A Process for Printing Activity to Food Contact Surfaces

NON-TECHNICAL SUMMARY: The reduction of disease causing organisms on food working surfaces and the reduction of microorganisms in packaged foods. Microbailly contaminated Food contact surfaces serve as reserviors for food poisoning. Suitably antimicrobial surfaces prevent the growth and spread of microorganisms thereby reducing food-borne disease.<P>

APPROACH: Energy curable resins will be flexographically printed to the food contact surface of packaging polymers. Silver zeolite or other active functionalities will be eletrostatically impressed into the uncured resin. The resin will be flash polymerized using either UV or ebeam energy. EPA test for surface sanitation will be performed to assess the suitablity of the process for food working surfaces. Innoculated pak studies will be performed to assess the competence of surface applications to inhibit microorganisms.<P>

PROGRESS: 2007/06 TO 2008/02<BR>

OUTPUTS: The activation method proposed examined in this work can be applied to address many of the safety and freshness issues encountered by the food supply on its way from the field to the table. These include but are not limited to producting foods: (1) Freer from pathogens, (2) more shelf stable, (3) tamper evident protected (4) thermal-abuse evident (5) less prone to bioterrorism (6) easier to handle (8) healthier/nutritious (8) more informative. Neither the concept nor the commercialization of active packaging is new. Development of antioxidant-impregnated cereal packages; oxygen scavenging packaging, and antimicrobial surfaces containing such compounds as silver zeolite and nicins have been offered to the food industry with greater or lesser commercial success. What has been needed is an inexpensive approach to applying activities. The concept of active printing as an inexpensive approach to surface activation received much of its preliminary thinking at Purdue University. In particular where manually applied enzyme/resin systems and viruses remained productively active following UV curing. The Phase I SBIR effort has further proven that printing, in this case of silver zeolite, produces an active surface equivalent to or better than the existing commercial paradigm. The idea has spawned a PhD thesis, several peer-reviewed papers, this SBIR and 3 additional grants from USDA, NIH and NASA with rely in part on the technology to achieve the deliverables of the grant.<BR>
PARTICIPANTS: The 9 month Phase I SBIR effort was headed directed by PROVE IT (packaging, regulation, optimization, validation and education for innovative technologies), under the immediate direction of it's CTO and Purdue Adjunct Professor, George Sadler. The work was undertaken at Purdue University in the lab of Mark Morgan, an Associate Professor of Agricultural Engineering. There was 1 technician assigned to the work. During the work, the approach was presented to a number of technical departments in the food industry. These include Coke, Pepsi, Cryovac, AEB irradiators, General Mills, Rapid Diagnostics, Chuck Sizer, LLC and others for commericalization opportunities. These all supplied letters to the Phase II effort. <BR>TARGET
AUDIENCES: The ultimate target audience for this technology is everyone who uses a packaging material. It is intended to be part of a general national effort to reduce food borne illness and to improve nutrition. It will be further beneficial by providing consumers with better status information about packaging on such issues as shelf life and thermal history. <BR>
PROJECT MODIFICATIONS: Inevitable experimental approaches for applying activities. However, there were fundamental changes in the approach from that promised in the Phase I work plan.
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IMPACT: 2007/06 TO 2008/02<BR>
The 9 month Surface Activation, Phase I proof of concept project immobilized several activities to polymer surfaces in a flexographically-printed UV-cured polymer matrix. Surface activation using this approach reserves all the advantages of UV-cured graphic printing technology including: The use of stock resins, the existence of commercial UV-cured flexographic printing equipment able to apply and cure resin at line speeds up to 100 meters per minute with the freedom to apply several resin layers with full curing in between each press roll. Combined, these advantages allow rapid and inexpensive surface activation and permit activities to be applied which depend on coupled or sequential reactions. The validation project promised in the Phase I was the flexographic printing of silver zeolite antimicrobial on a polyolefin polymer. The results show that surface-immobilized silver zeolite applied in commercial UV curable resins using a commercial flexographic printer is feasible and of comparable activity to the existing extruder-phase silver incorporation paradigm. While outside the scope of the original SBIR silver zeolite antimicrobial subject, flexographic printing of concepts previously examined at Purdue using a manual application method were examined to confirm activity still existed in print phase. These included glucose oxidase/peroxidase to remove oxygen and lactase to remove lactose from whole milk. The enzymes remained bound with retained activity ranging from 50 to 89% that of free enzyme. Concurrently, the active printing technology is being explored as part of NIH grant by another PI, to inactivate an Ecoli O157, H7 specific bacteriophage on the surface of stomacher bags. The bacteriophage have been genetically modified to produce phosphorescence in infected E coli. The viruses also bind the E. coli in such a way that the complex does not separate. This permanent attachment produces enrichment of E coli at stomacher bag surface. Enumeration of E coli then becomes possible using a photon camera. Two new applications of the technology were also developed as extracurricular efforts of the Phase I grant. These are the printing of an iron-containing oxygen scavenger and printing of a progress-toward-end-of-shelf-life indicator. Producing commercial versions of these 6 concepts (antimicrobial, ezymatic oxygen scavenger, lactose removing packaging, bacteriophage detection of E. Coli, chemical oxygen scavenger and end of shelf life indicator, would be the objective of a successful Phase II effort.