Elimination of insect, disease ,vermin, and similar unwanted plagues of pests by chemical inputs. • Fungi and Bacteria – main cause. • Parasite (on living matter) / saprophytes (dead produce). • fungi - pH (2.5 – 6) ; bacteria - neutral • Chlorine & sulfur dioxide • Chlorine –sanitizer ; 50 to 200 ppm in water to reduce the number of microorganisms present on the surface of the fruit