Upload
gail-barnes
View
376
Download
5
Embed Size (px)
DESCRIPTION
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 explores 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.
Citation preview
Template graphic elements and format © 2013, Institute of Food Technologists.
All rights reserved. Slide content © 2013, by the presenter. All rights reserved.
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
Template graphic elements and format © 2013, Institute of Food Technologists.
All rights reserved. Slide content © 2013, by the presenter. All rights reserved.
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
Template graphic elements and format © 2013, Institute of Food Technologists.
All rights reserved. Slide content © 2013, by the presenter. All rights reserved.
Dimerization Of Adjacent Pyrimidine Bases
4
Template graphic elements and format © 2013, Institute of Food Technologists.
All rights reserved. Slide content © 2013, by the presenter. All rights reserved.
UV Illumination & Extended Shelf Life
5
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
Template graphic elements and format © 2013, Institute of Food Technologists.
All rights reserved. Slide content © 2013, by the presenter. All rights reserved.
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
6
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
Template graphic elements and format © 2013, Institute of Food Technologists.
All rights reserved. Slide content © 2013, by the presenter. All rights reserved.
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
7
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
Template graphic elements and format © 2013, Institute of Food Technologists.
All rights reserved. Slide content © 2013, by the presenter. All rights reserved.
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
8
Template graphic elements and format © 2013, Institute of Food Technologists.
All rights reserved. Slide content © 2013, by the presenter. All rights reserved.
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
9
Template graphic elements and format © 2013, Institute of Food Technologists.
All rights reserved. Slide content © 2013, by the presenter. All rights reserved.
Thermal / UV Energy Evaluation
10
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.
Template graphic elements and format © 2013, Institute of Food Technologists.
All rights reserved. Slide content © 2013, by the presenter. All rights reserved.
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
Template graphic elements and format © 2013, Institute of Food Technologists.
All rights reserved. Slide content © 2013, by the presenter. All rights reserved.
Personify LLC
+1 650 218 4993
@DrGailB / @ZAGrrl
Gail Barnes Ph.D. M.B.L.