A key issue for the European food industry, in particular the dairy industry, involves the fouling of the processing equipment upon heating. It is estimated that due to fouling approximately one fourth of processing time is downtime of the equipment for cleaning. Apart from processing interruption, the cleaning process is very demanding on rinsing water, which increases the processing costs. Moreover, the required use of cleaning agents can potentially lead to environmental problems. Fouling may also affect dairy product safety as the formation of deposits hinders the desired heat transfer that serves several purposes. These may be for assuring proper pasteurisation, stable flow and pressure conditions. Most importantly, fouling enhances bacterial growth in the cooling part of the heating equipment that may result in microbial contamination after pasteurisation. This can have a great impact on product quality with severe effects for consumer health. Answering this need the MODSTEEL project focused on the minimisation of fouling and optimisation of cleaning by changing the surface properties of the heating surface. Thereby, researchers used steel with special coatings that is less prone to fouling, while at the same time food quality is safeguarded. Samples of different surface modified steels with original finish were investigated for their fouling and cleaning behaviour. More specifically, transfer tests showed that silica and excalibur coatings released small amounts of Si in soda. The Ni-P-PTFE coating resulted in Ni releases in acetic acid, which is almost completely dissolved in nitric acid. Additionally, possible releases of Ni in the dairy products through ingestion may lead to dermatitis incidents. On the other hand, a special Ni-free hydrophobic coating showed no release in the dairy product and a small release in soda. Under testing for formability Ni-P-PTFE, Xylan and the Ni-free hydrophobic coatings displayed a good adherence to the substrate. Further research/development support is sought for use of the modified plates in the heat exchangers without any adverse effects on consumer health.
Improvement of construction materials used in the food industry to lengthening processing time (MODSTEEL)
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5 March 2018