transport all fruitand vegetables at about7 ÎC. Thisis bad for the foodquality
(notnecessarily bad for the foodsafety)of tropical fruitsand convenience
products. Hence,the frequency of chilling injury of bananasand othertropical
fruits has increased and the shelf-lifeof pre-cut vegetableshas decreased.The
strongrise in salesof conveniencevegetable productscombinedwiththe trend
to transport theseproducts at too hightemperaturesis resultingin a growing
visibility of the shelf-lifeproblem.
Temperature abuseat unloading occursreasonablyfrequentwithtransports to
shops.At smallshopsthe goods receptionis not chilled.The driverleaves the
loadat receptionand sometimesno shoppersonnelare directlyavailable to
attend.We haveoccasionallyrecordedtimeperiodsof › to 2 hoursfor loadsleft
uncooled withour own datalogger tests of Dutchsupply chains.Again a
(modern)datalog system will assistthe transport operatorwheneverclaimsare
filedas a resultof temperature abuseat unloading. In orderto avoid these
situations,somesupermarketsallowdriversto bringthe loadto chilled cabinets
or onlyallowthe driverto unloadafterthe supermarketpersonnelare presentto
receive the chilledload.
Food transportationwithfrequentstops and many dooropeningsformsa
special challenge in maintainingthe temperatureof a conditionedtransport,
especiallyfor foodstuffs withlowspecific heatcapacities, suchas bakery
products. Lamellaeand air curtains at the doorsof the vehiclecan reducethe
heatleakageduring(un)loadingsignificantly.
In our modernsupply chainsan increasing amount of refrigeratedshipments
is air-freighted. Refrigerated air shipments havetheirownunique problems.
Sincenormal refrigerationunitsare forbiddenin aeroplanes, freightsare either
unchilled and insulatedor shipped in specialcontainerschilled withdry ice.
Mostrefrigerated loadsare wellpre-cooledand insulatedfor the flight.A very
limited numberof shipmentsmake use of the specially designedEnvirotainer.^8
This is an air-cargo sizedcontainer wheredry ice (solid carbon dioxide)can be
introduced in a separate cupboard. The carbon dioxide evaporates and chillsthe
load. A fan forces the air to circulate in the container.The relativehighrent
prices of theseEnvirotainerscurrentlylimittheiruse. Consequently,most loads
are pre-cooled and insulated.Temperature abusecan happenas a resultof slow
loading or unloading of planes.Whenfoodor flowers are flown overborders(to
other continents) the veterinaryor phytosanitaryinspectionservicefirst has to
clear the load.Sometimes it takesthema few hoursto attendand to inspectat
airports. The insulatedcontainerwill waitall that timeoutsidethe plane ± often
in full sunshine± untilthe inspectors approve it. A few hoursof full sunshine at
a tropicaldestination can havedisastrouseffectson the temperature of the load.
Improvedair cargo containers can be expected in the nearfuture,with,for
instance, electricPeltiercoolersand improvedinsulation materials.
Conditionedsea transports(reefer boats and refrigeratedcontainers)usually
perform outstandinglywellin comparison withconditionedtruck transport.In
north westEuropethe Coolboxx initiative (intermodalreefercontainersfor short
sea, rail and road)has improved the logistics of freshproduce duringthe last
402 Handbookof hygiene controlin the foodindustry