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Study Notes: Sample Description and Reporting

Part of a laboratory technician’s analytical duties may be to perform a visual inspection of a sample as one of the tests requested by the customer. Other types of sensory analysis, including assessment of odour and taste, may also be requested depending on the nature of the sample. Sensory analysis is critical in industries such as food and flavours, but of course would never be used when working with toxic, radioactive or pathogen containing samples.

The technician would know from previous history or from a documented specification how the sample should look, smell and taste (and possibly feel also). A specification might, for instance, state that the sample must be ‘free flowing’, ‘blue in colour’, ‘free from foreign matter’ or ‘no obvious indications of bacterial infection or fungal contamination’. Any discrepancy with the specification would, of course, require an appropriate response from the technician, including recording and reporting the observations in line with enterprise procedures. A Technical Specification Manual

Whether or not sensory examination is requested, the laboratory technician should always be in the habit of asking the question before attempting any work:

“Is this sample what it is supposed to be?”

If you understand that the sample is meant to be white bread and it looks like multi-grain bread, it could well be a wasted exercise to proceed with the test work (or worse still, report misleading results to the customer).

Possible explanations of a sample not appearing as expected may be that:

  • the wrong sample was taken
  • the wrong label was affixed
  • there was a mix-up along the sample handling chain
  • the bulk material from which the sample was taken was not what the customer thought it was – for example, instead of a tank containing orange lemonade (as planned) it was filled with cola by mistake
  • the sample is fine but the specifications of the product have changed. For instance , in an attempt to attract a new customer base, the recipe has been changed.

If the sample is what it is supposed to be, the next question the technician should be asking is:

“Is the sample in its intended condition for analysis?”

The issue behind this question is whether the nature of the sample has changed between the time the sample was taken and when analysis occurs. Change may have come about as the result of natural deterioration, always a potential problem with food. External contamination may also be a factor. The quality of the sample packaging can play a role here if, for instance, it is dirty or does not have an effective seal thus allowing entry to infecting organisms or the escape of essential ingredients.

It may also be that there is nothing wrong with the sample – the issue is that the bulk material was contaminated or had deteriorated at the time of sampling.

Good communication on the part of all parties is required to ensure that mistakes do not arise from confusion.

Depending upon how the chemical, microbiological and physical properties have been affected, the results of analysis may not be reliable. Again, time would be wasted doing the test work and the results, if reported to the customer, may be misleading (and may inadvertently be used to make important decisions). A SimuLab Laboratory Test Sheet showing test results and ready for dispatch to the customer.

A sample that is not what it is meant to be or that shows signs of deterioration or contamination should trigger the technician to record and report the discrepancy. Decisions then need to be made to contact the customer, take a fresh sample, proceed with the analysis or cease the work altogether.

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