theobromine |
title_short |
Behavior of Listeria monocytogenes in the presence of methylxanthines-caffeine and theobromine |
title_full |
Behavior of Listeria monocytogenes in the presence of methylxanthines-caffeine and theobromine |
title_fullStr |
Behavior of Listeria monocytogenes in the presence of methylxanthines-caffeine and theobromine |
title_full_unstemmed |
Behavior of Listeria monocytogenes in the presence of methylxanthines-caffeine and theobromine |
title_sort |
behavior of listeria monocytogenes in the presence of methylxanthines-caffeine and theobromine |
publishDate |
Ene |
work_keys_str_mv |
AT 103949pearsonlj behavioroflisteriamonocytogenesinthepresenceofmethylxanthinescaffeineandtheobromine AT 90661martheh behavioroflisteriamonocytogenesinthepresenceofmethylxanthinescaffeineandtheobromine |
_version_ |
1756057488443047936 |