Food Microbiology & Nutrition

Statement of the Problem: Broadband acoustic resonance dissolution spectroscopy (BARDS) is a new tool for characterizing powders, blends and tablet formulations. Food powders, from salts to dairy products, represent a significant percentage of food ingredients and products. It is also a convenient stage at which to adulterate a product in the production chain. There have been many high profile examples in recent times, most notably with deliberate adulteration and contamination of infant food formulations in China. In this study BARDS will be shown to be an effective method of monitoring the quality/provenance of food grade powders and slats by establishing baseline data as a control against which comparator measurement can be made by a simple and rapid dissolution test.

Methodology & Theoretical Orientation: Figure 1 shows a BARDS instrument used for powder/sample testing. The sample is added from a weighing boat on an automated tipper. A magnetic stirrer is used to create resonant frequencies in the dissolution vessel by gently tapping the inner wall. The sample is added after 30 seconds which causes changes in the resonant frequencies which are intrinsic to the sample. The changes are caused by gas trapped between particles and within particles and also due to its reduction in gas solubility in the solution due to dissolution. This causes changes in the solubility of the solvent which reduces the speed of sound of the resonant frequencies. The frequency returns to steady state as the gas exits the solution.

Findings: Food powders produce acoustic signatures related to the constituents, physical properties and provenance of the powder.

Conclusion & Significance: BARDS acoustic profiles can be used as an indicator of the provenance of a powder sample upstream in quality control before more sophisticated techniques are required.