Metallic food control

Food quality control is critical to consumer safety and satisfaction. Knowing levels of inorganic analytes, such as the toxic elements arsenic, cadmium, chromium, and lead, is important, as is information on macro-nutrients like calcium, potassium, magnesium, sodium, phosphorus, and sulfur and micronutrients (copper, iron, manganese, and zinc). Fabiola Manhas Verbi Pereira, Edenir Rodrigues Pereira-Filho, and Maria Izabel Maretti Silveira Bueno of the Universidade Estadual de Campinas (UNICAMP) and Centro de Ciencias Exatas, Ambientais e de Tecnologias (CEATEC), Pontificia Universidade Catolica de Campinas (PUC-Campinas), in Sao Paulo, and the Federal University of S?o Carlos (UFSCAR), Brazil, point out that sample pre-treatment is often the rate-determining step in analysing food stuffs for metal ions. They suggest that an alternative approach would combine fast sample preparation, or better still no sample pre-treatment, with a good detection method. This, they explain, will not only speed up the analytical process but also keep costs down. They tested their new approach on fifteen purchased tea samples from a local market, recording the XRS spectra with no sample pre-treatment. For comparison purposes, they also mineralized the samples and determined six metallic elements using flame atomic absorption spectrometry (for calcium, iron, magnesium, and manganese), flame atomic emission spectrometry (for potassium), and thermospray flame furnace atomic absorption spectrometry (for zinc). The team then used the data from each distinct experiment - XRS spectra and could measure Ca, K, and Mg concentrations using the PLS models. For Fe, Mn, and Zn, concentrations were obtained using semiquantitative metal analyses. The cost of this methodology is about a tenth that of conventional methodology, which usually requires sample mineralization and atomic spectrometry. The researchers explain that they can improve the PLS models by using additional tea samples. Moreover, because they do not need to mineralize samples for the XRS experiments, the approach could easily be adapted for other products in the food and agricultural industries. "The proposed methodology can be easily applied for food or agricultural product quality control," the team says. The food industries are very interested in metal concentrations as these often have to be included on food labels as well as levels being restricted by law, Bueno explains. "A priori, the method can be used for any type of food. We are using it for sugars, coffee, seeds, juices and so on," she revealed to SpectroscopyNOW.com. "Source": [http://www.spectroscopynow.com/coi/cda/detail.cda?id=14307&type=Feature&chId=9&page=1]

---