Nordic co-operation in dairy hygiene: DairyNET

Development of detection and identification methods for assessing microbial and organic soil on surfaces, in air, on packaging and in raw material as well as products are needed to ensure that the results obtained are reliable and repeatable. In an industrial point of view it is important to maintain and extend the interactive contacts between persons dealing with safety and environmental questions in Nordic dairies. The aim of this Nordic dairy hygiene network project, DairyNET – Hygiene control in dairies, is to provide reliable methods for validating and improving cleaning and hygiene in process scale at dairies by applying new knowledge and by using available laboratory and pilot scale equipment in the experimental set-ups. Nordic Industrial Fund, national technology agencies as well as industrial and research partners are funding this network. The Finnish research started with mapping the air, CIP water and ice water quality in a yoghurt manufacturing dairy. The initial findings showed that the air quality within the controlled environments must be monitored regularly, some of the routines must also be changed to improve the air within the equipment. Cleaning trials in pilot scale is being carried out for optimisation of the parameters in the ultrasound cleaning planned for cleaning milk crates. In the Danish national project the work will mainly focus on sanitising effects and design of hygienic equipment and process flow as parts of hygiene management. The Icelandic project will study the sources and contamination routes for Listeria spp. in raw milk samples during different seasons. Samples are also collected from various dairy products and from the production environment. Possible isolates found in the survey will be characterised and tested against sanitizers. In Sweden a checklist for the hygiene in cheese production facilities defining every process step including the function, perquisites, objectives, methods for measurement and documentation and deviation steps has been processed. The quality of water and air, as well as the effect of aerosols in spreading microbes will be investigated. Studies on existing cleaning routines and innovative solutions in order to prevent contamination during cleaning/ production as well as the efficiency of washing equipment in reducing biofilms will also be studied. Milk from five dairies in Norway using two different disinfection systems will be sampled from one silo-tank through the line to pasteurisation. The occurrence of vegetative and spore-forming bacteria in the milk samples, swabbing samples and on gaskets will be determined. The isolates will be tested for disinfectant resistance and adhesion ability.