Science Platforms > RSAFETYA

Completed Projects Food Safety/HACCP

SA-0003-3/92

Project Leader: J. Larkin, NCFST/FDA,

Project Collaborators: B. Anderson, Dean Foods Co., V.M. Balasubramaniam , NCFST/IIT, S. Chandru, NCFST/IIT, S. Rambo, Dean Foods, J. Rynberg, Gerber Products, B. Wilson, Anderson Instruments, G. A. Clark, Taylor Env. Inst.

Project Title: Development of a Testing Protocol for Electronic Sensors Used as Temperature References

The objective of this project was to develop test protocols which could be conducted on an electronic temperature sensing device to determine its ability to be used as a reference temperature measuring device in the thermal processing of low-acid foods. The mercury-in-glass thermometer (MIG) is currently the temperature reference for commercially sterilized low-acid canned foods (LACF). Since the adoption of the MIG as the reference temperature device for LACF processes a number of devices have been developed that appear to be as durable and as accurate. These devices have not been examined to the point where it can be determined if they are acceptable as alternate temperature measuring devices (ATMD) for LACF processes. In the first year of this project an ATMD was installed on three commercial retorts and the pilot plant unit at the NCFST, and a survey of current practices and uses of, the MIG in low-acid canned food processing facilities was initiated. During the second and third year, the ATMD was tested, both in the pilot plant and in commercial settings, and a draft testing protocol for the drift test was developed from the data collected. To test the drift test protocol a second ATMD was installed at two commercial settings. Environmental and electromagnetic interference (EMI) tests were conducted on both devices. A draft protocol for drift, EMI, and environmental testing were completed. Environmental testing of the ATMDs indicated that they should function as intended in a harsh environment such as in a LACF facility.

SA-0004-4/92

Project Leader: G. Fleischman, NCFST/FDA

Project Title: Determinants of Cold Spot Temperature in Microwave Heating

The objective of this project was to predict temperature distribution in microwave heated foods and to investigate the factors which affect temperature distribution in foods. The nonuniform rate of energy deposition in microwave heating is a serious problem for a variety of microwave heating processes. In reheating, food quality is compromised and safety is a potential problem. In sterilization, safety is the issue. The purpose of this project is to develop new approaches for the analysis of microwave heating. These approaches will provide means of assessing the safety of a microwave process through examination of the variables which influence energy distribution in microwave heated foods. This past year's work has uncovered a non-numerical solution to the heat equation with a Maxwell energy distribution for any power level or heating duration. Previously, a solution was obtained only for long term/low power heating in slabs. The prediction of a stable temperature profile was borne out with experiments. The same prediction for cylinders was shown to be true.

SA-0005-10/93

Project Collaborators: G. Skinner, NCFST/FDA, M. Cirigliano, T. J. Lipton

Project Title: NCFST Steering Committee for the Development of a Library of Generic HACCP Plans for the Food Industry

The objective of this project was to organize a committee of HACCP experts from industry, academia, and government and operate in a workshop format to develop a library of generic HACCP plans and models. These models would serve as resources to provide technical direction to companies who are interested in implementing HACCP-based food safety programs. The project utilized a proactive experimental approach to provide a platform for the active participation of food industry experts, experienced in the use and management of HACCP. Eight meetings of the HACCP Library Steering Committee were held since July 12, 1993 with representatives present from academia, industry and governmental agencies. A finalized project protocol, a mission statement, a disclaimer, steering committee and product/process working group definitions were approved by the steering committee. A format for what would be included with the generic HACCP plans requested was approved. The first and second priority food categories were selected for the collection and review of generic plans. These categories were seafood and meat and poultry products, respectively.

SA-0006-10/93

Project Leader: G. Skinner, NCFST/FDA, H. Solomon, CFSAN/FDA, G. Fingerhut, NCFST/IIT

Project Title: Evaluation of Biocontrol as a Barrier Against Microbial Toxicity

The objective of this project was to evaluate the use of biocontrol or biological competition to serve as a secondary barrier against toxin production by Clostridium botulinum in extended shelf life refrigerated foods possessing a pH greater than 4.6. Processors are seeking additional barriers to incorporate into extended shelf life refrigerated foods to increase their safety in case of exposure to temperature abuse. Lactic acid producing microorganisms have the potential for serving as an additional protective barrier in foods that currently utilize refrigeration as their only protection against microbial growth and/or toxin production. The experiments indicated that if an appropriate lactic acid producing bacteria was found for a specific food system application using appropriate experimental methods, that the microorganism may be able to serve as a secondary barrier in extended shelf life refrigerated foods against C. botulinum formation under conditions of temperature abuse.

SA-0008-10/95

Project Leader: N.R. Reddy, NCFST/FDA,

Project Collaborators: V.M. Balasubramaniam, NCFST/IIT, H.M. Solomon, CFSAN/FDA, E.J. Rhodehamel, Cryovac, Sealed Air Corp., F.X. Zimmerman, ABB Autoclave Systems, Inc.

Project Title: Inactivation of Clostridium Botulinum Spores by High Pressure Processing (HPP)

The objectives of this project are to inactivate spores of C. botulinum type A and nonproteolytic type B strains in a model food system, to determine D- and Zp- values of spores of C. botulinum type E strains in a model phosphate buffer system during HPP, and to evaluate the effect of pressure (up to 827 MPa) and temperature (up to 120°C) on inactivation of spores of C. botulinum types A and B in a model buffer system as well as a low-acid food product. Recently, use of HPP as a food processing method became a subject of renewed interest because it can be used to inactivate microorganisms in certain foods or food ingredients without a decrease in product quality. There are no published reports on the resistance of C. botulinum spores to HPP. Biological validation of a HPP process can be very time consuming. There is a need for a kinetic based process delivery calculation procedure. Process establishment would then be a function of process conditions and the resistance of the appropriate organism of concern. Previously we studied the effect of pressure. temperature, and time on inactivation of

C. botulinum types A and E and nonproteolytic type B spores in phosphate buffer (pH 7.0).

Results of this study will benefit the FDA, industry, and NCFST in the application of HPP for inactivation of C. botulinum spores in various low-acid foods and food ingredients potential

increase in the production of safe extended shelf stable foods with improved product quality, appearance, and nutritive value. This research will compliment existing C-FAR competitive grants project on AHigh Isostatic Pressure inactivation of Selected Food Spoilage Microorganisms@.

SA-0009-10/96

Project Leader: J. W. Larkin, NCFST/FDA, and S. H. Spinak, CFSAN/FDA

Project Title: Electronic LACF Process Filing Criteria

The objectives of this project were to develop a set of criteria to be used when developing and validating a computerized Low-Acid Canned Food (LACF) filing form generator, for submission electronically or in printed format.

The Food and Drug Administration (FDA) issued a final rule (CFR Title 21 part 11) concerning electronic records, that went into effect in August, 1997. This rule allows any Title 21 required signature (i.e, low-acid canned foods (LACF) filing forms) to be made using an electronic procedure. Part 11 also notes that for the FDA to receive documents with electronic signatures there needs to be a phase-in period. This project was intended to minimize this phase-in period for LACF filings. A computerized filing procedure will eliminate transcription errors by the FDA, improve the ability to determine if the FDA has received a filing, improve ease of filing, increase the speed of processing a filing, and improve the accuracy of a filing. A report describing the data file format and Asmart@ checking rules for all forms (2541, 2541a, and 2541c) were completed. These rules can now be incorporated into computerized form filling programs. The long time to develop the Asmart@ checking rules, the inability to identify an individual to work on the development of a draft electronic filing system, and the decision that an electronic filing system should be completed by the FDA forced the project to eliminate any work on the development of an electronic filing system. Any future work on an electronic LACF filing system will be conducted by the FDA. The recent (Sept. 1998) passage of the Paperwork Elimination Act, has added an urgency to this technology. The Paperwork Elimination Act requires Federal Agency=s to have by the end of 2003 a procedure whereby any required paperwork can be filed with the government electronically.

SA-0010-10/96

Project Leader: G. Skinner, NCFST/FDA

Project Title: Stability of Clostridium botulinum Toxin in Sample Extracts Under Freezing and Refrigeration Conditions

The objectives of this research were to evaluate the effect of freezing, refrigeration and freeze/thaw cycling on the stability and activity of C. botulinum toxin in sample extracts from media and model food systems.

Studies performed to evaluate food safety from C. botulinum involve the inoculation of spores into the test matrix, then storing the samples under controlled temperatures. Portions of the food are removed at designated times and analyzed for the presence and/or quantity of toxin. Scientists question the effect of storage variables such as temperature and time on the activity of C. botulinum toxin.

This study shows good toxin stability for extracts prepared from sterile cultures containing only type A, E and nonproteolytic type B C. botulinum. Extracts prepared from inoculated sterile culture media as in this study may be stored for long periods of time under refrigeration or freezing with no loss in toxin activity. The study also showed that these extracts may be frozen and thawed up to 3 times with no loss in toxin formation. It is important to note that the results of this study are specific for toxin extracts prepared from sterile media inoculated with only C. botulinum spores.

SA-0012-10/96

Project Leader: G. Skinner, NCFST/FDA, and J. Larkin, NCFST/FDA

Project Collaborators: F. Grabiner, LifeLines Technologies, Inc. and M. Losikoff, FDA Division of Seafood

Project Title: Evaluation of a Consumer Type Time/Temperature Indicator for Estimation of Time to Toxin Formation by Clostridium botulinum as a Function of Storage Temperature.

The objective of this research project was to evaluate whether a consumer type Time/ Temperature Indicator can be manufactured to react to a specified set of time/temperature criteria and therefore be useful in predicting when a food product has been stored under potentially hazardous conditions. Because of the safety questions associated with Modified Atmosphere Packaged (MAP) fish and vegetables and extended shelf life refrigerated foods, additional safety measures are being sought to protect consumers from potential hazards associated with these food products. Utilization of consumer type Time/Temperature Indicators (TFls) represents a means of indicating storage conditions which may render a particular food hazardous, and alerting the consumer of this potential hazard. TTIs may be manufactured to a custom set of time/temperature conditions which have been found to either represent a potential health hazard or result in poor quality. For instance, research has shown that it is possible in some cases for spores of C. botulinum to germinate, grow and produce toxin in extended shelf-life refrigerated foods exposed to elevated temperatures. It may be desirable to attach a consumer type TTI which is designed to respond to a predetermined set of time/temperature criteria to such foods. TTIs designed to operate reliably and accurately appear to have great potential for minimizing possible public health risks associated with certain types of foods, particularly refrigerated foods. The conservative curve and its corresponding mathematical equation representing most rapidly achievable C. botulinum toxin formation as a function of incubation temperature was agreed upon and a consumer type TTI was manufactured to emulate equation behavior.

SA-0013-10/96

Project Leader: G. Fleischman, NCFST/FDA

Project Title: Safety Considerations in Microwave Reheating

The purpose of this study was to predict temperature range in microwave-heated foods, specifically of homogeneous food slabs. To ensure safe heating or reheating of food from a microbiological point-of-view, the minimum temperature achieved within the food should be known. In microwave heating, the location of the point of minimum temperature is difficult to determine due to the complex heating patterns established within the food. Only by coincidence would a few random temperature measurements within the food hit the point of minimum temperature. To deal with this difficulty, it is beneficial to predict the temperature range within the food. Random sampling of temperature within the food gives an estimate of the maximum temperature. Subtracting the temperature range from the maximum temperature gives a conservative estimate of the lowest temperature. Work under this project succeeded in solving the heat equation, including an energy distribution obtained from the full set of Maxwell equations, for homogeneous foods, under the assumption of slab geometry and temperature-independent thermal and dielectric properties. The solution is a prediction of temperatures as a function of time for any power level of microwave energy. Although the solution is useable in standard spreadsheet software such as Microsoft Excel, further simplifications were accomplished. A modification of this solution was also obtained for the purpose of experimental validation of the model. The project officially ended September 30, 1997 and was not renewed.

SA-0015-4/98

Project Leader: G. Fleischman, NCFST/FDA, an W. Kinell, CPC Food Service

Project Title: An On-line Database of Thermal Kinetic Parameters for Microbial Destruction in Foods

The objective of this project was to assemble collective literature data on the thermal death time kinetic parameters of pathogenic organisms in a variety of food environments and place these data on the World Wide Web for on-line access, and to determine feasibility of continued upkeep of the database. A preliminary web page (now removed) was constructed. It consisted of a table of kinetic parameters for the thermal death time of C.botulinum collected from a preliminary search of the literature. However, it was determined that this project practically duplicated information currently available in a printed single source (ICMSF, 1996) for thermal death time kinetics that was previously unknown to the Principal Investigators. Furthermore, it was determined that further upkeep of the database in a form that would make it truly useful to investigators could not be justified based on the resources at hand. Therefore the project was terminated.

SA-0016-10/97

Project Leader: V.M. Balasubramaniam, NCFST/IIT, G. Fleischman, NCST/FDA, N. Reddy, NCFST/FDA

Project Collaborators: P. Dunne, Natick Labs, K. Ghiron, IIT, S. Lloyd, PurePulse Technologies, C. McDonald, Purepulse Technologies, S. Ravishankar, NCFST/IIT

Project Title: Safety Assessment of Pulsed Electric Field (PEF) Processing Technology

The objective of this project is to develop methods for the prediction of microbial lethality during PEF processing. At present there are no means of predicting microbial lethality in a PEF process. The fact that different implementations of PEF technology result in different lethality to the same microorganism indicates a lack of sufficient understanding of the basic effect of PEF on microorganisms--an understanding that is vital if PEF is to be commercialized.

The project has progressed according to plans. After receiving the pulsing unit, it was modified to allow precise control over pulse duration and time between pulses. A static chamber was designed and submitted for fabrication as a prototype. It was adequate. A gel was found and used in several preliminary treatments with E. coli O157:H7 and Listeria monocytogenes. These experimental runs gave a consistent 3 log reduction for 10 pulses at constant temperature for E. coli O157:H7 and a one log reduction for Listeria monocytogenes. The nonuniform field tests were not undertaken. Limitations with the pulsing unit did not allow a large enough sample volume to allow testing for field uniformity.

SA-0017-10/97

Project Leader: G. Skinner, NCFST/FDA, H. Solomon, CFSAN/FDA, G. Fingerhut, NCFST/IIT

Project Title: Differentiation Between Types and Strains of Clostridium Botulinum by Riboprinting

The objectives of this project were to determine if the DuPont Riboprint system can effectively differentiate between types and individual stains of C. botulinum and therefore serve as a tool to help reduce the incidence of foodborne illness.

The Qualicon RiboprinterJ Microbial Characterization System, currently used to provide genetic Afingerprints@ or Riboprint patterns of microbiological isolates, was evaluated for its ability to differentiate between major types and individual strains of Clostridium botulinum. Pure spores of C. botulinum type A, proteolytic type B, nonproteolyt-ic type B, type E were inoculated onto modified anaerobic egg yolk agar and incubated 24 hrs at 35oC. Plates were rinsed with buffer (2mM Tris + 20mM EDTA) to remove cells which were heated for 10 minutes at 80oC, treated with lysing agent, then ribotyped using the Qualic-on Riboprint-erJ utilizing the enzyme EcoRI.

Riboprint patterns obtained for 30 strains of the 4 major types of C. botulinum most commonly involved in human foodborne botulism showed good differentiation within the genus. Proteolytic strains yielded the best and most consistent results. Pattern comparisons determined that 16 separate RiboprintJ groups exist amongst the 30 strains and that distinct and multiple banding patterns appear to exist within each major C. botulinum type. This degree of differentiation between strains of C. botulinum will allow this technique to be used in improving the safety of our food supply, in hazard analysis and identification, HACCP monitoring and validation, environmental monitoring, outbreak epidemiology and in inoculation studies. Establishment of a library of C. botulinum data, or genetic banding patterns specific for each strain of C. botulinum will provide crucial epidemiological information in the case of an outbreak of botulism by identifying specific strains and possible identification of the causative agent.

SA-0019-10/98

Project Leader: J. Larkin, NCFST/FDA

Project Collaborators: D. Park, FMC, S.H. Spinak, FDA

Project Title: System Validation Protocol for Computerized Sterilization Control

The objective of this study is to develop a validation guideline for computerized sterilization control systems. There is widespread use of computer control including PLC and PC based electronic control of in-container, in-flow low acid canned food (LACF) and refrigerated (chilled) food products. Unfortunately, there appears to have been one documented software failure attributed to the use of these systems which created an unintentional. but potential threat to public health. A product recall resulted. Inadequate system validation by the supplier was determined to be the cause. The LACF Good Manufacturing Practice (CFR Title 21, Parts 108,

113, and 114) regulations, while longstanding since the early 1970's, are silent in areas related to electronic process control systems. They do, however, contain sections which pertain to these control systems (21 CFR 108.35(a) and 21CFR 113.40(j) ). New systems must " . . . be operated or administered in a manner adequate to ensure that commercial sterility is achieved." Regulatory requirements including those addressed in LACF GMP'S, Seafood HACCP and the Proposed Infant Formula GMP's strongly imply or specifically state the mandatory need for the processor to have a written system validation plan where electronic process control is employed. An NCFST developed Guideline would serve the equipment supplier, food processor, and the FDA

Investigator as a critical guide to the life cycle development and implementation of computer control systems (software and related hardware) for commercial use with pasteurized or sterilized foods. This project is in the first of two phases. Phase I involves the assembly of critical documents already available within FDA and the industry on system validation protocols and existing requirements. Phase II consists of, with a collective perspective, developing a suitable guideline covering validation protocol, change control, security, re-validation, HACCP verification and prerequisite programs.

SA-0020-10/99

Project Leaders: V.M. Balasubramaniam, NCFST/IIT, and P. Slade, NCFST/IIT

Project Title: HACCP Plan Development for Fruit/Vegetable Juices Processed by Continuous High Pressure Processor Equipped with Aseptic Packaging System

The objectives of this study are to 1) identify product parameters likely to impact safety (e.g., pH. Brix, solids, initial microbial load, etc.) and to standardize conditions for production of citrus or berry juice using a continuous high pressure processor, 2) to develop a HACCP plan for juice processed using a continuous high pressure processor equipped with an aseptic filling system, 3) to validate the HACCP plan by challenging the high pressure processor with pathogenic microorganisms identified as potential hazards by the plan [e.g., Bacillus cereus (spores and vegetative cells), Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., Cryptosporidium parvum oocysts], and 4) to design a verification schedule for the HACCP system, and to verify the system at the designated frequency. There is a growing consumer demand for high-quality, "fresh-like@, minimally processed foods. High pressure inactivates microorganisms and enzymes, but does not adversely key quality attributes. This can result in the retention of color, flavor and nutrients. To date, no model HACCP system has been developed for fruit or vegetable juices processed using high pressure. The proposed project aims to develop a HACCP plan for juice processed using a Flow International continuous high pressure system. The HACCP plan will be validated through commission of high pressure processing system, and the HACCP system will be verified at a designated frequency to assure conformance to the plan, and production of safe juice products.

SA-0021-10/99

Project Title: Quantification of effects of processing on foodborne pathogens for minimally processed foods

Project Leader: G. Skinner, NCFST/FDA

Project Collaborators: Richard C. Whiting, FDA; Michael C. Cirigliano, Unilever; James T. Yuan, Air Liquide; T. C. Boersma, NCFST/IIT

The objective of this project was to obtain quantitative data on the risk associated with E. coli O157:H7 and its behavior during the steps involved in the production of minimally processed produce. The growth responses of a dihydrostreptomycin resistant strain of E. coli O157:H7 inoculated onto pieces and exudate of carrots, lettuce (iceberg and Romaine), cabbage, raddish, broccoli and cauliflower were studied at 25, 15, and 5°C. The effect of temperature on the growth of the bacterium on the different produce items was analyzed by the square root model, but a non-linear response was observed. The data obtained in this study was compared to the response predicted by the USDA's Pathogen Modeling Program. At 25°C, the predicted responses were higher than the observed, while at the lower temperatures, there was much closer agreement between the observed and predicted. The data generated will allow quantification of the response of E. coli O157:H7 in different, fresh, minimally processed produce items and could lead to various control interventions at different steps during processing and reduce the risk associated with these items.

SA-0021-10/99

Project Title: Quantification of effects of processing on foodborne pathogens for minimally processed foods

Project Leader: G. Skinner, NCFST/FDA

Project Collaborators: Richard C. Whiting, FDA; Michael C. Cirigliano, Unilever; James T. Yuan, Air Liquide; T. C. Boersma, NCFST/IIT

The objective of this project was to obtain quantitative data on the risk associated with E. coli O157:H7 and its behavior during the steps involved in the production of minimally processed produce. The growth responses of a dihydrostreptomycin resistant strain of E. coli O157:H7 inoculated onto pieces and exudate of carrots, lettuce (iceberg and Romaine), cabbage, raddish, broccoli and cauliflower were studied at 25, 15, and 5°C. The effect of temperature on the growth of the bacterium on the different produce items was analyzed by the square root model, but a non-linear response was observed. The data obtained in this study was compared to the response predicted by the USDA's Pathogen Modeling Program. At 25°C, the predicted responses were higher than the observed, while at the lower temperatures, there was much closer agreement between the observed and predicted. The data generated will allow quantification of the response of E. coli O157:H7 in different, fresh, minimally processed produce items and could lead to various control interventions at different steps during processing and reduce the risk associated with these items.

SA-0022

Project Title: Inactivation of Clostridium botulinum spores by high hydrostatic pressure

Project Leader: N. R. Reddy; NCFST/FDA; V.M. Balasubramaniam, NCFST/IIT

Project Collaborators: J. Dunn, NCFST/IIT; Robert Tetzloff, NCFST/IIT; E. J. Rhodehamle, Cyrovac; Edmund Y. Ting, Avure Technologies

The purpose of this project was to evaluate the effect of pressure (up to 827 Mpa) and temperature (up to 120°C) on the inactivation of spores of Clostridium botulinum type A and non-proteolytic type B in phosphate buffer and in a low acid food product. Little progress was made because of the new CDC Select agent laboratory registration procedures. Some results were obtained. At 620 Mpa, the levels of spores of strains 62A and 17B were reduced as the temperature was increased from 80 to 120°C. For spores of 17B, a 5 log reduction was observed at 620 Mpa at temperatures of 95 and 100°C.

SA-0024

Project Title: Thermal and non-thermal in-sell pasteruization

Project Leader: G. Fleischman, NCFST/FDA

Project Collaborators: G. Eves Ferrite Corp.; S. Palumbo, NCFST

The goals of this project are to mathematically and microbiologically determine the potential for the use of microwave energy to eliminate Salmonella Enteritidis (SE) in in-shell eggs and to determine if sub-megahertz ultrasound can be used as a non-thermal means of eliminating SE from in-shell eggs. Using a specially developed technique, it was observed that SE infection occurs in the albumen of the egg. Mathematical analysis showed that because of the differences in the dielectric properties between the yolk and albumen, the albumen is better heated than the yolk. Thus, it appears that in-shell eggs may be ideally suited for microwave pasteurization.

SA-0025-10/01

Project Title: Using magnetic thermometry to measure the effect of particle thermal and physical properties on the heating rate of aseptically processed food particulates

Project Collaborators: J. Larkin, NCFST/FDA; J. Dunn, NCFST/IIT

The objectives of this project are to evaluate magnetic thermometry as a tool for understanding how particle characteristics affect the in-flow thermal processing of low-acid particulate foods, and to relate the understanding of particle thermal processing parameters gained through magnetic thermometry to mathematical modeling of continuous aseptic processing of particulate foodstuffs. The MagTherm process offers significant flexibility in construction of the test particles. Current particles are cast using epoxy-glass microsphere mixtures. The thermal profiles of ½-inch cubes with different thermal conduction properties and particle densities will be measured. The results and understanding from these experiments will be applied to the development and validation of mathematical models of continuous aseptic processing of particulate foodstuffs.