Caballero B. (ed.) Encyclopaedia of Food Science, Food Technology and Nutrition. Ten-Volume Set

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approach, the revenue-generating role of customer

service and its use as a tool of competition have

increasingly received attention. Logistics defines cus-

tomer service as ’a process for providing significant

value-added benefits to the supply chain in a cost-

efficient way.’

0042 In models of logistic operations, customer service is

generally considered as a constraint which must be

met while minimizing costs. More attention, however,

should be given to the maximization of customer ser-

vice within cost constraints. In this perspective, cus-

tomer service becomes an instrument of competition.

0043 Relevance of time and place utilities, and quality

maintenance, which add value to the product, shifts

along the consecutive links of logistic channels from

mainly technological to mainly consumer-oriented

aspects.

0044 At the central storage and distribution center, mass

and volume of units, protection against abuse (mech-

anical and thermal), and information are important.

0045 On the retail level, reliability, speed, and punctual-

ity of delivery and accurate compliance with the

ordered quality and quantity are most important.

Services of the preceding link in terms of continuity,

communication, flexibility, and claims handling

become more important.

0046 Consumers do not explicitly consider technology

and logistics, but instead focus on subjective attri-

butes, like sensorial aspects, convenience, nutritive

value, keepability, and waste disposal. Retailers

translate consumer desires into their own demands.

0047 Marketing activities are traditionally described in

terms of the four ’big Ps’ of product, place, price, and

promotion:

0048Product: the commodity that the market is looking

for, including purchase of the raw material, pro-

cessing and packaging, pollution, and politics.

0049Place: availability of the product in space and time

at consigned points of destination at the conveni-

ence of the consignee.

0050Price ultimately expresses the monetary value of

the product in the marketplace for the consumer,

but determines at the same time the span between

cost and revenue, the possible profit.

0051Promotion is a means of dealing with nonuniform

supply and demand. Customer service may be used

as an argument in promotion. On the whole, pro-

motion is strongly interrelated with the flexibility

of the logistic system to respond to discontinuities

in product flow.

Circumstantial factors can be designated the six

’small Ps’:

0052Purchase reaches forward to the raw material in

order to meet the requirements for processing in the

chain.

0053Processes are necessary to bring the primary prod-

uct into a state and shape to satisfy the different

requirements of handling along the logistic chain,

and of usage at the ultimate customer.

0054Package indicates not only mass or number, volume,

and shape in which the product satisfies the various

requirements in the logistic chain, but also the pro-

tecting, preserving, and presenting function, espe-

cially in the downstream links of the chain.

0055Pollution: environmental concern is becoming an

important aspect concerning the use of resources,

raw materials and energy, contributing to ozone

Logistics

Transformation

Goods transformation

Unitization

Aggregation/packaging

stacking

bundling

wrapping

Segregation

unstacking, etc.

Change

Appearance

Product transformation

Preservation/conditioning

drying

salting

sterilization

pasteurization

freezing

chilling

modified atmosphere

controlled atmosphere

Keepability

Quality life

Modularization

Standardization

Transport

Storage

Transfer

Transportation

Availability

in space and time

fig0003 Figure 3 Physical processes relevant for agrofood logistics.

5838 TRANSPORT LOGISTICS OF FOOD

depletion and the greenhouse effect. Also, product

losses and waste disposal (product and package

material) must be considered. Product pollution

by production, processing, and packaging has to

be excluded for reasons of public health.

0056 Politics interfere on different levels in the distri-

bution of perishable foodstuffs. Public health

authorities have developed a strong interest in

food processing and packaging, which has recently

been paralleled in the field of pollution. Also,

prices, conditions, and quality life (date marking)

are under political control all along the chain.

Regulations, guidelines, and standards for equip-

ment, processes, and labor conditions can greatly

affect the logic of logistic chains and, consequently,

the cost/quality balance, which demonstrates the

need for anticipating research and information.

0057 Public opinion: apart from political pressure, atti-

tudes and opinions determine the actions of the

consumer. Attentive retailers are aware of these

marketing aspects, and try to follow trends of

consumer preference.

Integration of Logistics and Marketing

0058 The need for efficient distribution of perishable prod-

ucts, i.e., to meet quality requirements at minimum

costs, has strengthened the need for integral planning

of logistic activities. Customer service, considered as

a goal variable and a constraint at the same time,

must be analyzed from a total distribution channel

perspective. This implies an integration of logistic and

marketing theories.

0059 Once the way is open to performing logistic oper-

ations in order to maximize customer service, the

issue of allocation of channel cost–benefits emerges.

This may give rise to alterations in distribution chan-

nel structures, resulting in forward or backward inte-

gration along the chain, and changes in distribution

channel power.

Budgeting and Accounting

0060 The growing need for the quantification of logistic

efforts has induced new developments in budgeting

and accounting, such as direct product costing (DPC)

and direct product profitability (DPP). In view of

stricter energy management and rising energy costs,

energy accountancy has been used to compare differ-

ent products with respect to their energy consump-

tion, including processing, handling, and packaging.

The same can be done for other cost elements, as long

as they are accounted separately.

0061 Integral Cost Accountancy The integral revenue-

expenditure concept can be recognized in cost

optimum production planning technique (COPPT),

which requires an accurate integral cost-accounting

system per unit of sales, including fixed and variable,

labor, energy and maintenance costs of processes and

equipment through all relevant links of the logistic

system.

0062Total cost analysis The formulation of a total cost

analysis is not without practical problems; the appre-

ciation of quality development and its balance against

capital costs represents a specific problem.

Modeling

0063Multiechelon models have been developed that inte-

grate the links of the distribution channel. Although

customer service is considered, in a narrow sense, as

out-of-stock and/or delivery time, these models offer

possibilities for modeling logistic operations, and

enable users to consider customer service as goal,

variable, and constraint.

The Physics of Physical Distribution

Logistics and Technological Processes

0064Two types of processes play important roles in logistic

chains–transformationandtransport.Transformation

brings the products into a state and shape in which

they can endure the rigors of the transport processes.

0065Goods transformation brings the products into a

form convenient for handling in the links of the

logistic chain.

0066Product transformation conditions the product

into a state in which it can comply with the require-

ments of quality at the point of destination.

Transformation

0067Goods transformation Agricultural products

become available in a given form, which is generally

not the most convenient for handling in a transport

chain. Small products have to be aggregated into

larger units; large products have to be segregated

into smaller units. Portioning, packing, and utiliza-

tion are common physical processes in agrofood

operations. For fluid products, the implementation

of these processes is simple compared to those for

solid products which cannot be fluidized. Mechaniza-

tion of goods transformation is easy to accomplish for

fluidizables. Solid products are more difficult to

handle. Mechanization closely follows human actions.

Sorting and grading are prerequisites for the forma-

tion of commercial units for the trade and, as such,

are part of customer service.

0068Goods transformation processes affect the appear-

ance of a product. Generally, an appearance has to

TRANSPORT LOGISTICS OF FOOD 5839

aggregate, to protect, and to present both the product

and information about the product. It must also fit

into the systems of transport, distribution, infor-

mation and, most important for perishables, of

conditioning.

0069 These requirements can lead to contradictions with

conventional solutions, and require special measures

with respect to conditioning, design of appearances,

and creation of the necessary external conditions. The

importance of the functions of an appearance varies

with the size of the unit. For the smaller units and

articles, the presentation function often outweighs the

protection, whereas the larger preparations mainly

serve aggregation and protection purposes. With the

larger size, the protective function includes facilita-

tion of conditioning, which switches from outside to

inside, e.g., pallet versus container (Table 2).

0070 Unitization The formation of units by aggregation

to larger appearances, or by segregation to smaller

ones, is summarized as unitization. In more detail,

stacking, bundling, wrapping, and their counter-

processes are concerned.

0071 Unitization is a necessary step in rationalizing

transport processes. Its interference with transform-

ation and conditioning processes should be fully

recognized. Methods and materials for unitization,

such as glueing, bundling by straps, wrapping in foils

or nets, by pallets, slip-sheets, slip-pallets, shipping

cases, and ballet boxes, isolate the product from ambi-

ent conditions by the dimensions and properties of the

material. Thus, more or less protection, e.g., resistance

against external conditioning, is built up by insulation

or permeability. Perforation of the separating covers

and application of pressure differences across the units

are means of controlling external conditioning.

0072 Modularization It is obvious that a coordinated

relationship between the dimensions of appearances

greatly rationalizes handling, utilization of storage,

and transportation space and use of equipment. An

early example is the unicube concept, developed in

The Netherlands, c. 1965. In later years, the National

Materials Handling Bureau of Australia (c. 1980), the

International Organization for Standardization (ISO)

(in the early 1980s) and the US–Canadian Modular-

ization-Unitization-Metrification Project pursued the

same line.

0073A problem rises from the choice of the module. The

early adoption of the manload as the module (1968)

has led to diverging developments in unit loads,

leading to the continuation of the problem in the

domain of transport units. The result is a very unsatis-

factory situation of competing unit loads and incom-

patible transport units.

0074Standardization Standardization of mass and di-

mensions is necessary for the operation of an efficient

logistic system. Good examples are the Australian

and the North American approach. Unfortunately,

Europe cannot adopt a uniform, simple system as

long as industries adhere to two standard unit loads.

In spite of the recommendation of the ISO to prefer

the 1200 1000 mm unit as maximum plan view

size (MPVS) or gross unit load size (GULS) and

central modular standard, some industries stick to

1200 800 mm units, which makes the manload

(600 400 mm) the central module on a lower level

of aggregation and means a loss of flexibility of

configuration within the unit load.

0075Modeling Goods transformation process modeling

has to start from the dimensions of the articles that

have to be accommodated in the subsequent aggre-

gated unit, taking account of the necessary toler-

ances for the design, stacking, deformation, and

conditioning.

0076Design systems The design of modular packaging

is greatly facilitated by the existence of transport

package and loading pattern selection tables and

palettizing charts, as well as graphical and graphical-

plus-calculator design systems. Comprehensive com-

puter programs are available to evaluate all factors

influencing the basic package design. They are con-

sulted to determine all three dimensions of the unit

tbl0002 Table 2 Thermophysical properties of appearances; results of goods transformation

Domain Mass (kg) Diameter (m) Cooling time (h)

Overtemperature (



Product 0.1 0.05 0.2 0.2

Article 0.5 0.1 2.0 1.0

Manload 15 0.3 18 6.0

Unit load 500 1.0 180 Thermal explosion

Transport unit 7500 2.5 900 Thermal explosion

Storage unit 30 000 5.0 3600 Thermal explosion

With external conditioning.

Heat generation 100 W t

1

5840 TRANSPORT LOGISTICS OF FOOD

load and the manloads which form it. Thus a means is

provided to produce an extensive list of options and

to evaluate the various compromises rated against the

factors contained in the input data. Computer pro-

grams also allow for the use of average industry al-

lowances for many factors involved, which reduces

the preparation work. With regard to conditioning,

the thermophysical properties of product and pack-

age have to be considered, as well as penetration by

the conditioning medium, which is generally air.

0077 Product transformation By various processes, agro-

food products can be transformed into a state in

which they can meet the requirements of a given

transport process within given limits of quality. The

choice is between chilling, freezing, pasteurization,

sterilization, salting, and drying, in order of increas-

ing keeping times and decreasing approximation

to the fresh product. Food preservation technology

is thus linked directly to agrofood logistics. Irradi-

ation, modified-atmosphere (MA) and controlled-

atmosphere (CA) treatments also transform the

product with respect to its keepability. Generally,

these techniques require close temperature control as

well. There is also a link to packaging with respect to

heat and mass transfer. Refer to individual processes.

0078 Quality life Keeping time or quality life, as depend-

ent on the environmental conditions around the

product, limits the throughput time of products in

the logistic chain. Parts of the total quality life are

often considered separately, as storage life (the first

part) or as shelf-life (the last part) of the total

economic quality life.

0079 The quality life of a product is limited by the rate of

quality loss or deterioration and the imposed limita-

tions. A difference can be made between high-quality

life and practical quality life; these differ in the degree

of change of characteristic properties of the product.

Development of quality with time can be attributed to

different principal processes of a physical, chemical,

or biological nature, the rates of which are dependent

on environmental factors such as temperature, water

vapor concentration or pressure deficit, and atmos-

phere composition. (See Storage Stability: Mechan-

isms of Degradation; Parameters Affecting Storage

Stability; Shelf-life Testing.)

0080 These quality-affecting processes act in different

ways on two main groups of foodstuffs:

0081 Dead products: subject to (bio)chemical and

microbiological processes.

0082 Living produce: in addition exhibiting biological

processes, dissimilation with O

CO

conversion

and heat production.

N.B: fermentation and microbiological growth can

also cause CO

and heat production. Both groups

can be divided into two subgroups:

0083Those in need of a process of maturation to reach

maximum consumer quality: red meats, cheeses,

fresh fruits (banana, peach, pear, plum).

0084Those which start commercial life at maximum

consumer quality: sterilized, pasteurized, and

frozen products, white meats, fish, fresh vege-

tables, mushrooms, bakery products, prepared

meals.

Group A products, represented by c. 16% of the food

basket, need controlled holding times and conditions

to reach maximum quality. From then onwards, they

require limited throughflow times in the logistic

chains, adjusted to the environmental conditions for

tolerable quality loss, as do group B products.

0085Quality models The necessity for quality models to

be incorporated into logistic models results from the

great number of alternative logistic processes which

have to be evaluated in the design of distribution

chains. Quality loss of food is largely determined by

the cumulative effect of the environmental conditions

throughout the handling history of the product. The

simple rules of additivity and exchangeability are

obeyed better the less the product is processed.

0086It is impractical and expensive to conduct product

spoilage tests for all possible scenarios. Mathematical

models can be chosen after verification by simple

experiments on the basis of statistical tests on the

lack of fit against experimental error. By measuring

and modeling deterioration reactions, quantitative

data are collected, and models as well as model

parameters can be generated. For integration into

process or logistic models, quality models for the

influence of environmental factors should comply

with the following, in the order presented:

0087The broadest possible application on the processes

considered.

0088Appropriate consideration of the mechanism of

the reaction.

0089Simplicity of determination of parameters, and

application.

0090The smallest deviations from experimental values.

0091No discontinuities.

0092These models may be based on the time-course of

specific components or properties from physical,

chemical, or sensorial analysis or, in the absence of

objective information, on expert judgment, always

keeping in mind the possibility of adjustment of the

quality scale of the chosen model.

TRANSPORT LOGISTICS OF FOOD 5841

0093 Zero or first-order reaction mechanisms can

cover practically all deterioration processes re-

gardless of their nature. Arrhenius-type relationships

satisfactorily describe the influences of temperature;

linear, hyperbolic, or squareroot relationships re-

quire the same type of parameters. For other envir-

onmental factors, more direct relationships to the

driving force exist. For the combined influence of

temperature and gas concentration, special models

have to be derived from specific experimental re-

search.

0094 Combined models For temperature-dependent de-

terioration processes, combined heat-transfer models

are most useful. They allow prediction of the effects

of management decisions on quality life of condi-

tioned products, especially on the shelf-life. Better

protection during transport processes, by reducing

the time–temperature load, can be balanced against

lower temperature levels or shorter flow-times in one

or more links of the chain.

0095 It is obvious that the performance of deterioration

tests for all possible scenarios is highly impractical

and expensive. Mathematical modeling, computer-

ized on the basis of experimentally established

parameters, and a few validation experiments can

perform the necessary sensitivity analyses and assist

in finding the optimal operational conditions.

0096 Chain reactions A product passing through a logis-

tic chain generally encounters a sequence of environ-

mental conditions. The final state when leaving the

nth link of the chain is decisive. If the prerequisites of

additivity and exchangeability are fulfilled, the result

of the chain reaction can be described on the basis

of average time and temperature conditions by a

sequence of ideal reactors.

0097Temperature and time distributions Average time

and temperature provide only a crude way of describ-

ing the flow of goods and the influence of environ-

mental conditions in the chain. Statistical mathematics

offers a way of dealing with the time and temperature

distributions encountered in practice. The Weibull

distribution appears to yield the most general model

for time and temperature distributions in the links

of logistic chains. The background for the ready

modeling of logistic distributions by the Weibull func-

tion is given by the fact that the minimum value

is given by a solid physical condition, whereas the

maximum is open to stochastic influences. Two par-

ameters for scale and shape allow for the modeling

of a wide range of practical situations, from plug

flow to ideal mixing, with all possible intermediate

situations.

0098Arbitrary distributions A more direct approach can

be based on the fractional distribution of time and

conditions in the links of the chain. The stepwise

calculation of the final quality distribution after a

number of links, from the distributions of time and

temperature in the links, and the initial quality distri-

bution, can easily be computerized. This approach

presents a means of balancing profits of quality

retention against expenditure for throughflow time

and improvement of conditions, if the cost–revenue

analysis is done in appropriate figures.

0099Standardization As in goods transformation, prod-

uct transformation also presents reasons for stand-

ardization in terms of quality life, temperature

sensitivity and, as a consequence, keeping equipment,

storage facilities, as well as transport vehicles and

transfer processes. Products can be categorized

according to keeping temperatures and quality life at

tbl0003 Table 3 Categories of refrigerated foodstuffs

Code Reference temperatureT

ref

(



C) Temperature increment B (1/K) Examples

DF 18 Positive/negative Regulations

F 12 Deep-frozen, frozen products

C04 þ4 Negative Small meat portions, ready-to-eat vegetables, pasteurized

meals, salads, large meat portions, sterilized meals, dairy

products

C07 þ7

F00 0 Positive Leafy vegetables, berries, pears

F04 þ4 Apples, oranges, potatoes

F07 þ7 Green beans, subtropical fruits

F10 þ10 Avocado, mango, subtropical, and tropical produce

F13 þ13 Bananas, pineapple, tropical produce

Quality life at temperature T:t¼ t

ref

exp[B(T  T

ref

)].

Temperatures and commodities quoted are arbitrary examples. They can vary by national regulation or specific product requirements. From Meffert

HFTh (1990b) Chilled foods in the market place. In: Processing and Quality of Foods, vol. 3. London: Elsevier Applied Science, with permission.

5842 TRANSPORT LOGISTICS OF FOOD

a reference temperature and temperature sensitivity,

as shown in Tables 3 and 4.

010 0 Standardization in such a way facilitates the design

of distribution processes in existing chains and of new

operations, especially if paralleled by a standardiza-

tion of storage and transport equipment, and transfer

processes, in terms of operational performance, e.g.,

temperature maintenance by a degree of thermal

protection derived from the nonaccomplished tem-

perature fraction. Existing classification and stand-

ardization of these types of equipment and processes

do not attempt to enter this problem area. ISO, ATP,

and Lloyd’sclassification are based on technical rather

than technological performance characteristics.

010 1 Recent European Community and national legisla-

tion concerning the temperature of frozen and chilled

products may create a need for a more operational

approach to product, equipment, and process classifi-

cation, or even standardization, as explained above.

Transport ¼ Storage–Transfer–Transportation

0102 The second, more genuine logistic process is that of

transport. Generally, the transport in a logistic chain

involves mass, energy, and information (M–E–I).

Mass flow downstream and information flow up-

and downstream are easily recognized. Less obvious

is the transport of energy. For refrigerated products,

this aspect is closely related to product transform-

ation and conditioning. Attention is required for

reasons of economy in quality protection.

0103 Mass The most apparent transport process is that of

mass. However, as agrofood products are mostly in

the category of high-volume goods (load density

lower than 500 kg m

3

), it is more appropriate to

treat transport in agrofood logistics in terms of

volume. Figure 4 depicts a scheme of the mass flow

in distribution chains for refrigerated foodstuffs.

0104All activities of moving goods between origin and

destination can be understood as transport, storage

being transportation with zero speed. Generally, the

goods pass a number of storage and transportation

links on their way through the chain. All links are

interfaced by transfer or transshipment processes.

0105As a rule, a reduction of the links in the logistic

chain reduces cost and losses; in addition, it saves

time. This pleads for careful consideration of the

necessity of the links, which can lead to integration

of processes, such as product transformation by

chilling or freezing, into the transportation link. In-

transit treatments, thermal or by gas injection, are

also practiced for disinfection or disinfestation.

0106The second important rule is the rationalization,

for time and cost reasons, of the transfer process,

which links transport closely to goods transform-

ation.

0107The maintenance of the established condition of

the product is a specific task in the transport chain

of agrofood products, in addition to the general task

of conveyance.

0108Interrelationships with transformation and condition-

ing Modular coordination, i.e., dimensional cap-

ability of appearances and equipment as elements of

a system, is a prerequisite for rationalization of trans-

port processes, and as such subject to standardiza-

tion. Elements of a covering system for modular

coordination are represented by ISO standards on

manloads, unit loads, and transport units in ISO

668–1968, 3676–1983, 6780–1988, 3394–1984,

tbl00 04 Table 4 Time–temperaturematrixofkeepabilitycharacteristics

DenominationTime,t

ref

(days)Temperatureincrement,B(1/K)

< 0.05Low0.05^0.15Medium0.15^0.25High > 0.25Extrasensitive

Chilledproduct(categoryCO4)

Extra short < 3 Kitchen-ready vegetables

Leeks Cabbage Carrots

Very short 3–7 Minced beef Poultry Pork

Short 7–14 Beef slices Pasteurized milk

Medium 14–30 Beef joints (CO

-packed)

Long > 30 Lamb carcass (cryo-vac)

Frozen product (category DF)

Extra short < 30

Very short 30–100 Cooked meals Cured pork

Short 100–200 Seafood

Medium 200–400 Cream Carcass meat Vegetables

Long > 400 Butter, lamb Raw dough, poultry Green peas, fruit

Examplesaregivenfortwocategoriesfrom Table 2.

From Meffert HFTh (1990c) Quality development of foodstuffs under time–temperature conditions in cold chains. In: Progress in the Science and Technology

of Refrigeration in Food Engineering. Paris: International Institute of Refrigeration, with permission.

TRANSPORT LOGISTICS OF FOOD 5843

1496/2–1988. Unfortunately, the system is not prac-

tical for conditioned units, because of the space

requirements for insulation, air circulation, and the

necessary equipment for conditioning. The Australian

Standards represent a more logical coordination.

Revision of the dimensions of the transport unit for

better compatibility with unit loads has so far met

much opposition. Elements for a better-fitting system

appear in European and US traffic regulations, and in

the standards of the European Normalization Centre

(CEN) for removable vehicle bodies (swap-bodies),

allowing extra width for conditioned road vehicles.

0109 For perishable products, conditioning is necessary

to keep the quality loss in logistic chains within a

preset span. Distribution of time and conditions, the

most important being the temperature, are the

governing process variables.

0110 Methods of unitization generally interfere with

conditioning processes. Pallets, slip-sheets, slip-pallet,

etc., and wrappings influence the distribution of con-

ditioning air. Perforations and build-up of pressure

differences around the unit promote air penetration.

This must be considered in the choice of tolerances

which make the modular system work. The larger the

unit handled, the shorter are the transfer times per

mass between the links of the transport chain. Shorter

times of exposure, together with a small surface-to-

volume ratio, improve the thermal protection.

Storage

0111Facilities for storage in logistic chains are destined to

buffer discontinuities of the product flow between

supply and demand. They can be subdivided into

types differing in task, size, and operational condi-

tions:

0112Primary or production stores. Storage space at the

production site serves as a buffer volume between

the discontinuities of the inflow from the produc-

tion process and the outflow of products to sec-

ondary stores. Residence times are short. The band

of conditions cannot be kept small because of the

high turnover. For unitized products, row storage

on pallets is preferred.

0113Secondary or central stores. In the case of seasonal

production, central stores are loaded within a

Commodity

Level

Fish

Catching

Slaughtering Slaughtering Collecting Collecting

Processing Processing Processing Processing

Cold store

Port cold

store

Catering:

refrigerators,

display cabinets

Retail:

back-up stores,

display cabinets

Home refrigerators

Consumers

Central

store

Distribution/wholesalers, cold store

Cold store Cold store Cold store

Meat Dairy Fruit/vegetable Imports

Port cold

store

(T)

(T) (T)

(T)

(T) (T) (T) (T)

(T)

fig0004 Figure 4 Principal structure of distribution chains for refrigerated foodstuffs (T), transportation and transfers. Note that for products

with extremely or very short quality life, the distribution link is cut short by direct links between processing and retail/catering. Adapted

from Nowotny S (1988) Computer-modeling of cold chain systems. In: Cold Chains in Economic Perspective, Paris: International Institute

of Refrigeration.

5844 TRANSPORT LOGISTICS OF FOOD

short period, but emptied slowly. Volume-saving

block storage of unit loads or transport units,

if necessary with supporting frames, minimizes

investment in conditioned space. The principle of

first-in–first-out (FIFO) cannot be fully realized

because of the limited accessibility of the units.

0114 Nonseasonal products are supposed to pass

central stores rapidly to keep investment in space

and product low. Owing to the high turnover rate,

the FIFO principle cannot be strictly observed,

but through-flow racks, gravity or mechanically

driven, can help.

0115 Storage conditions are optimized within a

narrow band of environmental factors. Residence

times vary according to the type of product, but

tend to be a substantial part of quality life.

0116 Tertiary or distribution stores. Distribution stores

are mere turnover facilities designed for rapid

handling of flows of various products. Again the

FIFO principle cannot be applied; mixing of

products of different age is usual. Incomplete

unit loads remain longer in store than complete

ones.

0117 Rack storage, manually or automatically oper-

ated for separate accessibility of units, is fre-

quently used, in spite of the large loss of space.

Arrival and departure areas are separated, and

commissioning areas are provided, mostly with

only partial protection against external condi-

tions. Environmental conditions are not optimal,

but residence times are comparably short. In par-

tially protected areas, a high flow rate of products

must keep the ambient load low.

0118 Quarternary stores, retail cabinets. At the retail-

ers, display cabinets of fractions of a cubic meter

shelf volume per meter present the product to the

consumer. Because of the great influence of the

ambient conditions in the shop, and the fact that

the product is handled in articles rather than man-

loads, conditioning is possible only within a broad

band. This restriction must be compensated for

by extremely short, carefully watched residence

times, which also keep at bay the comparatively

high costs per volume per time in this link.

0119For the reception of a discontinuous flow of

goods at the retailer, a conditioned back-up store

can form a buffer. This is kept as small as possible.

Row storage is used. Conditioning is problematic,

owing to the high turnover rate; thus residence

times have to be kept at a minimum, depending

on consumers’ buying attitudes.

0120Standardization Generally, storage facilities up to

tertiary level are built to customer specifications, in-

cluding layout for unit loads and, in some cases, even

whole transport units. Standards apply for technical

equipment. Exceptions are the standard cold stores in

East Europe, which are classified for layout, size, and

storage conditions.

0121The usage of space by different stacking methods

can be given approximately as:

0122Block storage 100%

0123Movable racks 80–90%

0124Row storage 60–80%

0125Rack storage 50–60%

depending on the height. Additional space has to be

provided, according to the equipment, for the con-

veyance of goods.

0126Heat load from ambient and air circulation

performance, which determine the quality of condi-

tioning, are chosen for economic considerations, in-

cluding losses of mass and quality. Small storage and

retail cabinets are built serially. Detailed general

standards exist only for refrigerated display cabinets

(ISO 1992/1–8; ISO 5160/1–2).

Transfer

0127Processes of cargo transfer or transshipment are char-

acterized by transfer times and degree of protection

against ambient conditions. Cargoes are handled in

units from manloads to transport units, with various

types of equipment from manhandling to large fork-

lift trucks or cranes for whole transport units. Fortu-

nately, the rate of cargo transfer and the degree of

protection increase with the size of the unit, and costs

decrease per unit of volume (Table 5).

tbl0005 Table 5 Cargo transfer in large and small units: time, protection, cost

Operation Transfer time (min) Relative cost (%)

Long-haul truck,

18 pallets of 720 kg, with lift truck Load/unload, 15 100

560 manloads of 28 kg, belt conveyor Load/unload, 84 140

Delivery truck, 16 deliveries of 20 manloads of 15 kg

On pallet Load, 13; unload, 16  5 100

Per manload 37 16  18 250

TRANSPORT LOGISTICS OF FOOD 5845

0128 Flow times in the transfer links are determined by

the rate of transfer and the volume to be transferred.

The need to condition the transfer area depends on the

external climate. The degree of protection in this case

is a function of time.

0129 Standardization The standardization of appear-

ances in transport chains has led to a standardization

of transfer equipment in terms of speed, volume, and

mass that can be handled (conveyors, trucks, cranes).

Transportation

0130 Means of transportation exist for the land, road and

rail, sea and air modes. The intermodal container

has united these and closed the protected-chain

operation. On a regional scale, the removable body

or swap-body serves the same purpose.

0131 Road vehicles account for the largest part of the

transportation of agrofood products. On a national

basis in the EC, up to 90% of the flow of foodstuffs is

by road transport that must conform to traffic regu-

lations; this has resulted, practically, in standardiza-

tion according to size and mass. Containers and

removable bodies (swap-bodies) comply with strin-

gent ISO standards for external and internal dimen-

sions. Conditioned road vehicles and swap-bodies

can comply better with ISO unit loads than do ISO

containers. For both types of vehicle, performance is

regulated. Residence times are close to transit times,

and almost uniform, except for delivery runs, which

are mostly short.

0132 Railcars are larger and comply with standards of

the railroad administrations, not necessarily with unit

load standards. Ships are built to customers’ or

builders’ standards, and aircraft largely to builders’

standards, which include compliance with unit load,

pallet, and/or container regulations. Unfortunately,

air cargo unit load devices other than air/surface con-

tainers are not part of the ISO modular system.

0133 Conditioning depends on the specifications of the

customer and the performance of the builder. In sea

carriage, narrow bands of conditions are normally

realized, much less in air transportation, which leans

on the advantage of short transit times.

0134 Residence times under transit conditions are

mostly close to transit times, because waiting times

are under pressure in all links of the chain. On short

distances by rail, waterways, and air, waiting times

can be considerable, depending on schedules. The

speeds of land and sea transportation are practically

the same, between 30 and 60 km h

1

(considerably

less on inland waterways), but transit times are in fact

restricted by the frequency of departures for inter-

modal combined transportation, and by regulations

concerning the active time of drivers for the road leg.

0135Standardization Standardization of means of trans-

portation is traditionally concerned with external

aspects. Only recently has the principle of vehicle

design around the cargo been introduced by allowing

double-pallet-wide, conditioned road vehicles in the

EC and the USA. ISO is also paying attention to this

aspect by standardizing the minimum internal dimen-

sions of thermal containers (ISO 1496/2–1988).

Modular coordination with unit loads has not been

attained yet.

0136Standards for containers (ISO) and regulations for

road vehicles and railcars (Economic Commission for

Europe) exist for thermal insulation and refrigeration

power, but not for operational characteristics, such as

the temperature band.

0137Standardization of road vehicles, railcars, ships,

and aircrafts as carriers is linked to the external di-

mensions of unit loads or transport units to be accom-

modated within the limits given by the traffic system,

by law or by convention.

0138Degree of protection For all conditioning processes

in the transport chain, the degree of protection

against temperature rise can be defined by means of

the nonaccomplished temperature rise of the product

as the fraction of the difference from the target or

reference temperature to ambient.

0139For refrigerated spaces, the quotient-heat load

factor over air circulation is a specific operational

criterion of performance. For the evaluation of the

conditioning process, the influence of air distribution

and product heat load can be introduced by an

empirical coefficient.

0140For transient processes, such as the temperature rise

during cargo transfer, transient heat transfer theory

offers suitable models for the estimation of the degree

of thermal protection, which now depends on time.

0141Energy If the accumulated energy per conveyed unit

of mass by the processes in the chain is recognized as

transported energy, the concept of energy transport in

distribution chains becomes meaningful, especially if

the energy input is accounted for. Particularly for

perishable products which have been subjected to a

product transformation, the energy accumulated by

the transformation process and by the subsequent

conditioning for protection against quality loss

makes the quality of energy management visible. A

very basic approach considers the total energy input

for primary production, processing, and handling, as

well as for auxiliary materials. More chain-relevant

information takes account of chain processes only

(Tables 6 and 7).

0142Low degrees of protection in the links of a chain

mean great deviations from the target temperature

5846 TRANSPORT LOGISTICS OF FOOD

and bad energy management, leading to additional

costs of energy to restore conditions and quality loss.

0143 Finally, the economic consequences of distribution

processes boil down to cost accounts (Table 8).

0144 Information Transport processes are controlled by

the demands of the market. In order to realize just-in-

time (JIT) delivery, the signal for replenishment has

to be sent in due time, allowing for the necessary

time for the order cycle. A scheme of the information

flow in a cold-chain system with computer-assisted

guidance, management, and supervision is shown in

Figure 5.

0145 Data acquisition and processing Upstream commu-

nication along logistic chains mostly concerns the

order procedure, which has to be initiated by reliable

information from the outlets. Because the signal has

to be given in advance of stock depletion, a model is

needed to predict the necessary JIT delivery. Further

information upstream can be required to redirect the

goods flow in case of unforeseen developments of the

market. Downstream communication should contain

information on the product and its peculiarities, qual-

ity life and reference conditions (date marking). More

relevant are remaining quality life, required condi-

tions, and handling recommendations. These should

be communicated in advance of the goods. They must

be matched by information on equipment and condi-

tions in the links. Standardization of information is

helpful to reduce variations and mistakes, and to

speed up the information flow. Bar-coding and scan-

ning at the interfaces backed by a computerized

inventory management system is a powerful means

of quality management of an agrologistical chain of

operations. Its introduction again requires standard-

ization of information and procedures, and must be

the subject of a careful cost–benefit analysis.

0146Processing of these data for operational purposes is

only possible by powerful computer systems with

specific software. In the preparatory phase, for the

establishment of the necessary tools, even more com-

puting capacity is needed to evaluate possible alterna-

tive chains and networks by modeling calculations

and simulation in a reasonable time. It is in this

application that large computer capacities and high

calculation speeds are required.

0147Inventory management In many cases, the conven-

tional FIFO concept is not able to satisfy the justified

quality requirements of the customer. Limitation of

throughflow time deals with one aspect of quality

management, limitation of temperature with another,

whereas only the combination of the two can yield

the appropriate measures. Inventory management,

therefore, should be based on information about the

time–temperature load on the product rather than

on time-based information alone (shortest remaining

shelf-life instead of FIFO as a management criterion).

tbl0006 Table 6 Energy consumption in distribution chains of refrigerated foodstuffs

Link Frozen Chilled

Energyrate

(W t

1

)

Time (days) Energyaccumulated

(kJkg

1

)

Energyrate

(W t

1

)

Time (days) Energy accumulated

(kJ kg

1

)

Product transfer 400 40–120

Central store 13–60 165 100–850 50–125 5–12

Transportation

1 600 570

Distribution store 30–120 46 120–480 100–250 1 9–22

Transportation

1 850 1 800

Retail cabinet c. 2000 10 c. 1700 c. 10 000 1 c. 860

Domestic refrigerator c. 500 23 c. 1000 1500–3000 1 125–250

Total 246 4850–5850 4 1834–1979

20.5 t  500 km. Frozen, þ15%; chilled, þ10%.

5.6 t  200 km. Frozen, þ15%; chilled, þ10%.

Adapted from IIF/IIR (1980).

tbl0007 Table 7 Fuel energy inputs for transportation

Means of transportation Load capacity

(tonnes)

MJ km

1

MJ t

1

Fullyloaded

Empty Full

Ship 49 000 0.127

Rail 1000 0.36

Truck and trailer

Rural 20.6 12.1 15.3 0.74

Urban 20.6 17.1 26.9 1.31

Truck

Rural 5.6 8.3 9.8 1.75

Urban 5.6 12.1 14.5 2.59

Van

Rural 0.4 4.3 4.8 12.0

Urban 0.4 6.7 7.3 18.3

From IIF/IIR (1980).

TRANSPORT LOGISTICS OF FOOD 5847