Microscopic Advancements Aid Food QC Labs
Jeffrey D. McGinn
Laboratory Equipment - September 4, 2014
Recent advances in scanning electron microscopy (SEM) and thermal stage microscopy have served to enhance quality control procedures of laboratories within the food industry. Modifications to instruments allow for rapid, onsite sample analysis, reducing turnaround time for work that may have been previously outsourced. The current state of SEM and thermal stage technology allows for companies to perform their own analyses in their own laboratories in as little as 15 minutes. These time-saving measures, for example, enable the quality control scientist to quickly measure the coating of a candy bar to determine the temperature at which starch grains will gelatinize, or to investigate failures in food packaging materials.
A scanning electron microscope reveals information about changes in microscopic properties and particles that may affect the structural properties of food products. This information may include chemical composition, morphology and contaminant identification. SEM is often used in conjunction with energy dispersive X-ray spectrometry (EDS) for mapping and contamination analysis, but the majority of work performed by SEM for quality control includes the examination of coatings, or identification of contaminants. The types of signals produced by SEM include secondary electrons (SE) and back-scattered electrons (BSE). SE imaging can produce high-resolution images of the sample surface, often less than 1 nm in size. BSE imaging is particularly useful in providing information about the distribution of different elements within the sample, since the intensity of the BSE signal is closely related to the atomic number of the sample.