Electron beam and gamma irradiation effectively reduce Listeria monocytogenes populations on chopped romaine lettuce

被引:19
作者
Mintier, AM [1 ]
Foley, DM [1 ]
机构
[1] Chapman Univ, Dept Biol Sci, Orange, CA 92866 USA
关键词
D O I
10.4315/0362-028X-69.3.570
中图分类号
Q81 [生物工程学(生物技术)]; Q93 [微生物学];
学科分类号
071005 ; 0836 ; 090102 ; 100705 ;
摘要
Fresh, chopped romaine lettuce contaminated with a seven-strain cocktail of Listeria monocytogenes (in a solution containing approximately 10(8) organisms per ml) that had attained a level of contamination of between 7 and 8 log CFU/g was packaged in 15-g samples. The lettuce was irradiated with a Co-60 source at 1.15 or 0.51 kGy and then stored at VC. In addition, samples contaminated with isolated strains 16397, 0733, and 1992 were subjected to either electron beam irradiation at doses ranging from 0.3 to 1.2 kGy or gamma irradiation at 0.56 kGy without subsequent refrigerated storage. All postirradiation and control samples were diluted with Butterfield's phosphate buffer and plated in duplicate on modified Oxford media. Samples that received electron beam or gamma irradiation without subsequent refrigerated storage were also plated in duplicate on modified Oxford media plates coated with two 7-ml layers of basal yeast extract agar. Electron beam irradiation yielded D-10-values (the dose required to eliminate 90% of the microbial population) of 0.16, 0.17, and 0.19 kGy for strains 16397, 0733, and 1992, respectively. The corresponding log reductions obtained for these same three strains at 0.56 kGy of gamma irradiation were 2.91, 2.62, and 2.66 log, respectively. Gamma irradiation at 1.15 and 0.51 kGy with subsequent refrigerated storage (4 degrees C) reduced populations by > 5 and > 2 log, respectively, compared with controls. Neither the irradiated samples nor the control samples showed increases in population during the storage periods. Our results indicate that low-dose irradiation can effectively reduce or eliminate L. monocyrogenes on chopped romaine lettuce, improving the safety of ready-to-cat salads.
引用
收藏
页码:570 / 574
页数:5
相关论文
共 37 条
[1]   Efficacy of chlorine and a peroxyacetic acid sanitizer in killing Listeria monocytogenes on iceberg and Romaine lettuce using simulated commercial processing conditions [J].
Beuchat, LR ;
Adler, BB ;
Lang, MM .
JOURNAL OF FOOD PROTECTION, 2004, 67 (06) :1238-1242
[2]   SURVIVAL AND GROWTH OF LISTERIA-MONOCYTOGENES ON LETTUCE AS INFLUENCED BY SHREDDING, CHLORINE TREATMENT, MODIFIED ATMOSPHERE PACKAGING AND TEMPERATURE [J].
BEUCHAT, LR ;
BRACKETT, RE .
JOURNAL OF FOOD SCIENCE, 1990, 55 (03) :755-&
[3]   Effect of gamma irradiation on Listeria monocytogenes in frozen, artificially contaminated sandwiches [J].
Clardy, S ;
Foley, DM ;
Caporaso, F ;
Calicchia, ML ;
Prakash, A .
JOURNAL OF FOOD PROTECTION, 2002, 65 (11) :1740-1744
[4]   Sensorial and chemical quality of gamma-irradiated fresh-cut iceberg lettuce in modified atmosphere packages [J].
Fan, XT ;
Sokorai, KJB .
JOURNAL OF FOOD PROTECTION, 2002, 65 (11) :1760-1765
[5]  
Farkas Jozsef, 1997, Advances in Food Sciences, V19, P111
[6]   Irradiation and chlorination effectively reduces Escherichia coli O157:H7 inoculated on cilantro (Coriandrum sativum) without negatively affecting quality [J].
Foley, D ;
Euper, M ;
Caporaso, F ;
Prakash, A .
JOURNAL OF FOOD PROTECTION, 2004, 67 (10) :2092-2098
[7]   Reduction of Escherichia coli O157:H7 in shredded iceberg lettuce by chlorination and gamma irradiation [J].
Foley, DM ;
Dufour, A ;
Rodriguez, L ;
Caporaso, F ;
Prakash, A .
RADIATION PHYSICS AND CHEMISTRY, 2002, 63 (3-6) :391-396
[8]   Elimination of Listeria monocytogenes and changes in physical and sensory qualities of a prepared meal following gamma irradiation [J].
Foley, DM ;
Reher, E ;
Caporaso, F ;
Trimboli, S ;
Musherraf, Z ;
Prakash, A .
FOOD MICROBIOLOGY, 2001, 18 (02) :193-204
[9]   Reduction and survival of Listeria monocytogenes in ready-to-eat meats after irradiation [J].
Foong, SCC ;
Gonzalez, GL ;
Dickson, JS .
JOURNAL OF FOOD PROTECTION, 2004, 67 (01) :77-82
[10]   Survey of Listeria monocytogenes in ready-to-eat foods [J].
Gombas, DE ;
Chen, YH ;
Clavero, RS ;
Scott, VN .
JOURNAL OF FOOD PROTECTION, 2003, 66 (04) :559-569