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Using quartz crystal microbalances (QCM) to monitor cleaning processes creates new opportunities towards efficient and need-based cleaning processes. A first study with starch as food model soiling showed the suitability of a QCM-based sensor concept to detect swellable substances and monitor the cleaning process [1]. The results of a follow-up study will be presented in this manuscript. Cleaning tests were conducted at 40 and 55 °C while monitoring a range of characteristics (peak height, attenuation, integral, tangent incline, turning point) in the sensor signal course. An optical sensor, monitoring the cleaning process was used as a reference. Based on this, the most promising parameters (peak height, attenuation, tangent incline) were selected to develop an evaluation algorithm counteracting the sensor cross-sensitivity towards process parameters such as temperature and influences of the cleaning fluid. The algorithm can determine whether the sensor surface is clean or soiled. Cleaning tests with tomato paste and milk proved the sensor's ability to detect industrial food products with an average deviation of 68,0 s (tomato paste) and 43,8 s (milk) from the reference sensor. [ABSTRACT FROM AUTHOR]

Reproducible cleaning of open geometries and vessels in the food industry is usually ensured by Cleaning-in-Place systems, which spray the cleaning fluid onto the surfaces to be cleaned. The discontinuous operation of nozzles is one possibility to improve the efficiency of these operations. Therefore, the influence of various parameters on the cleaning process is investigated in an experimental study for the simplified configuration of a vertical water spray impinging downwards on a horizontal stainless steel surface at a distance of 150 mm. The industrial full cone and flat fan nozzles used in this research delivered volumetric flow rates of 5.5 and 8.01/min, respectively, at an operating pressure of 6 bar. Discontinuous flows were generated by switching a pivoted-armature valve upstream of the nozzle with frequencies of 5 and 10 Hz. Vanilla pudding and rice pudding were chosen as model food soils to study the cleaning properties of a homogeneous soil layer and a soil layer with protruding particles, respectively. The use of discontinuous sprays increased the cleaning rate because of altered fluid distribution in the spray and, in case of the inhomogeneous soil layer, due to repetitive load maxima. [ABSTRACT FROM AUTHOR]

Machine contamination poses serious problems to the food processing industry particularly from an economic and hygienic perspective. Various studies therefore investigated the impact of energy-related and topography-related surface properties on the contamination tendency and the cleanability of material probes. These tests were carried out with stainless steel as reference as well as 46 surface modifications taken from the area of polymer coatings, nanocomposite coatings and physical/chemical vapour depositions (PVD/CVD) on the basis of whey protein and starch contamination. The findings showed that starch deposits on modified surface specimens were reduced by up to 76% (Fluorinated ethylene propylene, FEP) in contrast to stainless steel. Whey protein deposits were reduced by up to 34% (nanocomposite). The remaining starch contamination after one spray cleaning was reduced by up to 50% (FEP) and the whey protein contamination was reduced by up to 88% (FEP). Comparing the roughness and surface energy with the contamination and cleaning behaviour yields no clear correlation. But depending on the kind of contamination there is the tendency that low energetic surfaces show a better cleanability or less deposits. Furthermore, the surface modifications tested showed different abrasion resistance and different levels of resistance to repeated stress with detergents. [Copyright &y& Elsevier]