Final Report Summary - SMARTMILK (A novel system for the treatment of milk based on the combination of ultrasounds and pulsed electric field technologies)
Executive summary:
SMARTMILK was a two-year applied research project, which commenced in October 2010 and finished in December 2012, and was funded under the 'Research for Small and medium-sized enterprise (SME)s' programme of the European Commission (EC)'s Seventh Framework Programme (FP7).
The European Union (EU) dairy industry produces 130 billion litres of raw milk each year for consumption and for application in the production of many food, feed and pharma products. Without doubt the quality and safety of milk and milk products is of paramount importance for safeguarding the health and safety of EU consumers. Pasteurisation of milk is very simple and effective in eliminating disease-causing germs, as it kills bacteria, yeast and fungi by heating the product. However, due to its high temperatures, pasteurisation damages heat labile compounds, significantly changing the taste of the final product and reducing the levels of vitamins and bioactive compounds. Clear market value would be derived by providing milk producers with an alternative milk treatment technology to pasteurisation that retains some of the beneficial components and natural flavours of milk, while ensuring quality and safety for consumers.
To this end, the SMARTMILK projects aimed at developing a technology that required milder treatment conditions, to substantially reduce the severity of the time / temperature exposure, while achieving similar shelf life to the conventional treatment. SMARTMILK combines pulsed electric field (PEF), with moderate heat and pressure - manothermosonication (MTS), to achieve a degree of inactivation of microorganisms comparable with conventional pasteurisation. The combination of PEF and MTS exploits the ability of the two technologies to act in a synergistic manner against the microbial population. This treatment employs milder conditions compared to pasteurisation resulting in a lesser degree of thermal damage to the milk.
The developers of SMARTMILK were committed to making this system affordable, robust and easy to maintain. Achieving this makes the technology accessible to European dairy processors, whereby they will benefit from being able to differentiate their products. SMARTMILK enables milk processors to meet with growing trends amongst consumers for milk that is safe but which retains more of the natural and taste characteristics of raw milk, while offering comparable shelf-life, along with enhanced nutritional and quality attributes compared to pasteurisation. The impact of the results also holds benefits for consumer safety and confidence, which will in turn impact on the competitiveness of thousands of European milk processing SMEs.
Project context and objectives:
Pasteurisation of milk is very simple and effective in eliminating disease-causing germs, as it kills bacteria, yeast and fungi by heating the product. However, due to its high temperatures, pasteurisation damages heat labile compounds, significantly changing the taste of the final product and reducing the levels of vitamins and bioactive compounds.
Due to its higher proportion of beneficial microorganisms and vitamins, and natural taste, an increasing number of consumers have expressed interest in drinking unpasteurised or raw milk. Clear market value would be derived by providing milk producers with an alternative milk treatment technology to pasteurisation that retains some of the beneficial components and natural flavours of milk, while ensuring quality and safety for consumers.
The SMARTMILK project aimed at developing milder treatment conditions, to substantially reduce the severity of the time / temperature exposure, while achieving similar shelf life to the conventional treatment. The overall objective of this project was to develop and build a precompetitive milk treatment system based on the novel combination of MTS and PEF technologies, as well as to test and validate the performance of the system for the effective treatment of milk and to compare the results with conventional pasteurisation treatment.
The specific objectives can be summarised as follows:
1. to use the results of a 'bottom-up' research approach to gain a understanding of the industrial needs and define the specifications of the SMARTMILK system;
2. to ensure the microbial effectiveness of the proposed combined MTS / PEF technology by carrying out laboratory trials;
3. to optimise the operating parameters of the combination of MTS and PEF to maximise the microbial inactivation while minimising the degree of thermal damage in the milk;
4. to define the parameters for the upscale of the laboratory results;
5. to draw up industrial designs for the SMARTMILK precompetitive prototype in keeping with specifications defined in WP1 and the parameters defined in WP2;
6. to build a precompetitive SMARTMILK prototype following the designs from objective 3 above;
7. to install, test and validate the SMARTMILK system in a real industrial environment;
8. to carry out quality tests on milk that has been treated with the SMARTMILK system and to compare them with milk treated using conventional treatments;
9. to evaluate and validate SMARTMILK treated milk for the processing of cheese and yoghurt;
10. to carefully outline scaling-up rules and development work for full production;
11. to facilitate the uptake of the SMARTMILK results by the participating SMEs, as well as by a wider audience, by carrying out demonstration activities.
The overriding goal of this project was to ensure that the pre-competitive SMARTMILK prototype resulting from this project fulfils the threshold requirements to ensure its further development post-project into a fully industrial system that is taken to market.
Project results:
The project started by understanding the technological and market needs of the European dairy industry in WP1. To do this, a questionnaire-based on-line survey directed to milk processors, cheese-makers, yoghurt manufacturers and dairy equipment providers was implemented. The survey was sent to approximately 750 dairy industries across Europe. In addition, in-depth consultations were conducted with a selected group of industry stakeholders. In total ten on-site visits were made to sites in Spain and Ireland. Furthermore, a literature, legislation and patent review was carried out. Outputs from this WP were used to define the desired industrial specifications of the SMARTMILK system.
In parallel to the previous work package, experimental procedures aimed at establishing the ability of the two individual technologies (MTS and PEF) to inactivate microorganisms of concern (or surrogates of them) for the milk industry were performed in WP2. E. coli and Pseudomonas were inactivated to a comparable level to conventional pasteurisation, though the gram+ organism (S. aureus) was inactivated to a slightly lesser extent than in heat processing (a phenomenon about gram+ organisms (most likely due to the thicker peptidoglycan layer in their cell membrane) which has also been noted by other workers). Other additional work which was included was the potential for paired combinations of PEF and US to inactivate Mycobacterium smegmatis (a non-pathogenic surrogate for M. tuberculosis).
Following this work, several operating parameters conditions for a combined MTS/PEF approach were tested and optimised to ensure effective microbial inactivation while minimising the thermal damage to the product. No differences were found in pH, conductivity or macro composition. In terms of colour the US / PEF treated milk was lighter and yellower than conventional pasteurised milk. The US / PEF treatments also had smaller emulsion particle sizes compared to conventional pasteurised milk (which was most likely due to the homogenisation of the milk by ultrasound). Vitamins B2 and B3 were not affected by the PEF / US treatments though B1 was reduced at more severe treatments. Native flora were inactivated to a comparable extent in milk which has been homogenised though in non-homogenised milk, comparable inactivation to pasteurisation was only observed under the most severe (i.e. HH) energy conditions. In terms of sensory evaluation, panellists could find no difference between raw, pasteurised or US/PEF processed milk in terms of colour intensity, liking the colour, consistency and transparency. They noted that the conventionally pasteurised and raw milk displayed higher clinginess to the cup (most likely due to the fact that they were less homogenised). However, panellists preferred the aroma of the raw and conventionally pasteurised and found the aroma intensity of the US / PEF treated to be higher.
TVC, Psychrotrophs, Pseumonads, Lactobacilli, Enterococci, Staphlococcus aureus and yeasts and moulds were examined from a microbial perspective while the enzymes alkaline phosphatase and lactoperoxidase were also assessed. From a microbial perspective, all treatments reduced the microbial load compared to untreated milk. US / PEF at higher temperatures was generally comparable to conventional pasteurisation. Similarly with enzymes, US / PEF generally produced comparable inactivation to conventional pasteurisation. The evolution of physical and chemical properties over shelf life was also compared to conventionally heat treated. Overall, in terms of shelf life, US / PEF treated were comparable to heat treated products.
WP2 concluded by defining a range of processing parameters (e.g. PEF field strength, cell geometry, pulse width and US power output, temperature regulation and processing chamber) necessary to perform a scale up of the equipment.
The SMARTMILK technology was scaled up during the second period of the project in order to build a pre-competitive prototype that could treat fresh milk-as an alternative to the traditional pasteurisation- by a synergistic combination of ultrasonication and PEF treatments. The prototype SMARTMILK unit served to prove the concept in industrial conditions; however it is not suitable for systematic industrial exploitation. It was designed in a modular fashion to allow for flexibility for tests / improvements and, simultaneously, to provide safe operation in moderate harsh environments. The system is based on a circuit for continuous circulation of the milk through the ultrasonication and the PEF chambers. It comprises not only these chambers, but also an ultrasound power generator, a pulse forming network, a high voltage power supply, a refrigeration unit, a peristaltic pump and a control unit. These elements are contained in a robust housing, which can be easily transported and used in typical industrial dairy plants.
The functionality of the prototype system was tested and the technology validated in the pilot plant facilities of CSIC in Spain, for the treatment of milk, as well as for suitability for cheese-making and yoghurt manufacture.
Milk shelf-life assays (5 degrees Celsius, 12 days) with SMARTMILK treated milk were compared with HTST pasteurisation (72 degrees Celsius, 15 s). SMARTMILK was slightly less effective than HTST to decrease the total viable counts (TVC), although a similar trend throughout the storage period was observed. Of note, SMARTMILK was able to inhibit the outgrowth of Bacillus cereus spores while HTST was not. SMARTMILK initially increased the pH of milk and it was kept slightly below HTST milk during storage. A 6 % decrease in total solids was detected in SMARTMILK milk mostly due to a decrease of the protein fraction. SMARTMILK did not alter the overall gross composition of milk. The main difference in the volatile profile was noticed at the end of the storage mainly due to the presence of ethanol in HTST milk that was absent in SMARTMILK. Interestingly, the availability of ionic calcium was higher in MTE-PEF milk than in HTST. This result suggests that it would not be necessary to supplement SMARTMILK milk with CaCl2 for cheese making as it is usual for cheese manufacture with HTST milk. The coagulation ability of SMARTMILK was similar or even higher than that of raw milk but it varies greatly depending on the flow rate during the SMARTMILK treatment. At the conditions tested, SMARTMILK clearly affected milk colour. In fact, the CIELAB colour difference ?E* between SMARTMILK and raw milk was 2.2303 compared with 0.3103 between HTST and raw milk. SMARTMILK treatment also exerted a sort of homogenisation as no cream layer developed during storage. A detailed report on tasks 5.1 and 5.2 can be found in D5.1.
Cheese-making trials revealed a distinct impact of SMARTMILK on microbial populations compared to HTST, being the former very effective to inhibit B. cereus, moulds and yeast but not psycrothrophic bacteria. SMARTMILK treatment influenced total protein content as this was lower in treated milk, curd and cheeses during ripening. A lower salt content was also observed. Accumulation of lactic acid during ripening was lower in SMARTMILK that reflected the lower consumption rate of lactose. Citrate was mainly consumed during ripening in SMARTMILK cheeses while levels of butyric acid, and particularly ethanol, were higher, confirming a different impact of HTST and SMARTMILK on microbial composition as noted above. Overall, SMARTMILK cheeses showed the most complex volatile compounds profile in which unusual ones such as 1-methyl 1,3 dioxolane and 1,3 dioxolone were detected. Perhaps, they are responsible for certain metallic odour detected in milk subjected to SMARTMILK treatment. As described for milk, SMARTMILK also changed the colour of curd (?E* between SMARTMILK curd and raw milk curd was 4.8285 compared with 0.61 between HTST and raw milk curd) and cheeses, and also influenced texture as SMARTMILK cheeses had lower hardness and adhesiveness than raw and HTST cheeses. Finally, it was noticed that cheese yield was slightly higher when MST-PEF milk was used for cheese making. A detailed report on task 5.3 can be found in D5.2.
Regarding yoghurt manufacture, the initial increase of milk pH after the SMARTMILK slowed down fermentation that took 8 h to reach the desirable pH. Nevertheless, both starter strains developed well on SMARTMILK milk and similarly to thermal milk. As observed before, thermal treatment was more effective than SMARTMILK in inactivating the initial microbial load although total viable counts followed a similar trend in during storage at 5 degrees of Celsius. As revealed by a distinct evolution of sugar and organic acids, the impact of SMARTMILK on the microbiota appeared to be different compared with the thermal treatment. Lactose was consumed quicker in SMARTMILK yoghurt along with citrate and orotic acid but, overall, less lactic acid was produced. On the contrary, butyric acid accumulated greatly only in SMARTMILK yoghurts. The galactose content was lower in SMARTMILK yoghurts enhancing their nutritional value. On the other hand, SMARTMILK yoghurt was less acid throughout storage and no major differences were observed in gross composition besides those already noticed in the previous experiments as the reduction of total solids and lower total protein content. Yoghurts made with SMARTMILK milk showed higher concentrations of these volatile compounds at the end of fermentation and during cold storage. Of note, acetaldehyde the volatile compound that gives yoghurt its characteristic flavour, was detected in thermal yoghurt recently fermented but decreased afterwards in contrast to SMARTMILK yoghurts. The milk treatment had a clear impact on the viscosity of yogurt. SMARTMILK yoghurt showed lower viscosity and a smoother texture than thermal yoghurt.
The technology was demonstrated internally to the consortium members at different stages of development, as well as to a wider audience through two open demonstration sessions at CSIC and IRIS, in Spain.
The SMARTMILK project has taken the development to pre-competitive level, however further scale up work and demonstration effort is required now in a post-project phase, especially as SMARTMILK proposes to position itself as a viable alternative to milk pasteurisation, to serve a niche market of dairy processors interested in serving an emerging demand among consumers for milk that has been treated with a milder alternative to pasteurisation. This post-project phase requires additional investment in order to bring the technology to full commercial scale for market exploitation.
Potential impact:
The SMARTMILK project has delivered to pre-competitive prototype scale a technology for treating whole milk, based on ultrasonication and PEF technologies for as an alternative to pasteurisation. A major feature of the system is that lower temperatures ensure that less thermal damage is delivered to the product. The results of the tests carried out at IPLA-CSIC facilities with the prototype indicated that the SMARTMILK system can be used as a tool to inactivate the microorganisms present in the raw milk. Moreover the potential for this system to be used in the treatment of other liquid products such as fruit juices, wine and beer is high, which enhances the exploitation possibilities of the SMARTMILK project results.
Since the ultrasonication and PEF results are highly dependent on the process parameters of these two technologies (e.g. the pulse width, pulse voltage, pulse frequency, US amplitude, US frequency and dwell time), such parameters need to be optimised to match the characteristics of the product to be treated, which requires further studies and development work. Some recommendations have also been given in terms of cleaning procedure, avoiding dead volumes, improving connectors and fittings, adding milk deposits, insulation of temperature sensors, energy savings.
There are numerous socio-economic impacts that will be derived from the results of this SMARTMILK research project. These impacts provide a core message for SMARTMILK dissemination activities to industry, the general public, governments and policy makers.
Each year in Europe some 24 million cows on over 1 million farms produce approximately 150 billion litres of raw milk, of which 138 billion litres are delivered to dairies and channelled into a broad range of products, both for consumption and for application in the production of many food, feed and pharma products. The various dairy products produced by the European dairy industry, such as liquid milk, cheese, fresh dairy products and butter, milk and whey powders and powdered infant formula (PIF), are an essential and functional contribution to the diet of all European consumers.
Europe is the largest exporter of dairy products in the world, even excluding intra-EU trade. World trade in dairy products is concentrated in cheese, butter and milk powder. However, in terms of growth of exports, New Zealand surpasses the EU. In recent years, world market growth coupled with the European Common Agriculture Policy (CAP) quota restrictions has mainly benefited New Zealand. Consequently, over the years the EU has quickly lost market share in the global trade.
As part of a move towards a market-driven CAP, the dairy industry is currently undergoing a transition from high regulation to domestic and international liberalisation. The dismantling of the milk delivery quota system by 2015, should see an additional 9 bn litres of milk per annum being produced in the EU, leading to greater processing opportunities. Against such a backdrop, it is a priority that a significant proportion of dairy output is linked to value added food products, such as bottled milk that meets consumer demands for taste, quality and nutritional profile, cheese, functional yoghurts, PIF, whey powders, nutritional supplements, etc. Successful capture of a greatly-expanded milk pool in this way is predicated upon the achievement of best-in-class performance by EU milk producers and processors who will face strong international competition in obtaining markets for their products.
Central to the expected socio-economic impacts, is the boosting of the competitiveness of companies operating along the dairy chain- from farm to glass- by improving the availability and quality of European milk. In this context, a number of key indicators for the dairy production sector alone are:
in 2005, there were a total of 13 000 enterprises across the EU-27 whose main activity was the manufacture of dairy products;
- the European dairy products manufacturing sector generated EUR 17.7 billion of value added in 2005, equivalent to 8.9 % of the value added generated by food, beverages and tobacco manufacturing activities in 2005;
- the largest dairy products manufacturing sectors in terms of value added generated were found in France (EUR 3.2 billion), Germany (EUR 2.6 billion) and Italy (EUR 2.5 billion); together these three Member States contributed just under half (48.1 %) of the EU-27's value added;
- the dairy products manufacturing sectors of the United Kingdom and Spain were also relatively large; they accounted for a combined 18.4 % of EU-27 output in 2005;
- on average, the dairy products manufacturing sector contributed 0.3 % to total value added within the EU-27's non-financial business economy in 2005;
- each person employed within the EU-27's dairy products manufacturing sector generated an average of 44 300 euro of value added in 2005.
Developments such as SMARTMILK offer enormous opportunity to create added value, novel offering and market differentiation, to contribute to increasing the competitiveness of dairy processing SMEs, as well as European manufacturers and suppliers of dairy equipment. Dairy producers who adopt the SMARTMILK system will be in a position to respond to consumer demand for high quality milk and dairy products. This heightened quality, if well communicated to consumers will increase consumer confidence and demand for dairy products that have undergone a milder treatment, which will translate into a competitive advantage for European dairy producers.
The consortium is confident that SMARTMILK could contribute to improve the quality of life, health and safety of European citizens, as well as provide a high food protection. However, firstly, the precompetitive results of this project require further development and demonstration work towards the industry.
A key importance was given to the management of the intellectual properties and in agreement of the dissemination of non-confidential information throughout the project. A preliminary business plan, as well as a post project development word, has been laid out. The synergistic role of the partners covering the whole supply and value chain has been discussed.
Finally successful dissemination activities have been carried out on the principles of the SMARTMILK technology, through the project website, a number of technical articles and attendance to conferences and trade fair both in industry and in the public domain and generating positive feedback. The impact of the dissemination activities that have been carried out during the project have been measured in order to gauge their effectiveness based on quantitative and qualitative indicators.
Number of industry visitors at trade shows and exhibitions: Over 2 000 companies and 300 000 professionals at the exhibitions visited the events at which SMARTMILK was exhibited.
Number of articles published: 5 in food-specialised magazines, 24 in the SMARTMILK website, 57 in partners' websites:
Number of papers submitted: 3
Number of posters and oral presentations in conferences: 3
Number of consultations from research community: 5
Number of face to face meetings: 25
Number of policy makers reached: 5
Number of press releases and articles published in the press: 6
Number of hits on the project website: 2.005
Followers on social media networks: 125
Project website: http://www.smartmilk.eu
SMARTMILK was a two-year applied research project, which commenced in October 2010 and finished in December 2012, and was funded under the 'Research for Small and medium-sized enterprise (SME)s' programme of the European Commission (EC)'s Seventh Framework Programme (FP7).
The European Union (EU) dairy industry produces 130 billion litres of raw milk each year for consumption and for application in the production of many food, feed and pharma products. Without doubt the quality and safety of milk and milk products is of paramount importance for safeguarding the health and safety of EU consumers. Pasteurisation of milk is very simple and effective in eliminating disease-causing germs, as it kills bacteria, yeast and fungi by heating the product. However, due to its high temperatures, pasteurisation damages heat labile compounds, significantly changing the taste of the final product and reducing the levels of vitamins and bioactive compounds. Clear market value would be derived by providing milk producers with an alternative milk treatment technology to pasteurisation that retains some of the beneficial components and natural flavours of milk, while ensuring quality and safety for consumers.
To this end, the SMARTMILK projects aimed at developing a technology that required milder treatment conditions, to substantially reduce the severity of the time / temperature exposure, while achieving similar shelf life to the conventional treatment. SMARTMILK combines pulsed electric field (PEF), with moderate heat and pressure - manothermosonication (MTS), to achieve a degree of inactivation of microorganisms comparable with conventional pasteurisation. The combination of PEF and MTS exploits the ability of the two technologies to act in a synergistic manner against the microbial population. This treatment employs milder conditions compared to pasteurisation resulting in a lesser degree of thermal damage to the milk.
The developers of SMARTMILK were committed to making this system affordable, robust and easy to maintain. Achieving this makes the technology accessible to European dairy processors, whereby they will benefit from being able to differentiate their products. SMARTMILK enables milk processors to meet with growing trends amongst consumers for milk that is safe but which retains more of the natural and taste characteristics of raw milk, while offering comparable shelf-life, along with enhanced nutritional and quality attributes compared to pasteurisation. The impact of the results also holds benefits for consumer safety and confidence, which will in turn impact on the competitiveness of thousands of European milk processing SMEs.
Project context and objectives:
Pasteurisation of milk is very simple and effective in eliminating disease-causing germs, as it kills bacteria, yeast and fungi by heating the product. However, due to its high temperatures, pasteurisation damages heat labile compounds, significantly changing the taste of the final product and reducing the levels of vitamins and bioactive compounds.
Due to its higher proportion of beneficial microorganisms and vitamins, and natural taste, an increasing number of consumers have expressed interest in drinking unpasteurised or raw milk. Clear market value would be derived by providing milk producers with an alternative milk treatment technology to pasteurisation that retains some of the beneficial components and natural flavours of milk, while ensuring quality and safety for consumers.
The SMARTMILK project aimed at developing milder treatment conditions, to substantially reduce the severity of the time / temperature exposure, while achieving similar shelf life to the conventional treatment. The overall objective of this project was to develop and build a precompetitive milk treatment system based on the novel combination of MTS and PEF technologies, as well as to test and validate the performance of the system for the effective treatment of milk and to compare the results with conventional pasteurisation treatment.
The specific objectives can be summarised as follows:
1. to use the results of a 'bottom-up' research approach to gain a understanding of the industrial needs and define the specifications of the SMARTMILK system;
2. to ensure the microbial effectiveness of the proposed combined MTS / PEF technology by carrying out laboratory trials;
3. to optimise the operating parameters of the combination of MTS and PEF to maximise the microbial inactivation while minimising the degree of thermal damage in the milk;
4. to define the parameters for the upscale of the laboratory results;
5. to draw up industrial designs for the SMARTMILK precompetitive prototype in keeping with specifications defined in WP1 and the parameters defined in WP2;
6. to build a precompetitive SMARTMILK prototype following the designs from objective 3 above;
7. to install, test and validate the SMARTMILK system in a real industrial environment;
8. to carry out quality tests on milk that has been treated with the SMARTMILK system and to compare them with milk treated using conventional treatments;
9. to evaluate and validate SMARTMILK treated milk for the processing of cheese and yoghurt;
10. to carefully outline scaling-up rules and development work for full production;
11. to facilitate the uptake of the SMARTMILK results by the participating SMEs, as well as by a wider audience, by carrying out demonstration activities.
The overriding goal of this project was to ensure that the pre-competitive SMARTMILK prototype resulting from this project fulfils the threshold requirements to ensure its further development post-project into a fully industrial system that is taken to market.
Project results:
The project started by understanding the technological and market needs of the European dairy industry in WP1. To do this, a questionnaire-based on-line survey directed to milk processors, cheese-makers, yoghurt manufacturers and dairy equipment providers was implemented. The survey was sent to approximately 750 dairy industries across Europe. In addition, in-depth consultations were conducted with a selected group of industry stakeholders. In total ten on-site visits were made to sites in Spain and Ireland. Furthermore, a literature, legislation and patent review was carried out. Outputs from this WP were used to define the desired industrial specifications of the SMARTMILK system.
In parallel to the previous work package, experimental procedures aimed at establishing the ability of the two individual technologies (MTS and PEF) to inactivate microorganisms of concern (or surrogates of them) for the milk industry were performed in WP2. E. coli and Pseudomonas were inactivated to a comparable level to conventional pasteurisation, though the gram+ organism (S. aureus) was inactivated to a slightly lesser extent than in heat processing (a phenomenon about gram+ organisms (most likely due to the thicker peptidoglycan layer in their cell membrane) which has also been noted by other workers). Other additional work which was included was the potential for paired combinations of PEF and US to inactivate Mycobacterium smegmatis (a non-pathogenic surrogate for M. tuberculosis).
Following this work, several operating parameters conditions for a combined MTS/PEF approach were tested and optimised to ensure effective microbial inactivation while minimising the thermal damage to the product. No differences were found in pH, conductivity or macro composition. In terms of colour the US / PEF treated milk was lighter and yellower than conventional pasteurised milk. The US / PEF treatments also had smaller emulsion particle sizes compared to conventional pasteurised milk (which was most likely due to the homogenisation of the milk by ultrasound). Vitamins B2 and B3 were not affected by the PEF / US treatments though B1 was reduced at more severe treatments. Native flora were inactivated to a comparable extent in milk which has been homogenised though in non-homogenised milk, comparable inactivation to pasteurisation was only observed under the most severe (i.e. HH) energy conditions. In terms of sensory evaluation, panellists could find no difference between raw, pasteurised or US/PEF processed milk in terms of colour intensity, liking the colour, consistency and transparency. They noted that the conventionally pasteurised and raw milk displayed higher clinginess to the cup (most likely due to the fact that they were less homogenised). However, panellists preferred the aroma of the raw and conventionally pasteurised and found the aroma intensity of the US / PEF treated to be higher.
TVC, Psychrotrophs, Pseumonads, Lactobacilli, Enterococci, Staphlococcus aureus and yeasts and moulds were examined from a microbial perspective while the enzymes alkaline phosphatase and lactoperoxidase were also assessed. From a microbial perspective, all treatments reduced the microbial load compared to untreated milk. US / PEF at higher temperatures was generally comparable to conventional pasteurisation. Similarly with enzymes, US / PEF generally produced comparable inactivation to conventional pasteurisation. The evolution of physical and chemical properties over shelf life was also compared to conventionally heat treated. Overall, in terms of shelf life, US / PEF treated were comparable to heat treated products.
WP2 concluded by defining a range of processing parameters (e.g. PEF field strength, cell geometry, pulse width and US power output, temperature regulation and processing chamber) necessary to perform a scale up of the equipment.
The SMARTMILK technology was scaled up during the second period of the project in order to build a pre-competitive prototype that could treat fresh milk-as an alternative to the traditional pasteurisation- by a synergistic combination of ultrasonication and PEF treatments. The prototype SMARTMILK unit served to prove the concept in industrial conditions; however it is not suitable for systematic industrial exploitation. It was designed in a modular fashion to allow for flexibility for tests / improvements and, simultaneously, to provide safe operation in moderate harsh environments. The system is based on a circuit for continuous circulation of the milk through the ultrasonication and the PEF chambers. It comprises not only these chambers, but also an ultrasound power generator, a pulse forming network, a high voltage power supply, a refrigeration unit, a peristaltic pump and a control unit. These elements are contained in a robust housing, which can be easily transported and used in typical industrial dairy plants.
The functionality of the prototype system was tested and the technology validated in the pilot plant facilities of CSIC in Spain, for the treatment of milk, as well as for suitability for cheese-making and yoghurt manufacture.
Milk shelf-life assays (5 degrees Celsius, 12 days) with SMARTMILK treated milk were compared with HTST pasteurisation (72 degrees Celsius, 15 s). SMARTMILK was slightly less effective than HTST to decrease the total viable counts (TVC), although a similar trend throughout the storage period was observed. Of note, SMARTMILK was able to inhibit the outgrowth of Bacillus cereus spores while HTST was not. SMARTMILK initially increased the pH of milk and it was kept slightly below HTST milk during storage. A 6 % decrease in total solids was detected in SMARTMILK milk mostly due to a decrease of the protein fraction. SMARTMILK did not alter the overall gross composition of milk. The main difference in the volatile profile was noticed at the end of the storage mainly due to the presence of ethanol in HTST milk that was absent in SMARTMILK. Interestingly, the availability of ionic calcium was higher in MTE-PEF milk than in HTST. This result suggests that it would not be necessary to supplement SMARTMILK milk with CaCl2 for cheese making as it is usual for cheese manufacture with HTST milk. The coagulation ability of SMARTMILK was similar or even higher than that of raw milk but it varies greatly depending on the flow rate during the SMARTMILK treatment. At the conditions tested, SMARTMILK clearly affected milk colour. In fact, the CIELAB colour difference ?E* between SMARTMILK and raw milk was 2.2303 compared with 0.3103 between HTST and raw milk. SMARTMILK treatment also exerted a sort of homogenisation as no cream layer developed during storage. A detailed report on tasks 5.1 and 5.2 can be found in D5.1.
Cheese-making trials revealed a distinct impact of SMARTMILK on microbial populations compared to HTST, being the former very effective to inhibit B. cereus, moulds and yeast but not psycrothrophic bacteria. SMARTMILK treatment influenced total protein content as this was lower in treated milk, curd and cheeses during ripening. A lower salt content was also observed. Accumulation of lactic acid during ripening was lower in SMARTMILK that reflected the lower consumption rate of lactose. Citrate was mainly consumed during ripening in SMARTMILK cheeses while levels of butyric acid, and particularly ethanol, were higher, confirming a different impact of HTST and SMARTMILK on microbial composition as noted above. Overall, SMARTMILK cheeses showed the most complex volatile compounds profile in which unusual ones such as 1-methyl 1,3 dioxolane and 1,3 dioxolone were detected. Perhaps, they are responsible for certain metallic odour detected in milk subjected to SMARTMILK treatment. As described for milk, SMARTMILK also changed the colour of curd (?E* between SMARTMILK curd and raw milk curd was 4.8285 compared with 0.61 between HTST and raw milk curd) and cheeses, and also influenced texture as SMARTMILK cheeses had lower hardness and adhesiveness than raw and HTST cheeses. Finally, it was noticed that cheese yield was slightly higher when MST-PEF milk was used for cheese making. A detailed report on task 5.3 can be found in D5.2.
Regarding yoghurt manufacture, the initial increase of milk pH after the SMARTMILK slowed down fermentation that took 8 h to reach the desirable pH. Nevertheless, both starter strains developed well on SMARTMILK milk and similarly to thermal milk. As observed before, thermal treatment was more effective than SMARTMILK in inactivating the initial microbial load although total viable counts followed a similar trend in during storage at 5 degrees of Celsius. As revealed by a distinct evolution of sugar and organic acids, the impact of SMARTMILK on the microbiota appeared to be different compared with the thermal treatment. Lactose was consumed quicker in SMARTMILK yoghurt along with citrate and orotic acid but, overall, less lactic acid was produced. On the contrary, butyric acid accumulated greatly only in SMARTMILK yoghurts. The galactose content was lower in SMARTMILK yoghurts enhancing their nutritional value. On the other hand, SMARTMILK yoghurt was less acid throughout storage and no major differences were observed in gross composition besides those already noticed in the previous experiments as the reduction of total solids and lower total protein content. Yoghurts made with SMARTMILK milk showed higher concentrations of these volatile compounds at the end of fermentation and during cold storage. Of note, acetaldehyde the volatile compound that gives yoghurt its characteristic flavour, was detected in thermal yoghurt recently fermented but decreased afterwards in contrast to SMARTMILK yoghurts. The milk treatment had a clear impact on the viscosity of yogurt. SMARTMILK yoghurt showed lower viscosity and a smoother texture than thermal yoghurt.
The technology was demonstrated internally to the consortium members at different stages of development, as well as to a wider audience through two open demonstration sessions at CSIC and IRIS, in Spain.
The SMARTMILK project has taken the development to pre-competitive level, however further scale up work and demonstration effort is required now in a post-project phase, especially as SMARTMILK proposes to position itself as a viable alternative to milk pasteurisation, to serve a niche market of dairy processors interested in serving an emerging demand among consumers for milk that has been treated with a milder alternative to pasteurisation. This post-project phase requires additional investment in order to bring the technology to full commercial scale for market exploitation.
Potential impact:
The SMARTMILK project has delivered to pre-competitive prototype scale a technology for treating whole milk, based on ultrasonication and PEF technologies for as an alternative to pasteurisation. A major feature of the system is that lower temperatures ensure that less thermal damage is delivered to the product. The results of the tests carried out at IPLA-CSIC facilities with the prototype indicated that the SMARTMILK system can be used as a tool to inactivate the microorganisms present in the raw milk. Moreover the potential for this system to be used in the treatment of other liquid products such as fruit juices, wine and beer is high, which enhances the exploitation possibilities of the SMARTMILK project results.
Since the ultrasonication and PEF results are highly dependent on the process parameters of these two technologies (e.g. the pulse width, pulse voltage, pulse frequency, US amplitude, US frequency and dwell time), such parameters need to be optimised to match the characteristics of the product to be treated, which requires further studies and development work. Some recommendations have also been given in terms of cleaning procedure, avoiding dead volumes, improving connectors and fittings, adding milk deposits, insulation of temperature sensors, energy savings.
There are numerous socio-economic impacts that will be derived from the results of this SMARTMILK research project. These impacts provide a core message for SMARTMILK dissemination activities to industry, the general public, governments and policy makers.
Each year in Europe some 24 million cows on over 1 million farms produce approximately 150 billion litres of raw milk, of which 138 billion litres are delivered to dairies and channelled into a broad range of products, both for consumption and for application in the production of many food, feed and pharma products. The various dairy products produced by the European dairy industry, such as liquid milk, cheese, fresh dairy products and butter, milk and whey powders and powdered infant formula (PIF), are an essential and functional contribution to the diet of all European consumers.
Europe is the largest exporter of dairy products in the world, even excluding intra-EU trade. World trade in dairy products is concentrated in cheese, butter and milk powder. However, in terms of growth of exports, New Zealand surpasses the EU. In recent years, world market growth coupled with the European Common Agriculture Policy (CAP) quota restrictions has mainly benefited New Zealand. Consequently, over the years the EU has quickly lost market share in the global trade.
As part of a move towards a market-driven CAP, the dairy industry is currently undergoing a transition from high regulation to domestic and international liberalisation. The dismantling of the milk delivery quota system by 2015, should see an additional 9 bn litres of milk per annum being produced in the EU, leading to greater processing opportunities. Against such a backdrop, it is a priority that a significant proportion of dairy output is linked to value added food products, such as bottled milk that meets consumer demands for taste, quality and nutritional profile, cheese, functional yoghurts, PIF, whey powders, nutritional supplements, etc. Successful capture of a greatly-expanded milk pool in this way is predicated upon the achievement of best-in-class performance by EU milk producers and processors who will face strong international competition in obtaining markets for their products.
Central to the expected socio-economic impacts, is the boosting of the competitiveness of companies operating along the dairy chain- from farm to glass- by improving the availability and quality of European milk. In this context, a number of key indicators for the dairy production sector alone are:
in 2005, there were a total of 13 000 enterprises across the EU-27 whose main activity was the manufacture of dairy products;
- the European dairy products manufacturing sector generated EUR 17.7 billion of value added in 2005, equivalent to 8.9 % of the value added generated by food, beverages and tobacco manufacturing activities in 2005;
- the largest dairy products manufacturing sectors in terms of value added generated were found in France (EUR 3.2 billion), Germany (EUR 2.6 billion) and Italy (EUR 2.5 billion); together these three Member States contributed just under half (48.1 %) of the EU-27's value added;
- the dairy products manufacturing sectors of the United Kingdom and Spain were also relatively large; they accounted for a combined 18.4 % of EU-27 output in 2005;
- on average, the dairy products manufacturing sector contributed 0.3 % to total value added within the EU-27's non-financial business economy in 2005;
- each person employed within the EU-27's dairy products manufacturing sector generated an average of 44 300 euro of value added in 2005.
Developments such as SMARTMILK offer enormous opportunity to create added value, novel offering and market differentiation, to contribute to increasing the competitiveness of dairy processing SMEs, as well as European manufacturers and suppliers of dairy equipment. Dairy producers who adopt the SMARTMILK system will be in a position to respond to consumer demand for high quality milk and dairy products. This heightened quality, if well communicated to consumers will increase consumer confidence and demand for dairy products that have undergone a milder treatment, which will translate into a competitive advantage for European dairy producers.
The consortium is confident that SMARTMILK could contribute to improve the quality of life, health and safety of European citizens, as well as provide a high food protection. However, firstly, the precompetitive results of this project require further development and demonstration work towards the industry.
A key importance was given to the management of the intellectual properties and in agreement of the dissemination of non-confidential information throughout the project. A preliminary business plan, as well as a post project development word, has been laid out. The synergistic role of the partners covering the whole supply and value chain has been discussed.
Finally successful dissemination activities have been carried out on the principles of the SMARTMILK technology, through the project website, a number of technical articles and attendance to conferences and trade fair both in industry and in the public domain and generating positive feedback. The impact of the dissemination activities that have been carried out during the project have been measured in order to gauge their effectiveness based on quantitative and qualitative indicators.
Number of industry visitors at trade shows and exhibitions: Over 2 000 companies and 300 000 professionals at the exhibitions visited the events at which SMARTMILK was exhibited.
Number of articles published: 5 in food-specialised magazines, 24 in the SMARTMILK website, 57 in partners' websites:
Number of papers submitted: 3
Number of posters and oral presentations in conferences: 3
Number of consultations from research community: 5
Number of face to face meetings: 25
Number of policy makers reached: 5
Number of press releases and articles published in the press: 6
Number of hits on the project website: 2.005
Followers on social media networks: 125
Project website: http://www.smartmilk.eu