Science Platforms > RPPACKA

Food Packaging Completed Projects

PA-0002-10/92

Project Title: Assessing the Ability of PETE to Serve as a Functional Barrier to the Migration of Organic Compounds

Project Leader: G. Sadler, NCFST/IIT

Project Collaborators: V. Senthil, NCFST/IIT, S. Eskamini, NCFST/IIT, and S. Hussaini, NCFST/IIT

The objective of this study was to characterize the ability of a virgin layer of PETE to serve as a functional barrier to the migration of organic contaminants. Absorption concerns have caused the FDA to question the safety of recycled plastics. They fear contaminants acquired through post-consumer recycling abuses might result in dangerous levels of household chemicals absorbing into plastics and ultimately leaching into foods held in second generation containers. The FDA has issued guidelines to help resin recyclers determine if their resins are suitable for food use. FDA extractables testing can be used to empirically evaluate the migration rate of contaminants from plastics. The FDA has also described a mathematical approach for evaluating contaminant migration from plastics into food. The purpose of this research was to determine whether migration of contaminants from recycled PET would exceed the threshold of regulation and, if so, what thickness of virgin polymer would restrict migration to an acceptable level (a functional barrier).The surrogates officially selected for analysis were tetracosane, malathion, and butyric acid. Copper (11) 2-ethylhexanoate was used as a heavy metal surrogate. Benzene had the fastest permeation rate of all the surrogates. If benzene were allowed to absorb into a PET container for 2 weeks at 40°C and the container was cleaned, dried and remade into a 100% recycle content container, there would be 120 ppb contamination of the food supply. All other compounds would be present below the limit of detection. The approach appeared useful for estimating worst-case diffusion of model compounds into foods contained in PET containers.

PA-0003-10/92

Project Title: Accoustic Imaging of Defects in Shelf-stable Food Packages

Project Leader: H.J. Meerbaum, Dept. Of Food Science/UIUC

Project Collaborators: A.A. Safvi, Bioacoustics Research Laboratory, Dept. of Electrical and Computer Engineering, UIUC and S.A. Morris, Dept. Of Food Science/UIUC, C.L. Harper,NCFST/IIT, and O=Brien, Jr., Bioacoustics Research Laboratory, Dept. of Electrical and Computer Engineering, UIUC

The objective of the project was to determine the conditions under which a leak or seal defect can result in bacterial contamination or package integrity failure in a flexible plastic pouch. These results, combined with nondestructive defect detection techniques, will eventually be used to establish general guidelines for a real time, nondestructive, on-line system that will accurately evaluate package integrity. Newer food processing and packaging techniques include retortable pouches, "plastic cans" and aseptically packaged foods. Newer inspection techniques must be developed to address fundamental changes in food processing and packaging which compromise food safety by producing defects in the heat-seal portion of packages. In this study, channel defects were fabricated and then characterized and imaged using scanning laser acoustic microscopy (SLAM). SLAM uses sound waves to produce images. It has the ability to detect, classify and accurately reproduce the internal structure of opaque materials, and the defects contained therein. Ultrasound can be used to image flaws in opaque packaging materials. The results obtained here significantly exceeded expected results. A 10µm channel was detected using a SLAM (100MHz) with a 20 µm resolution. The resolution of the SLAM is inversely proportional to its frequency. Therefore, when the frequency is doubled, the resolution is halved. Thus, a 200 MHz SLAM should detect channels smaller than 10 µm.

PA-0005-10/93

Project Title: Assessing the Safety of Recycled Pulp for Direct Contact with Fatty and Aqueous Foods

Project Leader: G. Sadler, NCFST/IIT,

Project Collaborators: S. Eskamani, NCFST/IIT, H. Spirakes, NCFST/IIT

The objective of this project was to determine whether recycled pulp is safe for direct contact with fatty and aqueous foods. Current federal regulations (CFR 176.260) forbid direct contact between recycled pulp products and foods which are high in fat or moisture unless the absence of poisonous or deleterious materials can be shown. California's Safe Drinking Water & Toxic

Enforcement Act of 1986 (Proposition 65) has identified hundreds of carcinogens and reproductive toxicants which must be restricted to State proscribed "No Significant Risk Levels".

However, the presence of lead in recycled paperboard is known to exist at levels which would surpass the proposition 65 reproductive toxin restriction of 0.5µg/day assuming 100% migration into food. During the first year, analysis protocols were developed to quantify lead in paperboard and fatty and aqueous food extracts. The second and final year of the study found that recycled paperboard will not impart any meaningful level of lead to fatty or aqueous foods held in direct contact with paperboard containers filled and used at ambient temperature. It appears that lead migration concerns will scientifically, be a non-issue.

PA-0006-10/94

Project Title: Public Health Safety of Low-Acid Canned Foods(LACFs) in Pressurized Metal Containers

Project Leader: G. Sadler, NCFST/IIT and S. Hussaini, NCFST/IIT

The objective of this project was to provide recommendations that would preclude the erosion of public health safety associated with vacuum-packed cans, should underprocessing of a LACF in a pressurized can occur. FDA has questioned the safety factors involved when low acid foods are canned and stored in containers pressurized with an inert atmosphere of nitrogen. Application of this packaging technology for low-acid foods would greatly complicate the possibility of finding swelled containers as the usual warning sign of botulism. The variability of liquid nitrogen injections may produce a highly varied pressure background. This would make detection of a swollen can difficult to detect even with instrumental methods. The possibility of detecting gas production in pressurized cans by appropriate sensitive instruments such as that available from Ellab was evaluated for its effectiveness and sensitivity. Data collected up to the present suggests it is possible to detect a deflection difference 1 bar above background. Increased pressure due to botulinum swells could likely be identified at the warehouse stage of distribution using Ellab or other sensing equipment capable of detecting the 1 bar pressure increase. However, the consumer could still not identify a post-warehousing botulinum swell. Consequently, aluminum cans, as currently designed, will never provide equal protection against botulism as steel cans with vacuum headspace.

PA-0007-10/94

Project Title: Potential Migration of Residual Contaminants from Secondary Recycled PETE into the Food Supply - A Safety Assessment

Project Leader: V. Komolprasert, NCFST/FDA

Project Collaborators: A. Lawson, NCFST/IIT, T. Begley, FDA/CFSAN, A. Gregor, NCFST/IIT, G. Sadler, NCFST/IIT, W. Hargraves, NCFST/FDA, D. Armstrong, NCFST/FDA

The objective of this project was to measure the amount of residual contaminants in 2° recycled PETE which can migrate into a food simulating and/or a real food system during storage and use conditions. This project was an extension of the PETE recycling project which demonstrated that most surrogate contaminants still survive after washing and drying. These experiments are critical in determining whether the FDA=s 0.5 ppb threshold for estimated dietary intake (EDI) is exceeded. The results obtained from this study suggest that washing, drying, and remelting significantly removed contaminants from recycled PETE at varying magnitudes, depending upon type and residual concentrations of the contaminants adsorbed on and absorbed in polymer matrix. Most extraction data obtained suggest that migration of the residual contaminants from the extruded PETE sheets occurred in the food simulants at concentrations lower than 10 ppb. At very high concentrations of butyric acid and benzene, a higher rate of the contaminant migration from the extruded PETE into the food simulants was observed. This resulted in contaminant concentrations exceeding 10 ppb. The migration data obtained from these samples would represent the most conservative conditions.

PA-0008-10/95

Project Title: Effects of Radiation on Packaging Materials Used for Pre-packaged Foods

Project Leader: V. Komolprasert, NCFST/FDA,

Project Collaborators: C. Adhikari, NCFST/IIT, D. Thayer, ARS/USDA, K. Morehouse, FDA/CFSAN, and P. Hansen, FDA/CFSAN

In this study, FTIR, HPLC, GC/FID and GC/MS were evaluated as analytical methods for identifying and quantifying any radiolytic products which are formed in the soaker pad, PETE and PETG. An HPLC method was developed and used to quantify mono- and disaccharides which may be cleaved from the cellulose in the soaker pad after irradiation with 2.4 kGy dose of ?-irradiation at 10°C. The analytical results indicate that mono- and disaccharides migrate into a 10% aqueous ethanol food simulant at concentrations of 16-40 ppb and 63-143 ppb, respectively. Other polysaccharides were not detected (<10 ppb). There were no radiolytic products detected that migrated into the n-heptane solvent. The results from the headspace gas analysis indicated that there was no apparent effect of gamma irradiation at 2.4 and 10 kGy evolution of volatile hydrocarbons from PETE, PETG and the soaker pad.

PA-0009-10/95

Project Title: Guidelines for Automated Package Inspection

Project Leader: S. A. Morris, UIUC,

Project Collaborators: G. Sadler, NCFST/IIT, W.D. O=Brien, UIUC, A. Ozguler, UIUC, Y. Song, NCFST/FDA, and Melvin Pascall, NCFST/FDA.

New types of shelf-stable food packages have been developed that offer the processor lower energy, storage and packaging costs, and offer the consumer better nutrition, increased product quality and easier preparation. The major restraint on the implementation of these types of packages is the regulatory requirement for 200% manual visual inspection for seal defects during production. Human inspectors suffer from unpredictable performance variations. What is needed is an automatic, on-line, nondestructive evaluation technique. This study evaluated all available types of package testing methods, and found ultrasonic imaging be the best available choice of nondestructive methods. Scanning Laser Acoustic Microscopy (SLAM) is a successful method for the evaluation of defects, but need for access to both sides of the material, and the cost and complexity of the equipment make it of limited usefulness. We have developed a new method of signal processing (termed the Boundary Integral Amplitude (BAI) method) that makes the generation of a 3-D image of the material possible using a simple pulse-echo transducer. This method will image subwavelength sized defects, using backscattered acoustic energy, and provides a promising path for high speed sensor development. Future plans are to develop this into a demonstration-scale unit, using a phased-array transducer to determine the design parameters for successful high-speed on-line scanning.

PA-0010-10/95

Project Title: Organic Compound Migration in Plastics: Advanced Concepts

Project Leader: G. Sadler, NCFST/IIT, and S. Hussaini, NCFST/IIT

The FDA is concerned that recycled plastics may harbor contaminants acquired through storage abuses. There is concern that plastic containers may be used for interim storage of potentially hazardous materials. The purpose of this project was to develop a systematic assessment of the safety of recycled polymers for food contact based on migration data and mathematical models.

Diffusion, solubility and permeability data have been used to model surrogate uptake during the challenge phase of "Points to Consider" studies and desorption during processing phases for pilot level studies. Projections have been accurate to within 5%. Models have correctly predicted the outcome of APoints to Consider@ type studies for PET and polypropylene/ethyl vinyl alcohol composites. A method of calculating diffusion has been developed which provides insights into molecular processes of volatile sorption and migration, including dual sorption and solvation mechanisms. Models have suggested possible improvements in polymer processing to enhance removal of post consumer contaminants.

PA-0010-9/99

Project Title: Characteristic and Extent of Chemical Contaminants in Recycled Paperboard.

Project Leader: M. Pascal, NCFST/FDA, G. Sadler, NCFST/IIT

The objectives of this project were to develop a database of organic and inorganic contaminants found in selected samples of recycled paperboard and to compare levels and types of contaminants in recycled paperboard with those found in the virgin material using a quick method of analysis when compared to conventional methods. This project compares TE/GC-MS findings with those of published classical methods. Spiking and recovery studies with FDA surrogate classes were undertaken. Qualitative and quantitative analyses for the organic contaminant contents in samples of the paperboard by TE/GC-MS methodology were completed. Representatives from FDA in Washington and from the paperboard industry were consulted, and five surrogates were subsequently chosen. These surrogates were identified using the GC/MS at concentrations ranging from 15 ppm to 0.5 ppb in the recycled paperboard. The peaks of these compounds were matched to those in the computer library in order to identify the presence and concentrations of the organic contaminants in the paperboard being tested.

PA-0012-10/96

Project Title: Effect of Functional Barriers for Fatty and Moisture Packages with Recycled Pulp

Project Leader: Y. Song, NCFST/FDA, V. Komolprasert, NCFST/FDA

Project Collaborators: W.A. Hargraves, NCFST/FDA, T. Begley, FDA/CFSAN, G. Sadler, NCFST/IIT, M. Tolliver, McDonald=s-Perseco

The objective of this study was to test and develop analytical methods for quantifying surrogates in spiked papers. The 21 CFR 176.260 permits the use of pulp from reclaimed paper for food packaging applications as long as any poisonous or deleterious substances do not migrate into the food. Most commercially available paper packages for fatty and/or moisture foods, where high temperature is applied, have various coatings such as PE, PP, and PET on a virgin paper layer (eg., french fries and various TV dinners). The safety of recycled paperboard for food contact, therefore, should be assessed for its functional barrier, and the effectiveness of the functional barrier relative to its type and thickness should be determined. Four potential surrogate contaminants were selected, and analytical procedures for quantifying surrogates in recycled paperboard were developed. In the future, analytical methods for quantifying the surrogates in food simulating systems will be developed, and extraction experiments will be performed to measure the concentration of the residual contaminants migrating from the paperboard into the food simulating systems through the functional barrier during cooking.

PA-0014-10/97

Project Title: Effect of Functional Barriers for Fatty and High Moisture Food Packages with Recycled Pulp

Project Leader: Y. Song, NCFST/FDA and V. Komolprasert, NCFST/FDA

The objectives of this project were to develop an analytical method for quantifying the surrogates in paper at various spiking levels, and to develop analytical methods for quantifying the surrogates in the FDA-suggested aqueous and fatty food simulating solvents.

An analytical procedure for quantifying five surrogate contaminants in paper were successfully developed and verified at spiking concentrations of 1-50ppm. The recoveries of the polar surrogates benzophenone and PCP were in the ranges of 88-97% and 95-105% with relative standard deviations (RSDs) of 3%, respectively. The recoveries of the nonpolar surrogates anthracene, methyl stearate, and dimethyl phthalate were in the ranges of 92-100, 87-94, and 91-101% with RSDs of 3%, respectively. The results indicate that the procedure is effective and precise enough to extract and quantify the nonvolatile surrogates from the recycled paper, regardless of their polarity, and may be applicable to the determination of other contaminants in recycled paper/paperboard. Analytical procedures for quantifying the surrogates in the FDA-suggested aqueous and fatty food simulating solvents were also successfully developed and verified at concentration levels of 1-1000ppb. Recoveries of anthracene, methyl stearate, benzophenone, and PCP from 10% ethanol/water were in ranges of 71-95%, 80-93%, 81-106%, and 88-102% with RSDs of 2-4%, respectively. Recoveries of anthracene and benzophenone from 100% ethanol were in ranges of 81-94% and 82-95% with RSDs of 3%, respectively. Recoveries of methyl stearate and PCP from isopropanol were in ranges of 94-99% and 82-100% with RSDs of 3%, respectively. Extraction experiments are in progress to measure concentrations of the residual contaminants migrating from a spiked paperboard into the food simulating system through polypropylene film barrier with thickness of 1-2 mil at worst scenario conditions (100oC, 2 hours, 50ppm spiking level). The extraction data will be evaluated, based on 0.5 ppb threshold of regulation.

PA-0015-10/96

Project Title: Post-process Contamination of Flexible Pouches Challenged by In Situ Immersion Biotest

Project Leader: Y. Song, NCFST/FDA

Project Collaborators: W.A. Hargraves, NCFST/FDA, V.M. Subramanian, NCFST/IIT, J. Ulaszek, NCFST/IIT, P. Shah, NCFST/IIT

The objective of this study was to determine the effect of high-temperature retorting process on the physical characteristics of the microchannel, to evaluate the significance of various processing parameters on microchannel penetration, and to determine the critical microchannel diameter in flexible pouches through the biotest using a retort. Determining the critical microchannel size at which microbial contamination may occur is a prerequisite for establishing the lower limits of sensitivity required for nondestructive inspections of plastic package defects. A wide range of pinhole and microchannel leak sizes have been reported (10 to 33 µg) as the minimal diameters for microbial contamination. Experimental conditions have not been able to simulate the actual processing conditions experienced by food processors. A systematic approach to overcome these limitations is to use 'in situ' immersion biotesting on a pilot plant scale to evaluate the effect of risk parameters likely to be encountered by the packages through the retort cooling. This study was to establish the basic criteria for 100% nondestructive testing of flexible pouches to reduce the potential health risks. Given the conservative conditions described in this report for flexible retort pouches with 3 mm width seals and cooling water contamination levels of 106 CFU/ml, the selected microorganism can penetrate microchannels as small as 7 µm, but if the seal width is 6 mm and the cooling water is chlorinated and the contamination level is lowered to 103 CFU/ml, the minimum microchannel diameter for penetration can be as large as 41 µm.

No #-10/97

Project Title: Characteristic and Extent of Chemical Contaminants in Recycled Paper Board

ProjectCollaborators: M. Pascall, NCFST/FDA and G. Sadler, NCFST/IIT

The objective of this project was to develop a database of organic and inorganic contaminants found in selected samples of recycled paperboard. To compare levels and types of contaminants in recycled paperboard with those found in virgin material using a rapid method of analysis when compared to conventional methods.

Analysis of the paperboard using thermal desorption has shown the presence of several organic compounds in the virgin and recycled paperboard samples. These compounds were identified by comparison with standard compounds in the library of the mass spectrometer software. A second set of paperboard samples received from the FDA Washington has also been analyzed by GC/MS. These samples were five boxes with Post breakfast cereal labeling. The final list of surrogates selected were naphthalene, 4,4=-bis(diethylamino)benzophenone, 2,4-dichlorophenol, dimethyl phthalate and methyl stearate. The average recovery found for these compounds is 84%. Currently, data collected from duplicate GC/MS qualitative and quantitative analyses of the recycled and virgin paperboard samples are being analyzed.

The metal ions identified by voltammetry were cadmium, lead, copper and arsenic. Those identified by induction couple plasma are arsenic, cadmium, chromium, copper, lead, iron, tin, and zinc. A total of eight recycled and one virgin paperboard samples were analyzed for metal ions. These represent materials from five different recycled manufacturers. An abstract of the results (both organic and inorganic) from this project was submitted to IFT for presentation at the 1999 IFT conference scheduled for June 1999. Manuscripts for publication in a referred trade journal are being prepared. Duplicate analyses for lead, cadmium and copper will be performed as soon as the voltammetry equipment is repaired. All other analyses have been completed except mercury. It was decided that the analysis for mercury will be cancelled because additional equipment is needed to accurate results.

PA-0016-1/98

Project Title: Fundamental Chemical Changes in Food Packaging Materials by Gamma and E-beam Irradiation

Project Leader: V. Komolprasert, NCFST/FDA,

Project Collaborators: D.Thayer, ARS/USDA, T. Begley, FDA/CFSAN, T. McNeal, FDA/CFSAN

This project will continue under new funding and slightly modified objectives as PA-0021.

The objective of this project is to generate analytical data for assessing the difference or equivalence of gamma and electron beam on packaging materials used for irradiated prepackaged foods. The analytical data obtained also will be used to determine if there are any new compounds to be formed and what the concentrations these compounds, and the suitability of the test materials for irradiation at wide applicable doses. These results will help develop test protocol for assessing other packaging materials, and assist the Office of Premarket Approval in developing guidelines or a points-to-consider document for industry to follow.

A soaker pad and two amorphous and nonoriented semi-rigid PET copolymers with cyclohexanedimethanol (CHDM) were studied. The initial results are as follows:

Soaker Pad: The results obtained from the HS/GC/MSD analysis at 90oC showed that the 7-kGy gamma irradiation generated 2.3-3.14 ppm di-tert-butyl benzene, 0.78-1.40 ppm nonanal, and 0.24-0.41 ppm cyclopentanone. Irradiation significantly increased percent soluble solids extracted from the soaker pad specimens. After irradiation the soluble solid in the 10% aqueous ethanol solution was 0.43 % compared to 0.28% before irradiation. The percent solid extracted from soaker pad specimens using 2-propanol increased with storage time, ranging from 0.71 to 0.94 % in unirradiated and from 0.82 to 0.98 % in irradiated. Glucose and cellobiose that could be generated from cellulose were present in the soluble solid extracted from unirradiated and irradiated soaker pad specimens with 10% ethanol solution at concentrations lower than 10 ppb based on soaker pad weight. The complete analysis of the soluble solid is underway.

Amorphous and nonoriented semi-rigid PET: The PET materials have been irradiated with electron-beam accelerator at ambient temperature at 5, 25 and 50 kGy. The volatiles are being analyzed using HS/GC/FID and HS/GC/MSD. Nonvolatiles have been extracted using 10% ethanol and n-heptane food simulating solvents. Irradiation did not increase the percent soluble solid. Regardless of irradiation, soluble solid extracted from the PET using both food simulants is lower than 0.02% based on the PET weight. Analysis of the soluble solid by HPLC is underway.

PA-0018-10/98

Project Title: Organic Compound Migration in Plastics: Molecular Principles

Project Leader: G. Sadler, NCFST/IIT

The objective of this study was to anticipate the behavior of organic compounds in plastic packaging materials based solely on the chemical properties of polymer and penetrant. Mathematical models exist for predicting the migration rate of compounds in polymers so long as diffusion and solubility of the migrating compounds in the polymer are known. Many of these equations have existed and had their validity confirmed by over 100 years of use. However, the application of these models have been limited by the difficulty of quantifying diffusion and solubility values in polymers. This difficulty has resulted in literature data which are highly varied and unreliable. Over the past several years the NCFST has been compiling migration data on organic compounds in plastics. This database appears to be the largest every compiled using a single test method. The data has led to mathematical predictions of migration which have been the basis of millions of dollars worth of decisions concerning plant design and process control for recycled polymers. They have provided a basis for understanding which polymers are recyclable back into food contact polymers and have led to predictions on how likely it is for radiolytic products to migrate from irradiated packages into foods. The data has also provided a basis for determining whether a polymer is a functional (ie effective) barrier in multilaminate structures.

PA-0018-10/99

Title: Effect of ozonation sterilization on food packaging materials

Project Leader: Yoonsook Song

Objective: To measure migration of residual compounds and degradation products from PET and HDPE polymer bottles into ozonated water

PA-0018-10/99

Title: Effect of Ozonation Sterilization on Plastic Packaging Materials

Project Leader: Yoonsook Song

Project Collaborators: G. Sadler, NCFST/IIT, L. Xu, Praxair, J. Yuan, Air Liquide, F. Al-Taher, NCFST/IIT

Objective: There has been some anecdotal evidence that ozonated bottled water has more off-flavor than does non-ozonated bottled water. The ozone may also facilitate the migration of residual compounds and degradation products from the polymer bottles. The objective of this project was to measure migration of residual compounds and degradation products from PET and HDPE polymer bottles into ozonated water. A purge and trap procedure was developed to extract volatile compounds from non-ozonated and ozonated water in contact with PET, HDPE, PP or EVA polymers. Volatile extracts were identified and quantified using a GC-MS coupled with an automated thermal desorber. Several characteristic aldehydes and ketones were found, which may cause off-taste in ozonated water with a low organoleptic threshold. Extraction data indicated that migration occurred in ozonated water at concentrations lower than the FDA's 0.5 ppb limit.

PA-0020-10/98

Project Title: Cataloging-Organic Compound Cataloging-Organic Compound M

Project Collaborators: G. Mazo, NCFST/IIT.

Project Leader: G. Sadler, NCFST/IIT

The objectives of this project were to: 1.Determine data (diffusion, solubility, permeation) necessary to model up-take of various classes of compounds by principal packaging polymers; 2. Develop and execute models for organic compound penetration into packaging polymers with an emphasis on PET; 3. Validate model predictions through pilot scale recycling studies; 4. Seek to understand the underlying principals of migration with an objective of establishing a priori estimates of polymer/penetrant behavior from chemical/physical properties of the two components of the system; 5.Use data and models to anticipate and improve levels of contaminant removal during polymer recycling; 6.Use pilot plant capabilities to aid in commercial validation of recycled polymers using FDA "Points to Consider" protocols and NCFST established diffusion data; and, 7. Expand the use of migration data and models beyond the realm of safety and explore ameliorative and detrimental quality phenomena in food/package systems. A library of mass transfer equations suitable for studying migration in polymers has been compiled. Data and models have been used to project the behavior of organic compounds during recycling and following treatment with ionizing radiation.

PA-0020-10/99

Project Title: Effect of Functional Barriers for Fatty and High Moisture Food Packages with Recycled Paperboard

Project Leader: Y. Song, NCFST/FDA, V. Komolprasert, NCFST/FDA

Project Collaborators: W. Hargraves, NCFST/FDA, T. Begley, NCFST/FDA

In a response to an increasing demand by industry, the FDA is considering developing a surrogate testing protocol for recycled paper/paperboard similar to that for recycled plastic. This study will help the FDA determine if the suggested model surrogate con taminants are suitable to test the efficacy of industrial recycling processes in removing the contaminants to levels of no concern. This work will also deter mine the minimal thickness of a functional barrier that will effectively restrict migration without exceeding the threshold of regulation. Extraction experiments were completed. Concentrations of the residual con taminants migrating from paperboard into the food simulating system through the functional barriers during the cooking conditions were measured, and the extraction data were evaluated based on 0.5 ppb threshold of regulation. Development of a method to closely laminate the paper with polypropylene film such that no delamination will occur during the extraction at elevated temperatures was a limiting factor. The conclusion is that PP is not a good barrier to block the migration of contaminants expected to be in post-consumer paper/paperboard to a level of no concern.

PA-0021-10/99

Project Title: Fundamental Chemical Changes in Food Packaging Materials by Gamma and E-beam Irradiation

Project Leader: V. Komolprasert, NCFST/FDA

Project Collaborators: D. Thayer, ARS/USDA; T. Begley, FDA/CFSAN; T. McNeal, FDA/CFSAN

Objective: The objective of this project is to generate analytical data for assessing the difference or equivalence of gamma and electron beam on packaging materials used for irradiated prepackaged foods. Ionizing irradiation from gamma rays and e-beams for sterilized medical products has been widely used for many decades, but irradiation for food just recently received an increased interest after red meat irradiation was approved by the FDA (FDA, 1997). However, the number of FDA-approved food packaging materials for irradiation is limited. Selection of packaging materials for use in food irradiation depends on the resistance or stability of the material to chemical changes when irradiated at commercial doses. The chemical compounds initially present or radiolytic products formed upon irradiation that could or might migrate into food at storage conditions are a safety concern. As a result, a premarket safety evaluation by the FDA for the material is required. This study proposes a systematic approach using fundamental kinetics to determine the production of any radiolytic compounds based on chemical structures of polymers to be irradiated by gamma rays and e-beams at different irradiation doses and post-irradiation storage conditions. This study will identify and quantify volatiles and non-volatiles formed upon exposure to gamma rays and e-beams at different irradiation conditions. The data will be analyzed to assess the effects of gamma and e-beam radiation on chemical changes in the selected test food packaging materials and their suitability for food irradiation.

PA-0022-10/00

Project Title: Evaluation of Non-Destructive, On-Line Leak Detection and Seal Strength Determination Systems for LACF Packaging

Project Leader: M. Pascall, NCFST/FDA

Project Collaborators: C. Sizer, NCFST/IIT, J. Gratzek, Tetra Pak, D. Park, FMC, C. Hakl, Dean Foods, K. Ghiron, Magtherm, J. Johannessan, FDA/MOD1, J. Richtsmeier, Sonoscan

Objective: Many shelf stable food processors often store products for a week or more before shipment to ensure the detection of spoiled and contaminated packages by visual and statistical means. An automated system that can non-destructively perform testing of all packages produced is a major advantage. The objectives of this research are to evaluate pressure differential for leak detection in semi-rigid packaging, evaluate magnetic resonance (MR) as a non-destructive method for bacterial contamination detection in packaged low acid canned foods, and evaluate ultrasonic imaging for non-destructive seal strength determination in polymeric trays. It was found that pressure differential was more sensitive to pinhole detection that to channel leaks. Pressure differential is capable of detecting channel leaks ³ 40mm and pinholes ³10 mm in diameter. It was also found that pressure differential is unsuitable for leak detection in packages with no headspace volume. The evaluation of MR for leak detection and bacterial contamination identification was completed. MR identified B. stearothermophilus and B. subtilis in soymilk and texture changes in cheese sauce. The investigation of the sensitivity of ultrasonic imaging for the evaluation of seal strength was also completed. This study correlated the sealing conditions and peel strength of the test trays with ultrasonic imaging.