Researchers have been using computational methods : computational fluid dynamics or CFD ’ s , particularly , the finite volume method , to analyse the airflow and heat transfer performances , and computational structural dynamics or CSD ’ s , particularly , the finite element method , to analyse the loss of compression strength due to vent-holes .

Models are validated using actual testing : wind tunnel based forced aircooling system to study the produce cooling kinetics and box compression test machine for the package industry

Based on experimental data , results show that the loss in strength can range between 10 – 40 % on addition of vent and hand holes on cartons , and reasonable increase in cooling rates are only achieved with increase in carton face ventilation area only up to 7 – 8 %. This should be combined by looking at through-flow patterns as well .

With regards to internal packaging components , increasing awareness of consumers to the environmental degradation of especially disposable plastic packaging , means packers and suppliers must devise means to cut back and eventually eliminate plastic packaging from fruit and vegetables . But also , there , airflow patterns should be looked at and adapted to the proper airflow system .

Brilliant . In theory . As we all know , in theory there is no difference between

to practical – it does not happen does it … it simply does not get implemented at farm level , and that is , as far as I am concerned , the only level that counts .

Forget the laboratories . If all of the theory does not result in tangible and implemented solutions for the farm , that is , the end user on production level , what is the use of all this ?

A lot of cartons used in the industry are , from an airflow point of view , appalling , and this also has some serious quality consequences . And that is not all : on land one cools horizontally , in the container one holds the temperature vertically … Do you see the difference ? A container is made to hold temperature , not cool down .

The first and most important law , as I have mentioned in a previous article , is that you should never ever forget that nature never ever breaks her own laws .

Firstly then , one must understand that

Jan Lievens , born in Belgium , is a graduate civil engineering ( B ) and international senior consultant for engineered applied postharvest technology at UTE South Africa . With over 20 years of experience in this field , he is widely regarded as a specialist in the fruit- , vegetable- and flower industry with regards to humidity , airborne bacteria and ethylene removal , both locally and internationally . Furthermore , he also designed airflow-friendly packaging systems for the industry with proven results .

to study the structural dynamics . Studies

theory and practice , but in practice there

air formed the earth ' s early atmosphere .

on the rate and uniformity of produce cooling and the loss of structural strength in corrugated cartons as a function of size , shape , and location of vent-holes are reviewed too .

is . Guess what , all of the brilliant papers and efforts are by some of the most brilliant postharvest theoretical orientated people , but in practice you all know the answer , theory does not translate

Most of the earth ' s early atmosphere was created in the first one million years after solidification ( 4.4 billion years ago ). Carbon dioxide , nitrogen , and water vapor dominated . So , it has been around

for an exceptionally long time , is very , very smart , and always takes the path of least resistance and the shortest route .

If the carton , inner packaging , and cooling tunnel are not designed to guide

All photos supplied by Jan Lievens

Various box carton designs used for packing of various fruits .