Emerging applications for food system sustainability. UVC shows potential for improving quality and...

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Emerging Applications for Food

System Sustainability:

UVC Shows Potential for Improving

the Quality and Safety of Liquid Dairy

Products

Gail Barnes Ph.D. M.B.L.

Personify LLC

IFT International Food Nanoscience Conference

July 12-13 ▪ Hilton Chicago ▪ Chicago, IL USA



Summary UV light in the range of 200 - 280 nm (UVC) inactivates

pathogens as a result of the absorption of the UV light by the nucleotides of DNA molecules

The nucleotides are dimerized by UVC and the subsequent chemical modification prevents DNA replication and transcription

This presentation will explore the significance of the germicidal effect of UVC for processing liquid dairy products in both developing and developed markets, on its potential to improve raw milk quality, and address food safety issues around soft cheeses

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How UV Illumination Works The killing spectrum of UV light

coincides with the peak absorbance of DNA for UV light, suggesting that DNA is the key macromolecule that is damaged

UV light causes dimerization of 2 adjacent thymine pyrimidine bases

2 forms of the dimer • Cyclobutane dimer • 6-4 photoproduct

Both DNA lesions are bulky and distort the double helix

Thymine dimers block transcription and replication, and are lethal unless repaired

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Dimerization Of Adjacent Pyrimidine Bases

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UV Illumination & Extended Shelf Life

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Raw Milk Refrigerated Storage & Distribution

Environmental factors Operational factors

Mic

rob

iolo

gica

l C

ou

nt

Shelf Life Pasteurized

Processing Packaging

ESL

UV

Pre-Treatment

UV + Pasteurization

Post-Treatment

Pasteurization

Recontamination

Ultra-pasteurization

18-21 days if distributed & stored at 4o C

60- 90+ days if filled & packaged with ESL filler &

distributed & stored at 4o C



Food Safety Studies Food safety potential of UV illumination has been validated by

studies at the University of California-Davis in Tulare and the

California Polytechnic State University in San Luis Obispo

UV resistance and D-values have been established for gram

positive spore forming bacteria and the pathogens E. coli

0157:H7, Salmonella enterica serovar Senftenberg, Yersinia

enterolitica, Staphylococcus aureus, Campylobacter jejuni,

Serratia marcescens, Aeromonas hydrophila, and Listeria

monocytogenes

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Source Professor Jim Cullor, University of California-Davis, presentation at 3rd International Symposium on Mastitis and Milk Quality in conjunction with the American Association of Bovine Practitioners (AABP) , 44th Annual Conference, September 22-24, 2011, St. Louis, Missouri



Shelf Life Studies Thermo tolerant spoilage organisms do survive pasteurization

restricting the shelf life or products as evidenced by code dates of 14 to

18 days

• Spoilage organisms include Gram positive, Gram negative and aerobic spore-

forming bacteria of the genera Bacillus, Paenebacillus, and Geobacillus

• These spores can and do survive pasteurization, germinate, multiply and can

cause spoilage in milk and milk products after processing

In laboratory studies by University of California-Davis on milk with 3.5%

and 2% fat, UV illumination as an adjunct to pasteurization has been

shown to increase microbial shelf life by 28 to 35 days

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Source Professor Jim Cullor, University of California-Davis, presentation at 3rd International Symposium on Mastitis and Milk Quality in conjunction with the American Association of Bovine Practitioners (AABP) , 44th Annual Conference, September 22-24, 2011, St. Louis, Missouri



Benefit To Producers UV illumination as an adjunct to pasteurization could provide for better

maintenance of the quality of milk and as such could lead to improved sales Milk with an added measure of quality will make milk more available to the

consumer as it will allow distribution of both white milk as well as smaller volume higher margin products into areas of the retail trade where distribution has been limited because of shelf life

UV illumination of raw milk can improve risk of consumption of non-pasteurized cheeses in North American dairy markets • According to a joint risk assessment drafted by the U.S. Food and Drug Administration and

Health Canada, consumers are up to 160 times more likely to contract a Listeria infection from soft-ripened cheese made from raw milk compared to the same cheese made with pasteurized milk

UV illumination for pre-treatment of raw milk can be used as alternative thermisation method in developing markets where lack of a reliable energy supply and high cost make on farm refrigeration prohibitive • Allow controlling microorganisms and the storage of milk for prolonged periods

• Due to its “cold” nature, improve milk quality and reduce losses

• Extend shelf-life during transportation to milk processing centers

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Benefit To Processors Energy efficiency improvements in milk processing plants are limited by

the energy requirements of heat-based pasteurization, which includes heating and cooling milk

Non-thermal processes, such as UV illumination, used as an adjunct to pasteurization, have the potential to cut demand for energy for ultra-pasteurization of ESL products

The result will be longer shelf life, higher-quality milk products produced using less energy, and with lower GHG emissions, waste and associated costs

Amylase, catalase, lactase, lactoferrin, lipase, phosphatase, protein, vitamin A that are easily destroyed by heat remained intact after UV processing

The trace of fat-soluble vitamin D found naturally in milk can be enhanced by UV processing

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Thermal / UV Energy Evaluation

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0100200300400500600700

Energy in MJ/tPast. 430

Past. + UV 484

UHT 685

Sources G. Riva, Institute of Agricultural Engineering, University of Milan, Italy. Utilization of renewable energy sources and energy-saving technologies by small-scale milk plants and collection centers., FAO ANIMAL PRODUCTION AND HEALTH PAPER 93. Technology supplier.



Legislative Status in U.S. The University Of California-Davis submitted a proposal to NCIMS 2011 for

a change to the Pasteurized Milk Ordinance (PMO) that would allow commercial production of milk with UV illumination as an adjunct to pasteurization • The original proposal was not accepted but an amended proposal was which was that a

study group be appointed to oversee further food safety studies in the area of furans and cholesterol oxides amongst other compounds

• These studies were to be conducted under the chairmanship of Dr Steve Beam of the California Department of Food and Agriculture

The acceptance of UV illumination as a food additive under 21 CFR 179.39(b) (1) is being addressed by technology suppliers with the department that deals with the standards of identity for milk

Based on information from Pennsylvania State University, labeling of the UV product may not be necessary • “Federal law does not require that product that has been treated by pasteurization,

ultraviolet light or ozonation be labeled to identify the treatment process. (Reference: 21 CFR §179.39 (ultraviolet); §173.368 (ozone).)”

• Technology suppliers are in discussion with the FDA on this opinion

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Personify LLC

[email protected]

+1 650 218 4993

@DrGailB / @ZAGrrl

Gail Barnes Ph.D. M.B.L.

mailto:[email protected]

Emerging applications for food system sustainability. UVC shows potential for improving quality and...

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