The importance of diluents in microbiological analysis of foods
Why should food be analyzed?
The significance of food analysis lies in its role as an optimal environment for the growth of microorganisms, posing potential health risks to consumers. The microbiological analysis of food products entails crucial steps—sampling, transportation, preparation, and analysis—to ensure reproducibility and reliability.
Following the receipt of a sample, the preparation process becomes paramount. Various methods and media are employed in the analysis of bacteria and fungi. A critical consideration is the non-uniform distribution of microorganisms in the sample; while some are surface-bound, others exist within the product.
Furthermore, diverse food types contain an array of ingredients, each harboring its unique bioburden. This variance impacts the sample’s moisture, water activity, and pH levels, consequently influencing the growth of microorganisms.
Moreover, it is essential to note that sample preparation may involve homogenization in certain instances, potentially damaging present microorganisms and compromising their detection.
These factors contribute to significant result discrepancies in ostensibly ‘identical’ samples.
To mitigate variability in analyses, the cornerstone of any analytical method—the diluents—plays a crucial role.
According to the ISO 6887-1 standard, differentiation can be made between general-purpose and specialized diluents. The former typically comprises three primary media: Buffered Peptone Water (at normal and double concentrations), Saline Peptone Water (commonly referred to as a universal diluent), and Ringer’s solution 1/4x.
Conversely, for tailored diluents, reference should be made to the applicable standard or section within ISO 6887, containing six distinct sections for various food matrices. Sample media include:
In other words, ISO 6887 covers virtually every possible analysis scenario, establishing itself as the main standard in sample preparation for food analysis.
At Asiagel, we provide all the means available for you to follow your methodology while complying with regulations. Do not hesitate to contact us for further information.