II. CONCEPTS AND DEFINITIONS USED IN FOOD BALANCE SHEETS

1. COMMODITY COVERAGE

As already indicated, all potentially edible commodities should, in principle, be taken into account in preparing food balance sheets regardless of whether they are actually eaten or used for non-food purposes. The definition of a complete list of potentially edible commodities presents virtually insurmountable difficulties - both conceptual and statistical. For practical purposes, therefore, a pragmatic list of commodities will have to be adopted. Generally, food balance sheets are constructed for primary crops, livestock and fish commodities up to the first stage of processing in the case of crops and to the second (and sometimes the third) stage of processing in the case of livestock and fish products. The reason for the restriction on the higher stages of processing is the difficulty in obtaining data for all the varied forms of processed products, and even more difficult, in tracing the components of the processed composite products. The following list of commodities and their classification into major food groups is proposed for food balance sheet purposes. It should, however, be adjusted according to the availability of commodities in a given country.

Under each item, primary as well as derived commodities, up to the first stage of processing, are considered as appropriate, e.g. wheat, wheat flour (instead of bread), or milk, butter, ghee, skim milk, cheese (from whole milk and skim milk), dried and condensed milk (from whole milk or skim milk).

2. SUPPLY AND UTILIZATION ELEMENTS

1. Production. For primary commodities, production should relate to the total domestic production whether inside or outside the agricultural sector, i.e. including non-commercial production and production in kitchen gardens. Unless otherwise indicated, production is reported at the farm level for primary crops (i.e. excluding harvesting losses for crops) and livestock items and in terms of live weight (i.e. the actual ex-water weight of the catch at the time of capture) for primary fish items. Production of processed commodities relates to the total output of the commodity at the manufacture level (i.e. it comprises output from domestic and imported raw materials of originating products). Reporting units are chosen accordingly, e.g. cereals are reported in terms of grains and paddy rice. As a general rule, all data on meat are expressed in terms of carcass weight. Usually the data on production relate to that which takes place during the reference period. However, production of certain crops may relate to the harvest of the year preceding the utilization period if harvesting takes place late in the year. In such instances, the production of a given year largely moves into consumption in the subsequent year.

In the sample Form II of the food balance sheet, located at the end of this document, a distinction is made between "output" and "input". The production of primary as well as of derived products is reported under "output". For derived commodities, the amounts of the originating commodity that are required for obtaining the output of the derived product are indicated under "input", and are expressed in terms of the originating commodity.

2. Changes in Stocks. In principle, this comprises changes in stocks occurring during the reference period at all levels from production to the retail stage, i.e. it comprises changes in government stocks, in stocks with manufacturers, importers, exporters, other wholesale and retail merchants, transport and storage enterprises, and in stocks on farms. In practice, though, the information available often relates only to stocks held by governments, and even this is, for a variety of reasons, not available for a number of countries and important commodities. It is because of this that food balance sheets are usually prepared as an average for several years as this is believed to reduce the degree of inaccuracy contributed by the absence of information on stocks. Increases in stocks of a commodity reduce the availability for domestic utilization. They are therefore indicated by the - sign and decreases in stocks by the + sign since they increase the available supply. In the absence of information on opening and closing stocks, changes in stocks are also used for shifting production from the calendar year in which it is harvested to the year in which it enters domestic utilization or is exported.

3. Gross Imports. In principle, this covers all movements of the commodity in question into the country as well as of commodities derived therefrom and not separately included in the food balance sheet. It, therefore, includes commercial trade, food aid granted on specific terms, donated quantities, and estimates of unrecorded trade. As a general rule, figures are reported in terms of net weight, i.e. excluding the weight of the container.

4. Supply. There are various possible ways to define "supply" and, in fact, various concepts are in use. The elements involved are production, imports, exports and changes in stocks (increases or decreases). There is no doubt that production, imports, and decreases in stocks are genuine supply elements. Exports and increases in stocks might, however, be considered to be utilization elements. Accordingly, the following possibilities exist for defining "supply".

(a) Production + imports + decrease in stocks = total supply.

(b) Production + imports + changes in stocks (decrease or increase) = supply

available for export and domestic utilization.

(c) Production + imports - exports + changes in stocks (decrease or increase) =

supply for domestic utilization.

Over the years, FAO has used all three concepts of "supply". In recent years concept (c) has been adopted when preparing and publishing food balance sheets in order to identify the quantity of the commodity in question which is available for utilization within the country.

5. Gross Exports. In principle, this covers all movements of the commodity in question out of the country during the reference period. The conditions specified for gross imports, under 3. above, apply also to exports by analogy. A number of commodities are processed into food and feed items. Therefore, there is a need to identify the components of the processed material exported in order to arrive at a correct picture of supplies for food and feed in a given time-reference period.

6. Feed. This comprises amounts of the commodity in question and of edible commodities derived therefrom not shown separately in the food balance sheet (e.g. dried cassava, but excluding by-products, such as bran and oilcakes) that are fed to livestock during the reference period, whether domestically produced or imported.

7. Seed. In principle, this comprises all amounts of the commodity in question used during the reference period for reproductive purposes, such as seed, sugar cane planted, eggs for hatching and fish for bait, whether domestically produced or imported. Whenever official data are not available, seed figures can be estimated either as a percentage of production (e.g. eggs for hatching) or by multiplying a seed rate with the area under the crop of the subsequent year. In those cases where part of the crop is harvested green (e.g. cereals for direct feed or silage, green peas, green beans) an adjustment must be made for this area. Usually, the average amount of seed needed per hectare planted in any given country, does not greatly vary from year to year.

8. Food Manufacture. The amounts of the commodity in question used during the reference period for manufacture of processed commodities for which separate entries are provided in the food balance sheet either in the same or in another food group (e.g. sugar, fats and oils, alcoholic beverages) are shown under the column Food Manufacture. Quantities of the commodity in question used for manufacture for non-food purposes, e.g. oil for soap, are shown under the element Other Uses. The processed products do not always appear in the same food group. While oilseeds are shown under the aggregate Oilcrops, the respective oil is shown under the Vegetable Oils group; similarly, skim milk is in the Milk group, while butter is shown under the aggregate Animal Fats. Barley, maize, millet and sorghum are in the Cereals group, while beer made from these cereals is shown under the Alcoholic Beverages group. The same principle applies for grapes and wine.

9. Waste. This comprises the amounts of the commodity in question and of the commodities derived therefrom not further pursued in the food balance sheets, lost at all stages between the level at which production is recorded and the household, i.e. losses during storage and transportation. Losses occurring during the pre-harvest and harvesting stages are excluded (see note on "Production").

Technical losses occurring during the transformation of the primary commodities into processed products are taken into account in the assessment of respective extraction/conversion rates.

Post-harvest losses in most countries are substantial owing to the fact that most of the grain production is retained on the farm so as to provide sufficient quantities to last from one harvest to the next. Farm storage facilities in many countries tend to be primitive and inadequately protected from the natural competitors of man for food. Losses become even more serious in countries where agricultural products reach consumers in urban areas after passing through several marketing stages. In fact, one of the major causes of food losses in some countries is the lack of adequate marketing systems and organization. Much food remains unsold because of the imbalances of supply and demand. This is particularly true of perishable foods, such as fresh fruit and vegetables. Post-harvest losses of fruit and vegetables of between 25 and 40 percent occur in many countries, mainly as a result of untimely harvesting and improper packing and/or transport.

The waste of both edible and inedible parts of the commodity occurring in the household, e.g. in the kitchen, also is excluded.

10. Other uses. In order not to distort the picture of the national food pattern, quantities of the commodity in question, consumed mainly by tourists, are included here (see also "12. Per Caput Supply") as well as the amounts of the commodity in question used during the reference period for the manufacture for non-food purposes (e.g. oil for soap). Also statistical discrepancies are included here. They are defined as an inequality between supply and utilization statistics. The food balance sheets are compiled using statistics from various sources. Where no official data are available, other sources of information may be used.

Many of the supply and utilization elements compiled from available information will not balance. Bringing together data from different sources would almost always result in an imbalance. Beyond the problem of data sources, imbalances usually fall into one of the following three situations: those occurring mainly in developed countries where there is no shortage of official statistics but the information is not internally consistent; cases in which the data are consistent but incomplete; and situations where data are both inconsistent and incomplete.

11. Food. This comprises the amounts of the commodity in question and of any commodities derived therefrom not further pursued in the food balance sheet that are available for human consumption during the reference period. The element food of maize, for example, comprises the amount of maize, maize meal and any other products derived therefrom, like cornflakes, available for human consumption.

The food element for vegetables comprises the amount of fresh vegetables, canned vegetables, and any other products derived therefrom. But the element food of milk relates to the amounts of milk available for human consumption as milk during the reference period, but not as butter, cheese or any other milk product provided for separately in the food balance sheet.

It is important to note that the quantities of food available for human consumption, as estimated in the food balance sheet, reflect only the quantities reaching the consumer. The amount of food actually consumed may be lower than the quantity shown in the food balance sheet depending on the degree of losses of edible food and nutrients in the household, e.g. during storage, in preparation and cooking (which affect vitamins and minerals to a greater extent than they do calories, protein and fat), as plate-waste, or quantities fed to domestic animals and pets, or thrown away.

12. Per Caput Supply. Under this heading estimates are provided of per caput food supplies available for human consumption during the reference period in terms of quantity, caloric value, and protein and fat content. Per caput food supplies in terms of quantity are given both in kilograms per year and grams per day, calorie supplies are expressed in kilo-calories (calories) per day, while supplies of protein and fat are provided in grams per day. It is proposed to retain the traditional unit of calories for the time being until such time as the proposed "kilojoule" gains wider acceptance and understanding (1 calorie = 4.19 kilojoules).

Per caput supplies in terms of quantity are derived from the total supplies available for human consumption by dividing the quantities of the food element by the total population actually partaking of the food supplies during the reference period, i.e. the present in-area (de facto) population within the present geographical boundaries of the country in question at the mid-point of the reference period. Accordingly, nationals living abroad during the reference period are excluded but foreigners living in the country are included. Adjustments should be made wherever possible for part-time presence or absence, such as temporary migrants and tourists, and for special population groups not partaking of the national food supply such as aborigines living under subsistence conditions (if it has not been possible to include subsistence production in the food balance sheets) and refugees supported by special schemes (if it has not been possible to include the amounts provided by such schemes under imports).

The per caput supply figures in the food balance sheets represent only the average supply available for the population as a whole and do not necessarily indicate what is actually consumed by individuals. Even if the per caput food supply is taken as an approximation of per caput consumption, it is important to bear in mind that there could be considerable variation in both levels and patterns of consumption between individuals.

For the purpose of calculating the caloric value and the protein and fat content of the per caput food supplies, the choice of the appropriate food composition factors is very important. For example, the choice of the food composition factors for wheat flour depends, among other factors, on the water content, variety, and the degree of milling involved. The choice of the corresponding factors for cheese depends on whether the cheese is derived from whole milk, partly skimmed milk or skim milk, as well as whether the cheese has been made from the milk of cows, sheep, goats, buffaloes or camels, and lastly on whether the cheese is hard, semi-soft or soft. The nutritive factors can be obtained directly from national food composition tables. These tables give the nutritional composition of food per 100 grams of edible portion. As the quantity data of the food balance sheets are on an "as purchased" basis, i.e. as the food leaves the retail shop or otherwise enters the household, it is necessary that the nutritive composition in term of edible portion is converted into this basis as well. The conversion is made by applying waste/refuse factors to the nutritive composition in term of edible portion. The resulting per caput total nutritive values are usually expressed on a daily basis. In the absence of food composition tables prepared by appropriate national institutions, use can be made of FAO's food composition factors as shown in the appendix.

For calories, protein and fat, a grand total and its breakdown into components of vegetable and animal origin is shown at the beginning or the end of the food balance sheet.

3. FORMATS OF FOOD BALANCE SHEETS

Various formats which have been developed over the years still exist and can be used for the preparation and presentation of food balance sheets. The three "Sample Forms for Food Balance Sheets" that are shown, have different headings for various columns that need some further explanations.

FORMAT I

Available supply represents the concept of supply available for domestic utilization.

Food (gross) is simply the balance of the available supply after feed, seed, food manufacture and waste have been deducted. It represents the quantities directly available to consumers before the application of extraction rates, if this is necessary.

Extraction rate applies chiefly to cereals and is used to effect a conversion of grains to flour and of paddy rice to milled rice. This column is also used to show the extraction of raw sugar from cane and sugar beets and of oil from oilseeds and so on. In addition to reflecting the input/output ratio between originating/parent commodity and processed commodity, the extraction rate also determines the choice of the appropriate food composition factors.

Food (net) represents the actual quantities of food directly available for human consumption after the application of extraction rates to the corresponding figures in the Food (gross) column.

Columns 18-20 show the food composition factors which have been applied when converting the quantities of daily per caput food supplies into energy, protein and fat content.

FORMAT II

The headings in this second format correspond to the description of the various elements in the foregoing section on "Supply and Utilization Elements".

Input and Output. For production, a distinction is made between "Input" and "Output". For derived commodities, amounts of the originating commodity required for obtaining the output of the derived product are indicated under "Input", expressed in terms of the originating commodity. The various factors used, i.e. milling rates, extraction rates, conversion or processing factors, carcass weights, milk yield, egg weights, etc., should indicate the average national rate at which these commodities are generally converted.

FORMAT III

This third format may be used when presenting a food balance sheet in standardized form.

Processed Trade (E-I) shows exports minus imports of processed commodities expressed in their primary/parent commodity equivalent and where "E" denotes exports and "I" denotes imports.

Stock changes indicate increases (+), or decreases (-), in stocks.

Food Manufacture shows amounts of the commodity in question used to manufacture processed commodities which are part of a separate food group (e.g. fats and oils, beverages).

Other uses comprises quantities used for the manufacture of non-food products, e.g. oil for soap. In order not to distort the picture of the national food pattern, quantities mainly consumed by tourists may be included here.

Food. In many cases, commodities are not consumed in the primary form in which they are presented in the standardized food balance sheets, e.g. cereals enter the household mainly in processed form, such as flour, meal, husked or milled rice. To take this fact into account, the caloric value and the protein and fat content shown against primary commodities in the standardized food balance sheet should be derived by applying the appropriate food composition factors to the quantities of the processed commodities and not by multiplying the quantities shown in the food balance sheet with the food composition factors relating to primary commodities.

FORMAT IV

This format is used when describing the procedures for the preparation of food balance sheets in the following section.

Whatever form is used, the unit of measurement (e.g. thousand metric tons or metric tons) should be stated. Equally important is also to indicate the cut-off date to which the figures shown in the food balance sheet refer.