South African Food Data System

1857 food items

Sampling

The importance of appropriate sampling
Food sampling concerns the selection of the individual units of food, food products or bulk foodstuffs from the food supply or source, whether it be from the land, market place, manufacturing/food outlet or from the homes of the members of the study population (field sample). One of the main objectives of food sampling is to provide representative mean values for individual components (nutrients) in foods.

Food sampling is a critical step in the generation of food composition data of high quality. Analytical costs are high and should the wrong sampling protocol be followed the analysis could be a waste of time and money.

A schematic overview of the stages involved in the sampling plan for food analysis is shown below to serve as a guideline for compiling a sampling protocol for a specific study. (Click on the steps shown below for more information)

Identify food to be analysed
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Identify regions/areas/sites for sampling
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Determine and collect the most used foods/recipes/cooking methods per region/sampling area
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Isolate the places and times to select samples
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Identify nutrients to be analysed
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Identify analytical laboratory and methods for analysis
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Identify the representative field sample amount (g) required to be collected
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Determine the sample size
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Identify analytical sample amount (g) required for analyses
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Draw up the final sampling protocol
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Collect samples from the selected markets/areas
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Mark samples clearly and record collection procedure properly
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Transport samples to laboratory according to required guidelines within minimum time frame
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Process the samples for analyses or storage
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Chemical analyses according to appropriate methodology
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Reporting of data
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The main reference source for the information summarised in this webpage is: Greenfield H & Southgate DAT. Sampling. Food Composition Data. Chapter 5. 2003, pp 63-82. Read more.

For further reading the following reading material can also be consulted.

Sampling comments/questions can be forwarded to safoods@mrc.ac.za