The product and the system investigated
The product studied is one of the most common
brands of tomato ketchup sold in Sweden; it is marketed
in 1 kg red plastic bottles. The complete system investigated
is shown in Fig. 1. The packaging systems for tomato
paste and ketchup are shown in Figs. 2 and 3,
respectively. The life cycle can be described briefly as
follows. Tomatoes are grown and processed into tomato
paste in the Mediterranean countries; then the tomato
paste is transported to Sweden and processed (together
with other ingredients and water) into ketchup. Thereafter,
the ketchup is packaged, delivered to retailers and,
finally, consumed. The tomato paste is packed in aseptic
bags which are placed in steel barrels. Each bag contains
200 l of tomato paste. The plastic bottle used for ketchup
is made of polypropylene (PP) and is blow-moulded. It
consists of five layers: an inner wall of PP; adhesive; a
barrier layer of ethylenevinylalcohol (EVOH); adhesive;
and an outer wall of PP.