Food sampling
Encyclopedia
Food sampling is a process used to check that a food is safe and that it does not contain harmful contaminants
, or that it contains only permitted additives
at acceptable levels, or that it contains the right levels of key ingredients and its label declarations are correct, or to know the levels of nutrient
s present.
A food sample is carried out by subjecting the product to chemical analysis. Analysis may be undertaken by or on behalf of a manufacturer regarding their own product, or for official food law enforcement or control purposes, or for research or public information.
To undertake any analysis, unless the whole amount of food to be considered is very small so that the food can be used for testing in its entirety, it is usually necessary for a portion of it to be taken (e.g. a small quantity from a full production batch, or a portion of what is on sale in a shop) – this process is known as food sampling.
In most cases with food to be analysed there are two levels of sampling – the first being selection of a portion from the whole, which is then submitted to a laboratory for testing, and the second being the laboratory’s taking of the individual amounts necessary for individual tests that may be applied. It is the former that is ‘food sampling’: the latter is analytical laboratory ‘sub-sampling’, often relying upon initial homogenisation of the entire submitted sample.
Where it is intended that the results of any analysis to relate to the food as a whole it is crucially important that the sample is representative of that whole – and the results of any analysis can only be meaningful if the sampling is undertaken effectively. This is true whether the ‘whole’ is a manufacturer’s entire production batch, or where it is a single item but too large to all be used for the test.
Factors relevant in considering the representativeness of a sample include the homogeneity of the food, the relative sizes of the sample to be taken and the whole, the potential degree of variation of the parameter(s) in question through the whole, and the significance and intended use of the analytical result.
In the United Kingdom although various guidance is available, either from manufacturers’ associations or from sources of standards such as British Standards Institution
(such as British Standard BS6001), some of which may be relevant to certain food types. It is largely down to manufacturers to make their own evaluations of need and suitability. This must be translated into an assessment both of sample portion size and number, and the frequency of taking samples.
, enforcement is under the Food Safety Act 1990. Food sampling is undertaken primarily by local authorities
and port health authorities for submission to public analyst
s for analysis. Much of the legislation relates to food as supplied to a consumer, meaning that every portion of a size as may be supplied to a consumer has to comply, so that in such cases the sample submitted for analysis could simply be an entire consumer-sized portion. There are exceptions, however, such as the sampling of nut products for the presence of aflatoxin
s, which stipulate a primary sample size related to the size of the consignment – with associated requirements for initial homogenisation to produce a smaller sample to be sent for analysis.
The Food Safety Act 1990
affords a right for defence analysis, and for referee analysis in case of disputed analytical results, by stipulating that except where to do so would prevent effective analysis the sample must be divided into three parts. The UK Food Standards Agency
provides supplementary guidance to the enforcement authorities to assist with the sampling process and associated decisions by sampling officers.
There is no set frequency or rate for the sampling of food for law enforcement in the UK. Between the 1930s and 1990s there had been a guideline minimum rate for sampling for chemical analysis (not including samples for microbiological examination) of 2.5 samples per annum per 1000 head of population, however that was an arbitrary figure and more recent thinking suggested that the selection of a frequency for sampling should be based on risk. In this context risk includes all 'consumer protection' issues such as pecuniary disadvantage from substandard or counterfeit products, as well as risk to health. The Association of Public Analysts was commissioned by the Food Standards Agency to look into this, culminating in a scheme for Risk Based Sampling , though it has not yet been adopted by the enforcement authorities.
Food contaminants
Food contamination refers to the presence in food of harmful chemicals and microorganisms which can cause consumer illness. This article addresses the chemical contamination of foods, as opposed to microbiological contamination, which can be found under Foodborne...
, or that it contains only permitted additives
Food additive
Food additives are substances added to food to preserve flavor or enhance its taste and appearance.Some additives have been used for centuries; for example, preserving food by pickling , salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines...
at acceptable levels, or that it contains the right levels of key ingredients and its label declarations are correct, or to know the levels of nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...
s present.
A food sample is carried out by subjecting the product to chemical analysis. Analysis may be undertaken by or on behalf of a manufacturer regarding their own product, or for official food law enforcement or control purposes, or for research or public information.
To undertake any analysis, unless the whole amount of food to be considered is very small so that the food can be used for testing in its entirety, it is usually necessary for a portion of it to be taken (e.g. a small quantity from a full production batch, or a portion of what is on sale in a shop) – this process is known as food sampling.
In most cases with food to be analysed there are two levels of sampling – the first being selection of a portion from the whole, which is then submitted to a laboratory for testing, and the second being the laboratory’s taking of the individual amounts necessary for individual tests that may be applied. It is the former that is ‘food sampling’: the latter is analytical laboratory ‘sub-sampling’, often relying upon initial homogenisation of the entire submitted sample.
Where it is intended that the results of any analysis to relate to the food as a whole it is crucially important that the sample is representative of that whole – and the results of any analysis can only be meaningful if the sampling is undertaken effectively. This is true whether the ‘whole’ is a manufacturer’s entire production batch, or where it is a single item but too large to all be used for the test.
Factors relevant in considering the representativeness of a sample include the homogeneity of the food, the relative sizes of the sample to be taken and the whole, the potential degree of variation of the parameter(s) in question through the whole, and the significance and intended use of the analytical result.
Sampling by manufacturers
Food manufacturers and producers would need to satisfy themselves that any sample taken for analysis is sufficiently representative of the food for the analytical result to be meaningful. This is true whether the data are to be used as the basis of labelling declarations, assurance of compliance with legislative or other standards, monitoring of production as part of HACCP (Hazard Analysis and Critical Control Points), or for routine quality control.In the United Kingdom although various guidance is available, either from manufacturers’ associations or from sources of standards such as British Standards Institution
British Standards
British Standards are the standards produced by BSI Group which is incorporated under a Royal Charter...
(such as British Standard BS6001), some of which may be relevant to certain food types. It is largely down to manufacturers to make their own evaluations of need and suitability. This must be translated into an assessment both of sample portion size and number, and the frequency of taking samples.
Food law enforcement (UK)
In the United KingdomUnited Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
, enforcement is under the Food Safety Act 1990. Food sampling is undertaken primarily by local authorities
Local government
Local government refers collectively to administrative authorities over areas that are smaller than a state.The term is used to contrast with offices at nation-state level, which are referred to as the central government, national government, or federal government...
and port health authorities for submission to public analyst
Public Analyst
Public Analysts are scientists in the United Kingdom and the Republic of Ireland whose principal task is to ensure the safety and correct description of food by testing for compliance with legislation. Most Public Analysts are also Agricultural Analysts who carry out similar work on animal...
s for analysis. Much of the legislation relates to food as supplied to a consumer, meaning that every portion of a size as may be supplied to a consumer has to comply, so that in such cases the sample submitted for analysis could simply be an entire consumer-sized portion. There are exceptions, however, such as the sampling of nut products for the presence of aflatoxin
Aflatoxin
Aflatoxins are naturally occurring mycotoxins that are produced by many species of Aspergillus, a fungus, the most notable ones being Aspergillus flavus and Aspergillus parasiticus. Aflatoxins are toxic and among the most carcinogenic substances known...
s, which stipulate a primary sample size related to the size of the consignment – with associated requirements for initial homogenisation to produce a smaller sample to be sent for analysis.
The Food Safety Act 1990
Food Safety Act 1990
The Food Safety Act 1990, is an Act of the Parliament of the United Kingdom. It is the statutory obligation to treat food intended for human consumption in a controlled and managed way....
affords a right for defence analysis, and for referee analysis in case of disputed analytical results, by stipulating that except where to do so would prevent effective analysis the sample must be divided into three parts. The UK Food Standards Agency
Food Standards Agency
The Food Standards Agency is a non-ministerial government department of the Government of the United Kingdom. It is responsible for protecting public health in relation to food throughout the United Kingdom and is led by a board appointed to act in the public interest...
provides supplementary guidance to the enforcement authorities to assist with the sampling process and associated decisions by sampling officers.
There is no set frequency or rate for the sampling of food for law enforcement in the UK. Between the 1930s and 1990s there had been a guideline minimum rate for sampling for chemical analysis (not including samples for microbiological examination) of 2.5 samples per annum per 1000 head of population, however that was an arbitrary figure and more recent thinking suggested that the selection of a frequency for sampling should be based on risk. In this context risk includes all 'consumer protection' issues such as pecuniary disadvantage from substandard or counterfeit products, as well as risk to health. The Association of Public Analysts was commissioned by the Food Standards Agency to look into this, culminating in a scheme for Risk Based Sampling , though it has not yet been adopted by the enforcement authorities.