Greener bags of salad

By driving the innovative design of cleaning equipment, and by testing new decontamination techniques, partners in the European SUSCLEAN project have managed to control the microbiological risk while at the same time reducing the amounts of water and chlorine used in the production of ready-to-eat vegetables. The market for fresh, prepared and ready-to-eat vegetables has grown consistently during the past ten years.? In order to control the microbiological risks of these ready-to-eat foods, the industry generally uses sodium hypochlorite and large amounts of water. The use of chlorine, whose residues can form carcinogenic products (trihalomethanes) in waste water, is not without posing public health issues and there is currently no harmonisation of the regulations at a European level.? For countries that ban sodium hypochlorite, such as the Netherlands, Belgium and the UK, particularly large quantities of washing water are therefore consumed, which can reach more than 30 litres per kg of product (versus an average of 20 litres otherwise).? The Netherlands is now questioning this ban on chlorine, its objective being to reduce the risk of the presence of pathogens (E coli, Listeria, etc.) as cases of contamination have recently been reported.? France has fixed a threshold for contamination of 106 CFU/gram of finished product, which cannot be achieved without the use of chemical disinfectants.? Reconciling the imperatives of health safety and the environmental concerns linked in particular to the availability of water resources, were two of the aims of the European SUSCLEAN project? (Sustainable Cleaning and Disinfection in Fresh-Cut Food Industries). Optimised equipment designThanks to the acquisition of large quantities of data harvested from real ready-to-eat salad production lines, the scientists were able to understand the microbial contamination risks and demonstrate the importance of the hygiene design of equipment.? They were able to put figures on the consequences of different technical choices in terms of contamination rates and how rapidly this contamination can develop. A partner company in the project was able to put these lessons into practice by building an industrial prototype with an innovative design.? In the longer term,? a decision-making tool should help equipment manufacturers to take account of these hygiene design features, depending on the sector concerned. Alternative decontamination techniques to reduce water and biocide consumptionDifferent methods were tested: ultraviolet light, turbulence, cold plasma, acid electrolysed water, pulsed electrical fields, pulsed light, etc.? Of these, ozone proved to be one of the most promising methods to regenerate the salad cleaning water and put it back into circulation, as well as enabling potential water savings of around 20-42%.? An economic viability study is under way to validate industrialisation of this process.? Furthermore, neutral electrolysed water was also revealed as a good alternative because the amount of free chlorine necessary can be adjusted real-time during the process.? This is also the subject at present of a more detailed evaluation.Finally, it was shown that the level of chlorine necessary to maintain the safety of ready-to-eat foods is around the concentration that may be found in drinking water, notably in Spain. Guidelines and best practices accessible to allThree reference documents were produced: ? Code of the Best Practices for Cleaning and Disinfection ?, ? Guideline for Cleaning Suited Equipment ? and a ? Recommendation to the IPPC ?. These guides contain a series of protocols and procedures so that the techniques developed and optimised in the context of SUSCLEAN can be integrated in production lines. ? More information and sourcesThierry B?n?zech UMET Unit? Mat?riaux Et Transformations-59651 VILLENEUVE D'ASCQ CEDEXAssociated Division(s):? Science and Process Engineering of Agricultural ProductsAssociated Centre(s):???North-Picardy-Champagne ?? INRA Science and Impact