Fig 1.
Model of cross-contamination with Campylobacter spp. from artificially inoculated chicken skin to RTE lettuce via cooking salt.
Fig 2.
Transfer of Campylobacter from the contaminated chicken skin to cooking salt via unwashed hands, and from cooking salt to lettuce, according to the different initial skin surface contamination levels.
The presence/absence (qualitative transfer data) of the pathogen on salt and lettuce samples is indicated by the different colours. Quantitative transfer data (i. e. numbers of Campylobacter organisms) was achieved in four samples (a) 1.30 Log CFU/g lettuce; (b) 1.48 Log CFU/g lettuce; (c) 1.30 Log CFU/g cooking salt; (d) 1.00 Log CFU/g cooking salt.
Fig 3.
Survival of Campylobacter spp. in cooking salt.
Results are presented as survival/difference from the control calculated as Log (N/N0) (where N0 is the bacterial number in the controls at time zero, and N is the bacterial number at different times after inoculation). Columns present mean and standard deviation of four independent experiments.
Fig 4.
Transmission electron micrographs of cells of Campylobacter spp. after exposure to cooking salt at different time intervals showed spiral shaped cells even after 6 hours of exposure.
A) immediately after inoculation; B, 60 min; C, 180 min; D; 6 hours. Arrows represent bacterial cells with typical spiral shape of Campylobacter spp. Amplifications: A) 15000X; B) 20000X; C) 12000X; and D) 12000X. Bar represents 1 μm in Fig 4A), 4C) and 4D) and 0.5 μm in Fig 4B).