More Ice Is Not Always Better: Chilling Injury and Falling Saleable Value in Over-Iced Tropical Produce

A widely held belief at small markets is that adding more ice to a cold box always increases the value that can be sold that day: colder, on this view, is safer. This paper shows by computation that the belief does not survive for tropical produce. Tropical crops are injured by cold itself, below crop-specific thresholds, and injury grows with depth below the threshold and time spent there. Using a stated model for a 20 kg load traded for 8 hours at 32 °C ambient, with interior temperature falling as the ice ratio r — ice mass divided by produce mass — rises, the paper computes heat loss, chilling injury, ice cost and net saleable value for banana, mango, papaya, avocado and, as a temperate control, lettuce. Banana reaches its best net value of $20.51 at r = 0.21, enters chilling conditions at r = 0.322, and at r = 1.0 retains only $1.73, a fall of 91.6% from its grid optimum. Mango peaks at $54.49 at r = 0.35 and falls to $25.00 at r = 1.0. Lettuce, with no chilling threshold above 0 °C in the model, loses only 8.6% between its grid optimum and r = 1.0, mainly through ice cost. The ice fraction above which added ice reduces value is therefore stated for each crop. All results are computed from stated assumptions. SIMULATED, NOT MEASURED.