Joseph G. Sebranek

Comparison of a natural rosemary extract and BHA/BHT for relative antioxidant effectiveness in pork sausage

A commercial rosemary extract was evaluated for antioxidant effectiveness at concentrations of 1500 and 2500 ppm in frozen and precooked-frozen pork sausage, and from 500 to 3000 ppm in refrigerated, fresh pork sausage. Thiobarbituric acid-reactive substances (TBARS), objective color values and sensory panel scores, were assessed. For refrigerated sausage, the rosemary extract at 2500 ppm was equally effective as butylated hydroxy anisole (BHA)/butylated hydroxy toluene (BHT). Similarly, the rosemary extract was equally effective as BHA/BHT in maintaining low TBARS values of precooked-frozen sausage. However, the rosemary extract was more effective than BHA/BHT for preventing increased TBARS values or loss of red color in raw frozen sausage.

High-oxygen modified atmosphere packaging system induces lipid and myoglobin oxidation and protein polymerization.

Beef steaks from longissimus lumborum, semimembranosus, and adductor muscles (n=10; respectively) were cut at 24h postmortem, randomly assigned to either high-oxygen modified atmosphere packaging (HiOx-MAP; 80% O(2), 20% CO(2)) or vacuum (VAC), and displayed for 9days at 1 degrees C. HiOx-MAP packaged beef steaks had a rapid increase in lipid oxidation and a decrease in color stability during display. The steaks in HiOx-MAP had significantly lower tenderness and juiciness scores, and higher off-flavor scores compared to steaks in VAC. HiOx-MAP condition did not affect the postmortem degradation of troponin-T or desmin. Furthermore, autolysis of micro-calpain was not influenced by packaging. SDS-PAGE, immunoblotting, and diagonal-PAGE revealed oxidative cross-linking of myosin heavy chain in meat packaged in HiOx-MAP. These results suggest that the HiOx-MAP system may negatively affect meat quality characteristics by inducing lipid and myoglobin oxidation and cross-linking/aggregation of myosin by protein oxidation.

A Survey of Commercially Available Broilers Marketed as Organic, Free-Range, and Conventional Broilers for Cooked Meat Yields, Meat Composition, and Relative Value

The objective of this survey was to investigate qualitative and quantitative properties of meat from organic, free-range, and conventional broilers as currently provided to consumers. Fifteen broilers from 4 suppliers of each type were evaluated for raw meat yield, cooked meat yield, proximate composition, pH, color, lipid oxidation, fatty acid composition, and sensory attributes. Organic broilers yielded more dark (thigh) meat (P < 0.05) than free-range or conventional, when compared on a raw-meat basis, but conventional and free-range broilers yielded more (P < 0.05) cooked light (breast) meat than organic. Protein content of organic breast and thigh meat was greater (P < 0.05) than conventional in the raw and the cooked meat comparisons. The pH of breast meat from organic broilers was higher (P < 0.05) than free-range or conventional. Organic breast and thigh meat was less yellow (P < 0.05) than free-range or conventional. Fatty acid analysis showed that organic breasts and thighs were lower (P < 0.05) in saturated and monounsaturated fatty acids and higher (P < 0.05) in polyunsaturated fatty acids than free-range and conventional broilers. Shear force measurements were less (P < 0.05) for both breast and thigh meat from conventional broilers relative to free-range and organic broilers. Sensory panel results indicated that thighs from conventional broilers were more tender (P < 0.05) and less chewy (P < 0.05) than thighs from free-range and organic broilers, whereas other sensory properties did not differ. At the time of the study, March through May of 2006, the average retail prices for US broilers were USD 3.19, USD 2.78, and USD 1.29 per pound (USD 7.03, USD 6.13, and USD 2.84/kg) for organic, free-range, and conventional, respectively. Whereas a difference in the fatty acid composition was the largest difference observed between retail broilers in this survey, it is important to note that diets and production environments within the study were not controlled. It is apparent that the market prices for broilers at the time of this study are not fully reflected in the quantitative and qualitative measurements included in this study. It appears that consumers may be placing significant value on more intangible attributes associated with broilers marketed as organic and free-range chicken than on those attributes measured in this study.

Irradiation and packaging of fresh meat and poultry

Extensive research on the irradiation of fresh meat and poultry has been carried out during the past 40 years; yet there is a need for consideration of combined use with other technologies such as modified atmosphere (MA) packaging. Some of the past work has focused on spoilage microorganisms and pathogens, whereas other reports emphasize the sensory quality of fresh meat and poultry. Reports published indicate that the effects of irradiation in conjunction with packaging vary depending upon the kind of meat and poultry and the atmosphere composition in the package. Irradiation may result in off-flavor and/or odor and discoloration of fresh meat and poultry in packages containing air (oxygen). One concern is that pathogens may grow and/or produce toxins in irradiated meat or poultry packaged using modified atmospheres because of a lack of competing organisms. This is of even greater concern if spoilage is suppressed and does not provide the usual warning signals. On the other hand, even though there is some evidence of the growth of pathogens in temperature-abuse conditions, most reports have indicated that spoilage preceded toxin production. Therefore, considering the sensory quality and concerns for safety, the effects of irradiation in combination with vacuum or MA packaging of fresh meat and poultry should be studied further. More complete information is needed to ensure the appropriate use of vacuum or MA packaging in combination with irradiation for the safety of fresh meat and poultry.

Beyond celery and starter culture: advances in natural/organic curing processes in the United States.

Over the past 10years there has been ongoing development of curing processes with natural ingredients designed to meet consumer demand and regulatory requirements for natural and organic processed meats. Initially, these processes utilized celery concentrates with a high nitrate content combined with a nitrate-reducing starter culture. Subsequent advances included celery concentrates with the nitrate converted to nitrite by suppliers. Further, as questions developed concerning reduced concentration of preservatives and the microbiological safety of these processed meats, additional advances have resulted in a wide variety of ingredients and processes designed to provide supplementary antimicrobial effects for improved product safety.

Gelation characteristics of muscle proteins from pale, soft, exudative (PSE) pork

Thermally induced protein gels were made by using extracted salt-soluble proteins from normal pigs and stress-susceptible pigs determined to have pale, soft, exudative (PSE) muscle. Effects of heating rates (17,39 and 93° C/h) at various protein concentrations (23, 34, 48 and 54 mg/ml) were evaluated. Gel strength of PSE extracts was 45% of the controls at equivalent protein concentration. Gel strength of normal and PSE-muscle protein gels from the first compression curve increased with increasing protein concentrations at all heating rates; however, gel strength was greater for slow heating rates than for fast heating rates in both PSE and normal samples. Percent water loss was greater for PSE extracts than for controls at the same protein concentration. Losses of 47% and 36% for PSE and controls, respectively, were observed at a a protein level of 54 mg/ml protein. There was no heating rate effect on water losses in either case. Protein loss was less, for both PSE and control, at low protein concentrations than at high protein content in the range studied. Slow heating rates resulted in less protein loss, for both PSE and control, whereas faster heating rates gave greater protein losses in the exuded water.

Combining pediocin with postpackaging irradiation for control of Listeria monocytogenes on frankfurters

Frankfurters, in 1-link, 5-link, or 10-link packages, were surface inoculated with a five-strain mixture of Listeria monocytogenes (3.40 or 5.20 log CFU/g) after treatment with 3,000 arbitrary units (AU) or 6,000 AU of pediocin (in ALTA 2341) per link. The frankfurters were vacuum packaged, after which the 1-link and 5-link packages were irradiated at 1.2 or 2.3 kGy and the 10-link packages were irradiated at 1.4 or 3.5 kGy. L. monocytogenes was enumerated following the treatments. Selected treatments were subsequently evaluated during storage at 4, 10, and 25 degrees C for up to 12 weeks. Combination of pediocin with postpackaging irradiation at 1.2 kGy or more was necessary to achieve a 50% reduction of L. monocytogenes on frankfurters in 1-link or 5-link packages. The combination of 6,000 AU of pediocin and irradiation at 2.3 kGy or more was effective in all package sizes for inhibition of the pathogen for 12 weeks at 4 or 10 degrees C. There was a synergistic effect between pediocin and irradiation for inhibition of L. monocytogenes. Storage at 4 degrees C enhanced the antilisterial effects of the treatment combinations, with little or no growth of the pathogen in 1-link or 5-link packages during 12 weeks of storage. In general, these treatments did not affect the sensory quality of frankfurters.

Effects of high hydrostatic pressure and varying concentrations of sodium nitrite from traditional and vegetable-based sources on the growth of Listeria monocytogenes on ready-to-eat (RTE) sliced ham

The objective of this study was to determine the effect the source of added nitrite and high hydrostatic pressure (HHP) had on the growth of Listeria monocytogenes on ready-to-eat (RTE) sliced ham. Use of 600MPa HHP for 3min resulted in an immediate 3.9-4.3log CFU/g reduction in L. monocytogenes numbers, while use of 400MPa HHP (3min) provided less than 1log CFU/g reduction. With the 600MPa HHP treatment, sliced ham with a conventional concentration of sodium nitrite (200ppm) was not different in L. monocytogenes growth from use with 50 or 100ppm of sodium nitrite in pre-converted celery powder. Instrumental color values as well as residual nitrite and residual nitrate concentrations for cured (sodium nitrite and nitrite from celery powder) and uncured ham formulations are discussed.

The effect of high hydrostatic pressure, sodium nitrite and salt concentration on the growth of Listeria monocytogenes on RTE ham and turkey.

Growth of Listeria monocytogenes was evaluated for up to 182 days after inoculation on ready-to-eat (RTE) sliced ham and turkey breast formulated with sodium nitrite (0 or 200 ppm), sodium chloride (1.8% or 2.4%), and treated (no treatment or 600 MPa) with high hydrostatic pressure (HHP). HHP at 600 MPa for 3 min resulted in a 3.85-4.35 log CFU/g reduction in L. monocytogenes. With formulations at similar proximate analyses, one of the evaluation days (day 21) without HHP showed significantly greater growth of L. monocytogenes in ham than in turkey breast, but there were no significant differences on other evaluation days or with HHP. There were no differences in growth of L. monocytogenes due to sodium chloride level. Sodium nitrite provided a small, but significant inhibition of L. monocytogenes without HHP, but addition of sodium nitrite did not significantly affect growth of L. monocytogenes with use of HHP.

Inhibitory Effects of Organic Acid Salts for Control of Listeria monocytogenes on Frankfurters

Sodium diacetate (SD), sodium diacetate plus potassium benzoate (SD-PB), and sodium lactate plus sodium diacetate plus potassium benzoate (SL-SD-PB) were selected for initial effectiveness against Listeria monocytogenes on frankfurters. Treatments were evaluated at -2.2, 1.1, 4.4, 10.0, and 12.8 degrees C for up to 90 days. The compounds were applied as 3 or 6% (total concentration) dipping solutions for surface treatment of the frankfurters. The treated frankfurters were inoculated with a five-strain cocktail of L. monocytogenes (Scott A 4b, H7764 1/2a, H7962 4b, H7762 4b, and H7969 4b) using 1 ml of 10(4) cells for each 90.8-g package of two frankfurters. The maximum population of L. monocytogenes was decreased and generation time and lag phase were increased after surface treatments with 6% SD, 6% SL-SD-PB, 3% SD-PB, and 6% SD-PB solutions at 1.1 degrees C. Surface treatment of frankfurters with SD at 6% was more effective for inhibiting L. monocytogenes growth than were the other treatments. Under the conditions of this study, L. monocytogenes survived in refrigerated storage even in the presence of the additives tested.