DF = data.frame(
    survey=as.factor( 1:5 ),
    plain=c( 13.8, 12.9, 25.9, 18.0, 15.2 ),
    butter=c( 11.7, 16.7, 29.8, 23.1, 20.2 ),
    beef=c( 14.0, 15.5, 27.8, 23.0, 19.0 ),
    bread=c( 12.6, 13.8, 25.0, 16.9, 13.7 )
)

library(reshape2)
DF_melt = melt(DF, id.vars=c('survey'), value.name='acceptance_percentage', variable.name='type')