Emerging applications for food system sustainability. UVC shows potential for improving quality and safety of liquid dairy products.

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

Template graphic elements and format © 2013, Institute of Food Technologists.
All rights reserved. Slide content © 2013, by the presenter. All rights reserved.

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

2


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
3


Dimerization Of Adjacent
Pyrimidine Bases

4


UV Illumination & Extended Shelf
Life
Environmental factors

Microbiological
Count

Raw Milk

Processing

Operational factors
Packaging Refrigerated Storage & Distribution

Pasteurization
UV
Pre-Treatment

Recontamination
Ultra-pasteurization

UV +
Pasteurization
Post-Treatment

Shelf Life

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

5


ESL
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

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
6


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 sporeforming 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
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

7


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 nonpasteurized 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

8


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 ultrapasteurization 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

9


Thermal / UV Energy Evaluation
700
600
500
400
300
200
100
0
Past.
Past. + UV
UHT

Energy in MJ/t
430
484
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.
10


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

11


Gail Barnes Ph.D. M.B.L.
Personify LLC
barnes.gail@gmail.com
+1 650 218 4993
@DrGailB / @ZAGrrl


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