Field Trimming of Lettuce: Effects on Package Weight and Market Quality

Excerpts from the report: The weight of lettuce packed in cartons has increased progressively, largely due to pressure from wholesale buyers and the subsequent selling of lettuce on a weight basis at retail. Aside from the obvious effect of this practice on gross weights of lettuce packages, the effect on quality should be considered. Placing excessive amounts of lettuce in a carton would appear to be a primary cause of bruising and crushing of the heads. A reduction of package weights might be accomplished by trimming the heads in the field to reduce the number of wrapper leaves remaining in the pack. Five to six wrapper leaves are commonly left on the heads. It has been suggested that decay may be reduced by trimmming, as outer wrapper leaves are contaminated with decay-causing organisms. The fact that they are older chronologically and physiologically makes the wrapper leaves more susceptible to decay than the younger leaves toward the center of the head. At the request of industry representatives, tests were conducted to relate various degrees of trimming of the heads to package weight, bruising, decay, and other quality factors.