For accurate analysis reports it is important thatthe food testing laboratories have obtainedhigh quality testing samples. A sample is stated to be of high quality when it is of adequate quantity and is representative of the entire food batch as a whole. This kind of sample testing material ensures better analysis and identification of hazards, their toxicological and nutritional characteristics. It is also helpful in estimating quantitative and reliable exposure levels of foods and related compounds which could be of concern to human health.
Sample preparation for testing
Along with proper collection of samples, sample preparation by the food testing laboratory and analysis with suitable methods and instrumentations are all important steps for correct analysis. Food testing laboratories understand the variations in sampling of foods including same foods. They have the technical know-how to avoid and minimise the potential sources of variation that can creep into food testing. To minimise variation food testing labs ensure there is proper sampling, correct sample pre-treatment and no damage to the samples before analysis. They ensure that the samples are
- of appropriate size
- stored the in suitable containers
- prevented from spoiling by using appropriate preservatives
Representative sampling for food testing
Representative sampling provides a good framework within which risk and analysis can be estimated in different areas of food production.A representative sample is extremely essential especially when the when pathogens or toxins are thinly distributed within the food or food product. The number of units that a representative sample must have from the designated lot must also be statistically significant. Therefore, the representative sampling statistics depends on the texture of the foods as they can be solid, semi-solid, viscous or liquid foods. The food testing laboratory must be adept at collecting the right quantity of food samples.
Food testing laboratories take several precautions during sampling such as the use of
- clean, dry, leak-proof and sterilecontainers of a suitable size
- all samples are brought to the laboratory in a sealed condition and are originals from the designated foods
- non-perishables like dry or canned foodsare collected at ambient temperatures and refrigerated
- for frozen samples the sample collecting containers are pre-chilled
- all storage norms are appropriately followed
Methodology and sampling go hand-in-hand
High quality sampling along with adoption of the correct testing methodology is crucial for monitoring food safety. There are modern methods that can be used in preparing samples for food analysis. Food sampling of biological origin whether liquid or solid has five rough divisions. Food testing laboratories make use of these divisions to understand how the samples must be isolated, what extraction solvent to use and the sample clean-up method. They also use testing methods that generate minimum chemical waste. Food testing laboratories know that food analysis can often be complex and so there are several techniques and methods that can rapidly test samples. However, the FSSAI sampling and testing methodologies are the basis which food testing laboratories use as they are tried and tested for accuracy and precision.