Background In the early 20 century, California produced only little lettuce . For 1909, Knott and Tavernetti [4] reported that lettuce was produced on 595 acres in California, which corresponded to 11% of the total U.S. acreage. Lettuce production increased dramatically in the 1920s (Figure 1). While 6,100 acres were harvested in 1919 , the harvested area reached 112,000 acres by 1930 . The mar...

Lettuce mosaic, caused by the potyvirus LMV, is a serious viral disease of lettuce crops world-wide. Beside seed control, one of the leading strategies to control LMV is the use of the recessive resistance genes mo11 and mo12. In an attempt to characterize the functional role of the translation initiation factor eIF4E in lettuce susceptibility to LMV, we cloned Ls-eIF4E cDNAs from a collection ...

Lettuce (Lactuca sativa L.) is one of the most important leafy vegetable that is consumed during its vegetative growth. The transition from vegetative to reproductive growth is induced by high temperature, which has significant economic effect on lettuce production. However, the progression of floral transition and the molecular regulation of bolting are largely unknown. Here we morphologically...

BACKGROUND An outbreak of Escherichia coli O157:H7 infections in Connecticut and Illinois during May 28 to June 27, 1996, was investigated to determine the source of infections. METHODS Independent case-control studies were performed in both states. Pulsed-field gel electrophoresis (PFGE) was performed on E. coli O157:H7 isolates. A case-patient was defined as a Connecticut or northern Illino...

The potential for lettuce field-coring harvesting knives to cross-contaminate lettuce heads with pathogens was evaluated. Rings and blades of the harvest knives artificially contaminated with Escherichia coli O157:H7 (EHEC), were used to core three successive heads of iceberg lettuce. The coring rings and blades were inoculated by dipping into soils containing EHEC at concentration ranges of 1-...

Aims: The objective of this study was to determine the influence of mild heat treatment, storage temperature and storage time on the survival and growth of Listeria monocytogenes inoculated onto cut iceberg lettuce leaves. Methods and Results: Before or after inoculation with L. monocytogenes, cut iceberg lettuce leaves were dipped in water (20 or 50°C), containing or not 20 mg l chlorine, for ...