Agriculture Reference
In-Depth Information
QCL Analysis in the Tomato Supply Chain
Schouten et al. ( 2006 , 2010 ) determined the acceptance limits for both color and
firmness of round tomatoes when consumers want to buy them for direct consump-
tion and also for consumption after several days. As indicated before, the accep-
tance period (AP) consists of the period that all quality attributes are considered
acceptable and takes into account that tomatoes can first be unacceptable due to
being immature, then be acceptable, and then be unacceptable again, due to being
over-ripe. Based on a hybrid (kinetic-stochastic) quality model, calibrated on (non-
destructively measured) color and firmness data gathered at different storage tem-
peratures, predictions on the development of both color and firmness through time
at variable temperatures could be established. By combining this calibrated model
with the acceptance limits it becomes possible to predict the time it takes, depend-
ing on the chain temperature conditions, when a batch becomes acceptable and how
long the batch will stay acceptable.
The acceptance period model was calibrated for 10 tomato cultivars from one
Dutch breeder. All tomatoes from all cultivars were grown in the same greenhouse
and harvested on the same day for each maturation level, i.e. breaker, pink and red.
A tomato supply chain from a well-known Dutch producer group, known as Promi-
nent, was studied. From this study 12 different actual and possible supply chains
were designed. The chains were typical for different seasons, e.g. in the summer the
supply is large and so the chain duration lengthens, while in winter the supply is
small and the chain duration is short. When the tomatoes were harvested on Friday
there was a weekend effect prolonging the chain duration. Some of the results are
depicted in Fig. 14.3 .
Figure 14.3 shows the duration of the AP between 12 and 13 days for the best
Dutch tomato cultivar compared to the worst Dutch cultivar with an AP duration
varying between 1 and 3 days. Four scenarios depicted as horizontal bars are shown
starting at day 0 (harvest). The colors indicate the different chain temperatures the
tomato batch experiences throughout the chain. It is clear that a short AP (lower
plot) results in a batch that is still unacceptable at the moment the batch hits the
shelf. In most cases the tomatoes are far from optimal when displayed to the con-
sumer. Except in Scenario 3 (whole chain at 25 °C), where the tomatoes are mainly
overripe when the consumer can buy them. The only case that we have a good
match is in scenario 4 when the tomatoes are harvested in the pink stage of matu-
rity. It is clear that if tomatoes have a short AP duration this demands high precision
chain management. This situation could be dealt with, but that would mean an exact
knowledge of all chain conditions ahead of time and adapt accordingly. These are,
for now, unrealistic in fast flowing high volume chains like tomato chains. Even
for the best Dutch cultivar (upper plot) suboptimal chain performance may occur.
As we see in scenario 1 the chain is too short for the AP. A proper logistic decision
in this case would be to store the tomatoes or keep them at a higher temperature to
make sure they reach the shelf in an optimal state. Scenario 3, at 25 °C, shows that
part of the AP is lost due to early ripening within the chain. A proper logistic deci-
sion would be here to lower the chain temperature.
Search WWH ::




Custom Search