The Milk Producer - October 2009 - (Page 35)

´ RESEARCH By Joey Sabljic Innovative concept Researchers use ultraviolet light technology to treat raw milk without sacrificing taste U niversity of Guelph researchers are trying to determine if a new, innovative way of using ultraviolet (UV) light technology could remove harmful bacteria from raw milk, while leaving its nutritional content and taste intact. Thermal pasteurization kills harmful bacteria in raw milk such as E. coli, Salmonella and Listeria. However, the process can affect taste and texture, and may affect certain proteins and nutrients. Department of food science professor Keith Warriner and food science master’s student Ting Ying are working with a Canadian company to develop a system that would remove harmful bacteria from raw milk by passing it through a UV light reactor. By doing so, they hope consumers could enjoy the milk without risking illness. “This is a big move away from thermal pasteurization because now we’ve got a process that makes it safe for people to drink (milk) without having to use heat treatment,” says Warriner. UV reactor technology has been used successfully to treat fruit juices and wastewater. Liquid is passed through a series of UV lamps that give off an intensely focused light that rapidly kills microbes. This ensures the milk is safe to drink and won’t spoil too quickly. However, opacity poses a major challenge to using UV technology in milk, unlike clear fluids such as water or juice. The UV light cannot penetrate milk’s opaque surface, similar to Researchers hope to create UV-treated milk that won’t cause illness. how sunscreen protects skin from UV rays. This is overcome by over-exposing milk to UV rays to ensure all the liquid is treated. However, if milk is left exposed to UV rays for too long, it can become discoloured and have a sulphurous smell. For raw milk to be completely decontaminated, it needs to be well mixed so UV rays reach every part of the milk without overdosing the system. That’s where the ultraviolet light reactor comes in. Warriner and his partners have created computer simulations of the reactor. It lets them design an efficient mixing mechanism, minimizing the UV dose required to kill microbes that can compromise raw milk’s safety and stability. Their research is focused on finding the ideal reactor design and best operating conditions. They plan to run trials to ensure the reactor can kill a wide range of microbes. As for commercial opportunities, Warriner says raw milk remains a controversial subject, since it is illegal to sell or distribute. However, with UV technology, its popularity could grow for uses such as soft cheese manufacturing, because raw milk provides a more delicate texture and richer flavour. “The fact is, any federal agency is very reluctant to stop thermally pasteurizing milk … it was introduced over 70 years ago, so change will be slow,” says Warriner. “But if the technology proves to be as effective as pasteurization, we could see UVtreated milk alongside pasteurized milk within the next 10 years.” Joey Sabljic´ is a student writer with the University of Guelph’s office of research. Others involved in the project include Dr. Tatiana Koutchma, Agriculture and Agri-Food Canada, Katrina Straathof, DFO scholarship recipient, and professors Guari Mittal, school of engineering and Milena Corredig, department of food science. The research receives support from the university’s partnership with the Ontario Ministry of Agriculture, Food and Rural Affairs, and the Ontario Centre of Excellence Materials and Manufacturing program. MilkPRODUCER | October 2009 | 35

Table of Contents for the Digital Edition of The Milk Producer - October 2009

The Milk Producer - October 2009
Contents
Editor's Notes
DFOVice-Chair's Message
Dairy Update
Industry Roundup
National Policy
DFC Promotion
Sinking In Stormy Seas
Processor Spotlight
Research
Applied Science
Ruminations
Markets
New 'N' Noted
Back Forty

The Milk Producer - October 2009