Core areas of expertise:

• Physical properties of foods
• Food processing operations
• Milk and milk processing
• Heat treatment, evaporation, drying and membranes.

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Areas of expertise

Raw milk quality
• Solve issues relating to chemical composition, such as proteins, carbohydrates, fats, minerals, vitamins and trace nutrients • Protect production line output from environmental or process plant contaminants • Ensure reliable low microbial counts in both raw materials and final products. • Maintain high quality milk products free from pathogenic and spoilage bacteria

Pasteurisation, extended shelf-life products
• Understand the factors for ensuring a long shelf-life, such as raw milk quality, correct processing conditions, eliminating post-processing contamination and ensuring low temperature storage • Although pasteurisation is a well understood technology some producers are not able to maintain control leading to a wide range of problems. • Investigate shelf-life issues and persistent production line disruption due to over-pasteurisation, recontamination or other forms of damage due to process control problems. • Avoid unnecessary waste that damages profitable performance.

UHT and in-container sterilisation processes.
• High temperature sterilisation and short duration high-temperature UHT can create a number of product quality issues. • Solve heat stability problems without creating new problems including gelation, age-thickening or changing flavour and other sensory characteristics of your product. • Over 35 years experience operating UHT pilot plant. Offering short courses and troubleshooting.

Evaporation and drying
• Retain control of the heat stability of your products. This is a fundamental requirement but not easy to achieve. Gain technological know-how and experience. • Ensure powder products have desirable physical and chemical properties and are free of pathogenic bacteria • Understanding how evaporator and dryer performance affect milk product quality • Ensuring these energy intensive operations have minimum impact on the carbon footprint of national and global supply chains.

Membrane separations
• Are you achieving best performance from your investment in membrane separation? • Is there a place for membrane operations in your company

Calcium & mineral fortification
• Dr Lewis is an acclaimed international expert on minerals in milk and the measurement of ionic calcium (see below) • Claims about calcium and mineral fortification can add value and prestige to your products. • As a current focus of research and development, Dr Lewis can ensure your team have a deeper understanding of the nutritional and technological aspects of calcium in dairy products.

Ionic calcium measurement in milk
• The measurement of ionic calcium in milk and milk products is of vital importance in understanding the role of calcium in milk. Despite the ultimate commercial benefits that can arise from knowing this characteristic ionic calcium is not widely measured in the diary industry. • Are you aware of the potential commercial advantage this measurement capability can add to your products? • Helping you get started to measure ionic calcium in milk • Understanding how variations in milk from cows and goats or bulk milk sources affect the quality of your products? • Knowing how the addition and removal of calcium and other salts, rennet coagulation, miscellaneous influences, filtration and evaporation relate to processing.

Heat stability
• Good quality milk usually has a good heat stability. However, when it is used in milk products, the resulting changes in pH and ionic calcium may adversely affect heat stability. • Benefit from improved heat stability of milk supplemented with calcium salts, fruit extracts, flavour compounds, stabilising salts and other permitted additives. • Understanding issues related to poor heat stability, such as fouling, sediment formation and cleaning issues

Methods for partitioning milk
• Membrane processes, such as dialysis, nanofiltration, ultrafiltration, microfiltration and dialysis • Ultracentrifugation and renneting • Partitioning at high temperature

Best use for milk
• Are you making the “best use for milk” in situations where this is possible? • The requirements of milk for cheese making are very different to those for making evaporated milk, milk powder or UHT milk. Problems can arise when using milk that is not appropriate for the intended product. • This is the study of a research project which is nearing completion at the University of Reading

Environmental issues
• International frontiers are disappearing as globalised supply chains reach out around the world. This interrelates businesses much more closely and one company’s bad practice may impact on others along the chain. Nowhere is this more evident than in the challenge to minimise the carbon footprint of food production. • Dr Lewis can supplement your knowledge of latest technology to enhance the quality of milk and dairy products and reduce the energy required. • Discover hidden factors about heat pumps and techniques for minimising water and energy wastage. • Apply Dr Lewis’ knowledge to comply with the most stringent food retailer’s energy requirements and protect profitability.

Properties of milk at high temperature
• Sterilisation and UHT can adversely affect the characteristics of your products and loose your customers. • Discover ways to use high temperature processes and stabilise the quality and character of your diary products.

Analytical procedures:
• Are you using appropriate analytical procedures to ensure milk safety and quality and do you personnel understand the significance of the experimental results? • Dr Lewis has a good insight into both simple and sophisticated analytical procedures

Thermodynamics of diary production
• Are you making the most of the thermodynamic properties of steam and refrigerants? • Are you utilising heat pumps and energy conservation best practice? • See how Dr Lewis can help you improve the efficiency of your temperature dependant processes.

Research presentations in wide range of topics
• Dr Lewis has been lecturing to students in the UK and Worldwide and has an internationally acclaimed reputation as being a very good teacher and communicator. • He is able to make presentations on a wide range of topics related to milk safety and quality and to ongoing developments in research and analytical procedures.

Physical properties of foods
• Dairy products have many physical attributes that need careful management to ensure consist quality and safety. These include density, specific heat, viscosity, rheological and electrical properties. Dr Lewis’s first book is titled the Physical Properties of Foods and Food Processing Systems Process development and improvement • Benefit from Dr Lewis’ broad experience with UHT processes and products. • Understand the issues relating to the role of raw material quality on various safety and quality attributes, and also on heat stability, fouling and sediment-related issues with heat-treated milk. • Deal more successfully with fouling and cleaning issues and how these affect raw material quality. • Dr Lewis can project manage pilot plant trials in liaison with the University of Reading Food & Nutritional Science and other appropriate education institutions. • Initiate new product and process developments with more confidence in the outcome. • Review safety and quality issues with current products and gain more insight into your future plans. Benefit from deep experience with concentration and membrane processes and drying procedures. • Improve environmental performance, review environmental issues and generate performance data and targets to benchmark improvements in water and energy utilisation, including refrigeration. • Find the right people to help complete your dairy R&D and processing functions.