Washing fresh fruits and vegetables: lessons from treatment of tomatoes and potatoes with water.
Bartz, J. A.;
Dairy, Food and Environmental Sanitation Year: 1999 Vol: 19 Issue: 12 Pages: 853-864 Ref: 44 ref.
1999
บทคัดย่อ
Bacterial soft rot development in storage can be used to measure the effect of prior contact of potatoes or tomatoes with water containing Erwinia carotovora subsp. carotovora. Immersion of either tomato fruit or potato tubers in water containing log10 4.0 CFU/ml or more of E. c. carotovora led to an increased incidence and severity of soft rot above the base level for the test lot (with no postharvest treatment). Decay increased as populations of pathogens in the water increased. Wash water could infiltrate intercellular spaces in tomato or potato tissues by temperature-, time- and pressure-dependent processes. Infiltration occurred only when the water pressure on the product surface overcame the internal gas pressure and the hydrophobic nature of the product surface. When infiltration occurred, the spores or cells of pathogens suspended in the water became internalized in the product. Addition of detergents (surfactants) to water promoted infiltration, apparently by reducing the surface tensio
n of the water at the air-water interface at pores leading into the fruit or tuber. Addition of chlorine to water prior to adding products could prevent transfer of pathogens from the water to infection courts on the product. However, once the product was inoculated, chlorinated water would reduce but not prevent the subsequent development of decay. Washing freshly inoculated potatoes in clean tap water did not eliminate the effect of the inoculation. The addition of chlorine to the water used to infiltrate surface contaminated tomatoes reduced but did not prevent the subsequent development of decay. Thorough air-drying (up to 3 h) of potatoes that had been washed in contaminated water reduced the soft rot potential associated with washing in contaminated water.