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The Food Safety Consortium
Research Highlights 2005-06
University of Arkansas

Michael Johnson, University of Arkansas

Michael Johnson

Introduction

The research program for the FSC October 2006 meeting in Fayetteville was greatly enhanced, expanded and broadened.  Several outside speakers with expertise in pathogen control and detection at the pre and post-harvest stages presented. A hardbound proceeding to be published by the U of A Press is planned.  The new Buddy Wray Chair and Director of the Center for Food Safety and research coordinator for the Arkansas Section of the FSC, Dr. Steve Ricke, joined the faculty in mid-December 2005. He has hit the ground running and is working  closely with his peers at Iowa State and Kansas State to focus our collaborative efforts. He is also working closely with rest of the team members in Arkansas in developing new thrusts to help keep Arkansas competitive in food safety research and outreach programs.  Welcome, Dr. Ricke.   

Summarized below are some of the brief updates on research projects directed toward enhancing and improving the safety of poultry products from “farm to fork.” These are excerpts from PI reports based on their pre- and post-harvest research projects funded by multi-year grants, beginning in the 2005-06 funding cycle.

Pre-Harvest

Turkey poults age 4-12 days (Expt I) and turkeys at 7 (Expt II) or 13 weeks (Expt III) of age were treated with cold stress (I), or immune lowering drug, dexamethasone (II, III), and challenged with Listeria monocytogenes, E. coli  or both in a coarse spray (I) or in the drinking water (II) or in the feed and drinking water (III) and assayed for incidence of L. monocytogenes in hip and knee joint fluid or in liver tissue samples. At day 12, 5 of 8 birds were L. monocytogenes positive in the joint or liver tissue. For the 7-week-old Dex treated birds, by 7 weeks + 5 days, 5/13 were L. monocytogenes positive but by 7 weeks + 12 days none of the birds were positive. In Expt III, birds treated with Dex at 13 weeks by week 15 showed 5/7 = 71% positive for L.monocytogenes as compared to positive rates of 3/9 = 33% for unstressed controls and 3/13 = 23% for transport stressed birds. Thus, these results indicate this pathogen can infect other parts of turkeys besides the meat directly, namely their joints, and thereby serve as a previously overlooked source of pathogen contamination in poultry processing plant environments. 

Although FDA approval for poultry uses of antibiotics related to ciprofloxacin were supposedly rescinded in 2005 and its use decreased and discontinued, some ciprofloxacin resistant isolates of Campylobacter continued to be recovered in retail market samples of raw poultry in 2005. Using a direct plating method permitting enumeration, not just presence/absence determinations,  it was found that 96 and 43% of carcasses sampled contained countable numbers of total Campylobacter genus and of ciprofloxacin resistant Campylobacter respectively.  This incidence is of concern since this antibiotic is often prescribed for human bacterial infections.

The abilities of other normal bacteria present on poultry to promote formation of sticky biofilms with the pathogen C. jejuni were evaluated in  a model 96 well microtiter plate system with 11 different bacteria under both static and flowing fluid conditions.  The flowing conditions led to more C. jejuni biofilm formation and visible biofilms were most obvious with cultures of Streptococcus liquefaciens, Pseudomonas aeroginosa, Ps fluorescens and Citrobacter freundii. It is possible that formation of such biofilms protects this pathogen from chemical destruction, helping it to persist on poultry.      

Compared to control, non-starved cells, L. monocytogenes cells starved for up to 180 days in phosphate buffered saline were still invasive to target gut cells Caco-2 in model system tests. Starved cell survivors produced holes (plaques) in host cell lawns that were somewhat less numerous and smaller in diameter but nevertheless remained quite virulent as compared to the unstarved control cells of this pathogen.

These results reinforce the old adage: What does not kill us helps make us stronger, and this appears to apply to this pathogen as well. 

In pre-harvest pathogen control work, two natural chicken gut bacterial isolates named Paenibacillus polymyxa  and Lactobacillus salivarius and previously shown to produce  natural proteins termed bacteriocin B602 and bacteriocin OR7  that were able to control Campylobacter jejuni in chickens were used to produce these natural proteins in dried form for use as chicken feed additives. These proteins were encapsulated in a polyvinylpyrrolidone material and administered in feed to chicks which had been inoculated with with log 6 to log 7 of C. jejuni at 3 days post hatch. The chicks were given regular feed from day 1-10 then the bacteriocin containing feed for days 11-13 days. Then the birds were euthanized. The untreated chicks had C. jejuni counts of log 5 to log 6 per g of ceca content while the chicks fed for days 11-13 with either of the above bacteriocins had C. jejuni counts that were less than the minimum detectable level of 100 CFU/g of cecal content. These are very promising initial results and if sustainable for longer feeding times, this strategy may prove very helpful to reduce the Campylobacter incidence on raw retail poultry from the current level of 80-90%.

Post-Harvest

The ability of Salmonella cells to survive sub-lethal combinations of temperature, acid and time on raw chicken were evaluated by another team. Four conditions simulating possible commercial treatments were looked at: (I) room temperature water for 14 seconds; (II) 95 degree C hot water for 3 seconds; (III) 55 degree water with 2% lactic acid for 11 sec; or (IV) 95 degree hot water for 3 seconds followed by 11 seconds of the 55 degree water with the 2% lactic acid.   The virulence gene monitored for this pathogen was the hilA gene (which encodes for an epithelial cell invasion factor). One treatment in particular, the rinse at 95 degree C for 3 seconds,  gave a threefold increase in expression of this virulence gene. These results are of interest because they illustrate that a sub-lethal physical or chemical treatment may actually make a pathogen stronger and meaner.

Modeling of control measures such as heat for destruction of L. monocytogenes inoculated in solid muscle chicken products continued. Quasi-commercial process conditions of temperature, humidity and air velocity were used in a hot air steam impingement oven. Chicken

breast pieces were heated at oven air temperatures of 177 or 200 degrees C for 2 to 10 minutes and product removed at 1-minute intervals to determine cell survivor counts. After the first 2 or 5 minutes of heating at the respective temperatures,  the count reductions were 0.3 and 0.8 log CFU at 177 degrees and 1.4 and 1.8 log CFU/g at 200 degrees C.  Survivors were still detected at both air temperatures after 9 but not at 10 minutes.  Internal temperatures reached an inactivation level of about 70 degrees C in centers of breast samples at 8 minutes. Breast samples heated 10 minutes gave product yield of about 70%.

These results reinforce the need for poultry product processors to carefully monitor the temperatures and times in the coldest center parts of the products they are thermally processing to assure full destruction of this pathogen. 

The ability of natural plant extracts to control pathogen growth and survival on cooked poultry as well as preserve product quality continues. It was found for L. monocytogenes inoculated at log 6 CFU/g onto full fat turkey frankfurters that a soy protein isolate coating with nisin (10,000 IU) and green tea extract (1%, GTE) or grape seed extract (1%, GSE) at 10 degrees C over 28 days reduced pathogen counts by 1.4 or 1.3 log CFU/g as compared to the starting control day counts of log 6.5 CRU/g or by log 2.4 or 2.5 CFU/g when compared to the 28-day count for the control which had a log 7.6 CFU/g count.  For parallel tests at 4 degrees C over 28 days, the GTE and GSE treatments gave reductions of log 2.0 and 2.1 CFU/g as compared to the starting day control (log 6.5 CFU/g) and reductions of log 2.7 and 2.8 CFU/g when compared to the 28-day control count of log 7.2 CFU/g.

Electron microscopy studies showed that either the 1% GSE or GTE plus 6,400 IU of nisin caused dramatic cell wall damage to L. monocytogenes. Parallel studies with the purified chemicals from GSE, epicatechin and catechin, also showed similar effects on cells walls of this pathogen. At 6,000 ppm the GSE or GTE as compared to the control reference antioxidant called TBHQ,  when infused in raw skinless boneless chicken breast that was treated with 3 KGy dose of irradiation and cooked to normal doneness was able to prevent lipid oxidation as well as  the control. Collectively, these results point out the potential of using selected plant extracts to help control pathogen persistence in poultry products and at the same time conserve other quality attributes as well.

Solid progress in detection research strategies continued. A molecular method termed repetitive DNA sequence based polymerase chain reaction (rep PCR for short) was evaluated to distinguish among different Campylobacter jejuni isolates from different sources.  Each of four different C. jejuni isolates each showed different banding patterns, suggesting that this method will be useful for differentiating such isolates. For this purpose, the reproducibilities of the rep-PCR patterns for different C. jejuni isolate strains is being further evaluated and will be reported on later. 

In other detection research, the usefulness of a part, the B subunit, of the Campylobacter jejuni virulence gene termed the “cytolethal distending toxin” or Cdt gene for short was evaluated using PCR methods to distinguish among isolates obtained from human, chicken or turkey sources.  First, it was shown that nearly all, namely 98, 98 and 95% of the human, chicken and turkey isolates were positive for this virulence gene. However, when repeat tests over 7-day intervals were perfomed, the reproducibility of the PCR tests was unclear. There were 

negative results for 7 and up to 22 and 30% respectively for the human, turkey or chicken isolates that were previously positive by this test. The unclear reproducibility was traced to a lack of complete DNA nucleic acid base sequence homology or sameness among the isolates from these three sources for the B subunit region. These results point out the wisdom of always cross- checking the workability of a new molecular method by testing it against pathogen strains freshly isolated from nature, not just relying on stock isolates held long times in the laboratory.

Two new candidate hybridoma clones secreting monoclonal antibodies specific for Campylobacter were evaluated. Monoclonal antibodies 209B11 and 221C9 reacted with C. jejuni but not C. coli. Further, 209B11 reacted with no non-Campylobacter genera but did react with all C. jejuni strains tested (both hippurate hydrolysis-positive and -negative) and formed a single band at 43-44 KDa protein in Western blots using extracts from C. jejuni cells. Workability of this new promising monoclonal antibody to detect this pathogen under processing conditions is ongoing and will be reported later. 

A special biosensor device using a microfluidic flow cell with interdigitated array microelectrodes was coupled with a polyclonal antibody bound to a magnetic nanoparticle. This device was able in just 35 minutes to detect a minimal level of 100,000 CFU/ml of the pathogen enterohemorrhagic E. coli (EHEC).  When fluorescent quantum dots were included in this device, the sensitivity was greatly improved, being able to detect as few as 10 CFU in 1.5 hours.  The next step under development is to further refine and optimize the immobilization of the detection antibody to this biosensor platform and automate the procedure.

Conclusion

In summary, the above research results point out three general truths: (1) Pathogenic bacteria can be killed and controlled; however (2) if the physical and chemical methods of destruction are inadequate to kill all the cells, the surviving bacterial pathogens have evolved several mechanism by which they can persist in both the pre- and post-harvest arenas; and (3) the need for good detection methods for pathogens to confirm adequate destruction/control will remain with us as long as these pathogens persist in our biosphere.

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 Iowa State University

James Dickson, Iowa State University

 James S. Dickson

The Iowa State University component of the Food Safety Consortium funded six research projects and two equipment grants in 2005-2006. Research scientists representing several academic departments at the university, as well as USDA-ARS and HHS-FDA, were involved. The primary basis for research under this research program has been the enhancement of the safety of pork and pork products, although one project did address the significance of bacteremia in turkeys.  The research projects encompassed many aspects of food safety as it is currently viewed, from the farm to the consumer.

Animal production: Dr. Zhang’s research group evaluated the presence of antimicrobial resistant Campylobacters in live pigs. In this project, he investigated the antimicrobial resistance profiles of fecal Campylobacter isolates (n= 194) obtained from a swine farm at different production stages including piglets (n=94), midway piglets (n=21), end-nursery piglets (n=38), mid-finisher pigs (n=23), and end-finisher pigs (n=18). Using the standardized agar dilution test, susceptibility of the Campylobacter isolates to antimicrobial agents including gentamicin, meropenem, ciprofloxacin, erythromycin, and doxycycline were determined according to the CLSI recommendation. Among the examined C. coli isolates, overall resistance rates of 0, 0, 0, 56.7%, and 39.2% were detected against gentamicin, meropenem, ciprofloxacin, erythromycin, and doxycycline, respectively. The following resistance rates were observed against erythromycin and doxycycline, respectively, at each stage of the production: piglets (37.2%, 52.1%), midway piglets (52.4%, 85.7%), end-nursery piglets (21.1%, 78.9%), mid-finishers (73.9%, 34.8%), and end-finishers (27.8%, 27.8%). These results indicated that although ciprofloxacin resistance was not present in C. coli isolates from swine, resistance to other clinically important drugs (e.g., erythromycin and doxycycline) was common, occurring at multiple stages of the production cycle. These findings plus ongoing studies reveal new information on the epidemiology of antibiotic resistant Campylobacter in swine, which will be useful for reducing the occurrence and transmission of antibiotic resistant foodborne pathogens. 

Dr. Nancy Cornick’s research group has previously shown that E. coli O157:H7 can be transmitted between inoculated donor pigs and naïve pigs that share the same pen, food and water sources. In their current research, they have demonstrated that the transmission of E. coli O157:H7 can occur between naïve pigs that have no direct contact with infected pigs. The challenge strain was recovered from 3/3 naïve pigs sharing the pen with the donor, from 4/4 naïve pigs in adjacent pens with nose-to-nose contact, from 3/3 naïve pigs adjacent to the first pair of naïve pigs (no nose-to-nose contact with the donor) and from 5/6 naïve pigs that did not have contact with any of the other pig pairs. They also recovered E. coli O157:H7 from 3/14 air samples collected during the third replicate of the experiment. The air samples were positive by enrichment culture with magnetic beads, but not by direct culture. These results demonstrate that E. coli O157:H7 is readily transmitted amongst swine and suggest that it may be aerosolized by colonized animals and/or cleaning of contaminated pen surfaces.

Methodology: Dr. Harris’ research group improved a quantitative real-time PCR method for the detection of Salmonella in swine tissues. Comparison of qPCR and MPN revealed that viable Salmonella in the spiked fecal samples was within one log of the total amount of Salmonella in the samples.  In addition, they researched the identification of Salmonella serotypes using pulsed-field gel electrophoresis of conserved Xba1 fragments. Swine Salmonella isolates were analyzed via pulsed-field gel electrophoresis (PFGE) with Xba1. PFGE subtypes were analyzed by cluster analysis and compared to conventional serotyping results. The analysis showed a correlation of serotype to PFGE subtype. In addition, conserved fragments were identified within the restriction patterns that were unique to each serotype.

Dr. Brehm-Stecher’s research group evaluated rapid flow cytometric detection of Salmonella and Listeria monocytogenes in pork. Fluorescence in situ hybridization (FISH) utilizes fluorescently labeled oligomer probes re reacted with ribosomal RNA present in whole microbial cells, leading to the selective “phylogenetic staining” of target pathogens. As a whole cell fluorescent method, FISH can be combined with flow cytometry to enable the rapid detection and enumeration of specific cells in complex samples. Both pathogens were directly detectable at high levels of contamination (106 CFU/g) in cubed pork (Salmonella) and pork franks (Listeria). Unambiguous detection of both pathogens at low levels (102 CFU/g) was also possible after only 8 hours of non-selective pre-enrichment in either buffered peptone water or universal pre-enrichment broth.

Interventions: Dr. Sebranek’s research group evaluated the effects of antimicrobial inhibitors and modified atmosphere on Salmonella and Listeria monocytogenes on modified atmosphere pork. Lactate and diacetate in combination with high levels of carbon dioxide were investigated for effects on initial Salmonella Typhimurium and Listeria monocytogenes numbers and suppression of growth of survivors.  The proposed hypothesis is that combining ingredients (lactate and diacetate) with high carbon dioxide in modified atmosphere packages (MAP) for pork products will not only reduce the initial number of microbial pathogens but also extend the lag phase of the growth of the survivors to achieve improved overall control of the pathogens. 

Consumer Information: The Consortium continues to help fund the food safety web page designed and maintained under the direction of Mr. Jason Ellis. The Food Safety Consortium (FSC) consumer web-site project continues to receive a significant number of site visits and be recognized for its work. More than 597,000 visitors have accessed the food safety web site home page or one of its links over the past year. Visitors accessed our site with an average of approximately 10 minutes per visit.

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Kansas State University

Curtis Kastner, Kansas State University

Curtis Kastner

The primary focus of the work at Kansas State University continues to be methods development for the isolation, detection, and quantification of microbial and chemical hazards and the elimination of those hazards. However, that research has also most recently resulted in significant information and technology transfer relative to risk assessment, economic, policy, and trade information and has laid the foundation for reaping additional insights in those areas. Furthermore, our food safety work has prepared us to address food security that may be the result of bioterrorism and/or natural disasters. Thus, funding for the Consortium has fortunately prepared us to address and communicate solutions to the interdisciplinary challenges in today’s changing world.

 Continued funding for the consortium will allow us to fully capitalize on the recent interdisciplinary applications synergy and that will insure optimum utilization of Consortium outputs to comprehensively address food security as well as food safety issues. The integration of Consortium outputs continues to be adapted to address today’s challenges, and based on that past performance, will be ready for tomorrow’s challenges. That readiness can only be insured by continuous support, which has and will continue to attract other funding and has consistently leveraged that funding to support the critical Consortium base support.

Highlights and implications for this annual report include examples that represent the spectrum of K-State’s initiatives.

Microbial Food Safety

Effective microbiological sampling equipment is needed to determine the quality and safety of foods. The Stomacher sample processor was introduced to laboratories in 1972. However, its “crushing action” caused a significant amount of debris to remain in diluents. The Pulsifier was developed for sample processing with less debris and ease of sample manipulation. By using a combination of shock waves and stirring action, the Pulsifier has provided clearer suspensions for vegetables and lean meat tissues.

Effective microbiological techniques that enumerate microorganisms are needed to determine the quality and safety of foods. Sublethally injured pathogens can recover from processing and treatment injury; and because of selective agents in selective agars, microorganisms are underreported. Kang and Fung (1999) developed the thin agar layer (TAL) method as a one step laboratory preparation for the resuscitation of cold-, heat-, salt-, and acid-injured pathogens and research is needed to validate its use in meats, such as hot dogs. Our objective was to use a meat model to compare the recovery of Listeria monocytogenes on Modified Oxford (MOX) agar and TAL-MOX agar. Our results indicated that TAL-MOX agar was more effective for recovering L. monocytogenes than MOX agar used alone. The TAL-MOX had a 47% higher bacterial cell recovery as compared to MOX used alone. This research provides validation of the TAL technique for the improved enumeration of microorganisms from hot dogs.

Consumer interest has recently focused on the use of “natural antimicrobials” to control food pathogens. Because of this, the development of natural treatments to ensure the safety of meats is of interest to both consumers and the food industry. Tea and honey are believed to contain several compounds that contribute to their antimicrobial activity and research is needed in this area. Our objective was to determine if a honey and tea extract combination could inhibit Listeria monocytogenes in a liquid and meat model. Our results indicated that Jasmine tea combined with honey had the highest antimicrobial activity. This treatment decreased L. monocytogenes ca. 3 log CFU/ml, compared to the control on day 5. Hot dogs treated with Jasmine tea (0.1% v/cm2) combined with honey (0.2% c/cm2) decreased L. monocytogenes 2.1 log CFU/cm2 by day 14 (P<0.05). These results suggest that in a liquid and meat model our honey and tea extract combination was effective in inhibiting L. monocytogenes. The application of this treatment was also investigated on sliced turkey with positive results as a surface wash, and may be significant for improving the safety of meats.

Lactate and non-lactate formulated frankfurters were dipped in sodium lactate and acidified calcium sulfate then inoculated with Listeria monocytogenes. After storage of the vacuum packaged frankfurters for 30 days at 4 ºC, the frankfurters were then individually placed into zip lock bags and stored for an additional three weeks at 7 degrees C. Profiles of total aerobic counts as well as L. monocytogenes counts were monitored. The results indicated that sodium lactate dip produced frankfurters that had lower total aerobic counts and lower inoculated L. monocytogenes counts compared with acidified calcium sulfate treatment and controls that had no dip. Use of lactate formulation in frankfurters resulted in lower bacterial counts of both natural microflora and inoculated L. monocytogenes in frankfurters after prolonged storage at 4 degrees C.

USDA/FSIS issued “Compliance Guidelines for Meat and Poultry Jerky Produced by Small and Very Small Plants,” that provides processing parameters for controlling pathogens such as Escherichia coli O157:H7 and Salmonella spp. The objective of this study was to determine the effects of typical thermal processing temperatures and times on reducing E. coli O157:H7 and Salmonella spp. in chopped and formed beef jerky. Initial raw batter E. coli O157:H7 and Salmonella spp. populations were approximately 7.3 log CFU/g. When the smokehouse dry bulb (D.B.) temperature was 55.6 degrees C and relative humidity (R.H.) was approximately 10% for 44 min followed by 77.8 degrees C D.B. and R.H. at approximately 10% for 46 minutes, ≥5 log reductions were observed for both E. coli O157:H7 and Salmonella spp. populations. However, and additional heating/drying phase of 3 hours with smokehouse D.B at 77.8ºC was required to achieve a moisture-to-protein ration (MPR) of 0.77:1, which is slightly higher than the 0.75:1 MPR as required by USDA/FSIS for jerky products. Furthermore, additional heating of 3.5 hours was needed to achieve Salmonella spp. log reductions of ≥6.5 as required by USDA/FSIS, which resulted also in MPR values of 0.45:1 and water activity levels of 0.59.

Another validation study was designed to evaluate quality, shelf life, and antimicrobial effects of controlled phase carbon dioxide (CPCO2) on beef trimmings destined for ground beef. Using 1500 psi CPCO2for 15 min achieved the highest lethality (P<0.05) in challenged beef trimmings (TR) and ground beef (GR). Total Plate Count (TPC), Generic E. coli (GEC), E. coli O157:H7 (O157), and Salmonella spp (SS) reached 0.83, 0.96, 1.00, and 1.06 log reductions, respectively. Bacterial reductions in ground beef (GR) were similar (P>0.05) to beef trimmings (TR). Ground beef patties manufactured from treated beef trimmings scored higher (P< 0.05) values for tenderness when compared to non-treated counterparts. At 750 psi CPCO2 appeared to have worse scores for juiciness, beef flavor intensity, or off flavor intensity (P<0.05) than the 1500 psi CPCO2 treatment or the control.

Ongoing investigations were designed to investigate the susceptible and resistance profiles for more than 1,000 isolates of generic Escherichia coli and Enterobacter spp. collected from lagoon water of “commercial and natural” bovine feedlots located throughout the Midwest. For these studies commercial refers to feedlots that use tretacycline while natural refers to feedlots that do not use antibiotics. Lagoon water of commercial feedlots contained more resistant generic E. coli isolates than that of lagoon water of natural feedlots. These results suggest that antimicrobial usage may contribute to the presence of resistance isolates in food-animal production environments. Lagoon water of commercial feedlots contained a greater percentage of resistant generic E. coli isolates than that of lagoon water of natural feedlots. In addition, this study found that all (n=364) cultures from lagoon waters of commercial and natural feedlots exhibited resistance to ≥ 5 antibiotics of the 21 evaluated. These results suggest that antimicrobial usage may contribute to the present of resistant isolates in food-animal production environments.

Chemical Food Safety

Alkylcyclobutanones are radiolytic products that are formed when triglycerides are subjected to ionizing radiation. Thus the objectives of this experiment were to quantify 2-dodecyclobutanone (2-DCB) formed from palmatic acid in feces and adipose tissue of rats and to check for metabolites of 2-DCB in the urine. Six female Sprague-Dawley rats were administered 2-DCB (5 mg/day) in corn oil for five days gavage. Six control rats did not receive 2-DCB. Hexane extracts of feces and adipose tissue were analyzed by gas chromatography-mass spectrometry (GC-MS). Urine with, and without, added -glucoronidase was monitored for glucuronide complexes by hexane extraction and GC-MS.

The total amount of 2-DCB recovered in feces was 1.78 ± 0.63 mg at the end of 5 days which presents between 3-11% of the total 2-DCB administered. The total amount recovered in the adipose tissue was 0.08 ± 0.01 mg which was about 0.33% of the total 2-βDCB administered. No metabolites were recovered in any of the urine extracts. The results show that at most 11% of the 2-DCB was recovered unchanged in the feces and adipose tissue. This indicates that either most of 2-DCB is metabolized, and rapidly eliminated from the body, or stored at sites other than adipose tissue.

Ammonia-ion selective electrode (ISE), indophenol method, salicylate method, ammonia test kit from Aquarium Pharmaceutical, and the Reflectoquant® test strips were evaluated to determine which of these methods can be used for in-plant rapid testing of potentially contaminated muscle food products. In addition, the ammonia background of 11 meat products were measured using the ISE assay. The results indicates that both ISE and indophenol method can be used for determination of ammonia in contaminated muscle food products. The recovery of the ISE-perchloric acid method ranged from 90% to 110% with a coefficient of variation (CV) of 7.6% or less. The recovery of the indophenol-perchloric acid method ranged from 95% to 113% and the CV was 8.3% or less. The recoveries of the other methods were lower with higher coefficients of variation.

Heterocylic amines (HCAs), a group of chemicals formed during high temperature cooking of meat and fish, are potent mutagens and are suspected to play a role in colorectal cancer in human. Marinating steaks with different commercial marinades containing rosemary extracts can offer a practical way to reduce HCAs formation.

Economic Implications of GM Wheat, Policy and Trade

The impact of introducing genetically modified (GM) wheat will depend on acceptance in both the export and domestic markets. To date U.S. consumers have been relatively unconcerned about GM food ingredients. But consumers may be more concerned about GM wheat products than about ingredients derived from GM soybeans or corn, and thus may be more susceptible to be influenced by campaigns by consumer activists that focus on potential risks from GM wheat. Our objective was to investigate consumer acceptance of GM wheat products, and to quantify the extent to which purchase decisions are influenced by information about the risks of biotechnology, and information about current GM content in wheat products. Respondents were largely unfamiliar with the concept of GM foods with 65% indicating that they had either “never heard of” or “had heard a little” about them. However, a majority of respondents (68%) indicated they would accept GM wheat based products. Furthermore, almost three quarters would not pay more to avoid GM wheat. Results from regression analysis indicated that socio-demographic characteristics do not have a significant influence on acceptance. Individuals receiving information about a negative perspective on GM were less likely to accept GM wheat and were willing to pay 12 cents more per loaf of bread to avoid GM wheat. Providing information about GM ingredients currently in wheat products had no impact on acceptance of GM wheat.

Initial policy and trade initiatives in process include research on regionalism and preferential trade agreements, in contrast to merely multilateral approaches to cooperation in food safety and security; conducting research regarding “disease-free” regions, zones, and compartments (which in North America are receiving increased policy attention); continuing research on the historical roles played by export-certification and niche markets during trade disputes over, for example, BSE; revising research regarding 19th Century transatlantic disputes over food safety and animal disease; and exploring compiling a biographical series on important, modern-day and historical policy actors involved with food safety, border security, animal disease, and international trade.

Distance Education

Nine credit courses in food science and food safety have been developed for distance education. These courses integrate interactive components to create an experiential learning environment similar to on-campus courses. Many of these courses have been captured with an enhanced media system while faculty are teaching students on-campus. Student evaluations of the courses have been positive and supportive for the future creating of additional interactive components and courses as part of a food safety and security curriculum. The courses integrate results from the Consortium along with research from other sources.

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