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a. To determine the effects of dietary and environmental conditions and animal handling on the oxidative stress of animal and the development of pale, soft and exudative conditions in meat. b. To establish procedures to predict meat quality with Raman Spectrosensing and proteomics. c. To determine the ingoing and residual concentrations of nitrite that are most critical for affecting growth of bacterial pathogens (using L. monocytogenes and C. perfringens as representatives)in a simulated natural/organic processed meat model system. d. To investigate cherry powder and lemon powder effects on the antimicrobial impact of nitrite in natural/organic cured meats and to investigate combinations of nitrite with cranberry concentrate and other effective natural antimicrobials for additive or synergistic antimicrobial effects in natural/organic cured meats. e. To reduce the level of microbiological contamination on animal carcasses during processing, reduce the level of microbiological contamination on processed meat products and develop processes or technologies to achieve these objectives which are compatible with small and very small processing establishments. f. To investigate the effects of non-thermal (irradiation and high hydrostatic pressure) processing on the sensory and textural properties of processed meat products.
Non-Technical Summary: This project will try to further define the external and internal factors that affect meat tenderness, color, and moisture and seek ways to improve those traits, assess novel non-meat ingredients and new processing technologies in processed meats, assess the risks of pathogenic bacteria in processed meats, and characterize the quality changes in irradiated processed meats. <P> Approach: The breast muscle will be used to determine oxidation of SR proteins, sarcoplasmic reticulum (SR) Ca++-ATPase activity, pH, lactate, ATP, and glycogen content in the muscle. pH will be determined after homogenizing with 9 volumes of 150 mM KCl-5 mM iodoacetate solution. Lactate, ATP, and glycogen will be determined using enzymatic methods. Breast muscles will be separated from the carcasses 24 h after slaughter and used to measure color, water holding capacity, cooking loss, and ultimate pH to determine PSE conditions of breast meat. Color will be measured using a Minolta color meter and water holding capacity will be measured using a centrifugation method. One chop will be reserved for Raman Spectroscopy. This chop will be stored at 2 C and will be scanned each day (day 2-day 14). Raman spectral measurement will be conducted using a DXR Raman microscope using a 780 nm infrared laser as excitation source to minimize background fluorescence. Raman spectra will be collected at 1 cm-1 resolution at 50-1800 cm-1. A trained sensory panel will determine sensory tenderness, chewiness, juiciness, flavor and off-flavor on fresh pork loin chops from each loin aged 2 and 14 days postmortem. Chops prepared in the same manner will be used to determine star probe values on chops from each loin aged 2, 7 and 14 days postmortem. Postmortem degradation of desmin and troponin-T will be determined on samples aged 2, and 7 days postmortem. Lean ground pork will be blended with distilled water, 2% salt, 0.2% celery powder and a commercial nitrate-reducing culture as is typically done in the natural curing process. Samples will be inoculated with a 5-strain mixed culture of L. monocytogenes. Samples will be held at 7-10 C for up to 6 weeks with bi-weekly analyses conducted. For C. perfringens, a 4-strain mixed culture will be used. Identification of Hazards: Research will focus on the identification of food safety hazards, which are reasonably likely to occur, and also to estimate their frequency or level of occurrence. It is important to complete a hazard analysis to assure that the research is addressing the specific needs. Evaluation of Hazards: Research will focus on the biological characteristics of the hazards, and attempt to identify the most promising methods of control. Development of Interventions: Based on the identification of the food safety hazards and an evaluation of these hazards, interventions will be designed to meet the specific hazards. Development of Interventions suitable for small and very small establishments: Based on the established principles of the identified interventions, the interventions will be adapted to the unique operating environment of the small and very small processors. Technology transfer: The information will be transferred to meat processors by means of extension publication, workshops, short courses and individual interaction with small and very small processors. Coarse ground smoke sausage will be produced with various combinations of beef and pork mixtures including 100% beef and 100% pork, irradiated at three different doses and stored for two weeks. Sensory, chemical and physical characteristics will be measured.