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Fate of Listeria spp. on parsley leaves grown in laboratory and field cultures
Author(s) -
Dreux N.,
Albagnac C.,
Carlin F.,
Morris C.E.,
NguyenThe C.
Publication year - 2007
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2007.03419.x
Subject(s) - listeria monocytogenes , listeria , biology , population , contamination , horticulture , food science , veterinary medicine , bacteria , ecology , medicine , genetics , demography , sociology
Aims: To investigate the population dynamics of Listeria monocytogenes and Listeria innocua on the aerial surfaces of parsley. Methods and Results: Under 100% relative humidity (RH) in laboratory and regardless of the inoculum tested (10 3 –10 8 CFU per leaf), counts of L. monocytogenes EGDe, LO28, LmP60 and L. innocua CIP 80‐12 tended towards approx. 10 5 CFU per leaf. Under low RH, Listeria spp. populations declined regardless to the inoculum size (10 4 –10 8 CFU per leaf). L. innocua CIP 80‐12 survived slightly better than L. monocytogenes in the laboratory and was used in field cultures. Under field cultures, counts of L. innocua decreased more rapidly than in the laboratory, representing a decrease of 9 log 10 in 2 days in field conditions compared to a decrease of 4·5 log 10 in 8 days in the laboratory. Counts of L. innocua on tunnel parsley cultures were always higher (at least by 100 times) than those on unprotected parsley culture. Conclusions: Even with a high inoculum and under protected conditions (i.e. plastic tunnels), population of L. monocytogenes on the surface of parsley on the field would decrease by several log 10 scales within 2 days. Significance and Impact of the Study: Direct contamination of aerial surfaces of parsley with L. monocytogenes (i.e. through contaminated irrigation water) will not lead to contaminated produce unless it occurs very shortly before harvest.