Peach skin powder inhibits oxidation in cooked turkey meat.

The objective of this study was to measure the antioxidant activity of peach skin and test the antioxidant effect of peach skin powder on cooked ground turkey meat during 12 d of refrigerated storage. Antioxidant activity of 3 cultivars of peaches grown in South Carolina was first evaluated by 3 antioxidant assays. The peach variety O'Henry showed the greatest antioxidant effect and therefore was used for further study. Two levels of peach skin powder (0.5%, 1%) and 0.01% butylated hydroxylanisole (BHA) were applied to ground turkey meat. Oxidation of cooked turkey meat was measured by detection of hexanal using gas chromatography-mass spectrometry. Results indicated that all levels of peach skin powder used in this study had an antioxidant effect on ground turkey with a greater effect at the higher concentration. O'Henry peach skin powder was as effective as BHA in preventing oxidation at the levels tested.

Antioxidant activity of carnosine extracted from various poultry tissues.

The aim of the present research was 1) to extract carnosine from different low economic value poultry tissues and 2) to measure their antioxidant activities using different analytical methods. Low economic value poultry tissues such as the head, liver, lungs, tail, gizzard, brain, and heart were used in this study. Results have indicated that carnosine was present in all the tissue samples investigated. The liver had the highest (102.29 mg/g) and brain the lowest carnosine content (0.95 mg/g; P ≤ 0.05). Except for the brain, all tissue ultrafiltrates and reconstituted dry powders showed TBA reactive species inhibition ranging from 20.87 to 39.57% and 5.66 -14.47%, respectively. Free radical scavenging activity of ultrafiltrate from all tissues samples ranged from 25.11 to 79.38%, whereas this activity was higher (29.76 to 84.05%) in the reconstituted dry powder of all tissue samples. Conclusions include that extraction of bioactive dipeptide carnosine can be exploited from low economic value poultry tissues to increase the economy of the poultry industry.

Survival of artificially inoculated Escherichia coli and Salmonella Typhimurium on the surface of raw poultry products subjected to crust freezing.

Escherichia coli and Salmonella spp. are ubiquitous in the poultry production environment, and hence, their transmission to poultry products is of concern. Industry has widely used freezing as a strategy to halt pathogen growth, and more recently, crust freezing has been suggested as a means to improve mechanical operations, quality, and safety of poultry products. The purpose of this study was to evaluate the effect of crust freezing on the survival of Escherichia coli and Salmonella Typhimurium that were artificially inoculated on the surface of raw poultry products with or without adhering skin. Ampicillin-resistant (AR) E. coli JM 109 and nalidixic acid-resistant (NAR) Salmonella Typhimurium were used in the experiments. A set of cultures was subjected to cold-shock stress by storage at 4°C for 10 d. After being either cold-shocked or non-cold-shocked, commercial chicken breasts without skin and chicken thighs with skin were inoculated in separate experiments with each bacterium. Samples were crust frozen at -85°C for 20 min or completely frozen at -85°C for 60 min. The E. coli and Salmonella Typhimurium were recovered on appropriate selective and nonselective media containing the corresponding antibiotic. Log reductions and extent of injury were calculated and treatments were compared using ANOVA. No significant differences were observed in the reduction of cold-shocked or non-cold-shocked bacteria on products with or without skin that were crust or completely frozen. The average reduction for E. coli was 0.15 log(10) cfu/mL of rinse, and for Salmonella Typhimurium 0.10 log(10) cfu/mL of rinse; therefore, none of the final reductions were greater than the desired target (1 log). Bacterial cell injury was not significantly different (P > 0.05) among any of the treatments. Data showed no practical significance for initial reduction of these pathogens from crust freezing and thus, this technology should not be considered as a strategy for the reduction of E. coli and Salmonella Typhimurium on poultry.

Effect of stress on carnosine levels in brain, breast, and thigh of broilers.

The objective of the present study was to compare carnosine levels in tissues of broilers under stress conditions with those of broilers under nonstress conditions. Blood heterophil:lymphocyte ratio and corticosterone levels were measured as indicators of the level of stress. Corticosterone levels of stressed broilers (24,358.67 pg/mL) were 10-fold higher (P = 0.002) than those of nonstressed broilers (2,275.46 pg/mL). However, no difference (P = 0.29) was found in heterophil:lymphocyte ratio of nonstressed (0.29) and stressed (0.31) birds. Carnosine content in breast of stressed birds (17.39 mg/g) was 10 times higher (P = 0.005) than that of nonstressed birds (1.85 mg/g). Carnosine content in thigh of stressed birds (21.25 mg/g) was approximately 2-fold higher (P = 0.001) than that of nonstressed birds (11.10 mg/g). Carnosine content in brain of stressed birds did not differ (P = 0.82) from that of nonstressed birds. Based on the present study, muscle carnosine recovery levels increase during short-term stress, whereas levels in the brain are not affected.

Antimicrobial gelatin films reduce Listeria monocytogenes on turkey bologna.

Antimicrobial films and coatings may be useful to inhibit bacterial growth on ready-to-eat poultry meats. Nisaplin and Guardian CS1-50 were added at 6 and 5 different concentrations to cast gelatin-based films to inhibit Listeria monocytogenes inoculated in liquid media, solid media, and on bologna. Color properties and antimicrobial activity were measured during storage of films at 21 degrees C+/-2. For the shelf-life study on bologna, color change and antimicrobial effect of 0.5% Nisaplin and 1% Guardian were measured. The intensity of yellowness in films increased as both Nisaplin and Guardian concentrations increased. Film tensile strength and percentage of elongation decreased as incorporation of antimicrobials increased. All 6 Nisaplin films showed a 3-log reduction after 1 h and a 6-log reduction after 6 to 8 h compared with control, in which there was no reduction in Listeria population in 0.1% peptone water. Two Guardian films (0.5 and 1%) showed approximately a 3-log reduction in 24 h. In the solid media, all Nisaplin films (except 0.05%) and all Guardian films inhibited L. monocytogenes after 48 h of incubation. Nisaplin films and all Guardian films still showed antilisterial effects after 16 wk of storage in the solid media. Total color difference compared with control (bologna) decreased from highest to lowest in the following order: 1% Guardian>control (film with no antimicrobial)>0.5% Nisaplin film>bologna. Both 0.5% Nisaplin film (4 log lower than control) and 1% Guardian film (3 log lower than control) effectively inhibited L. monocytogenes on bologna during storage at 4 degrees C for 56 d.

Effect of commercial rosemary oleoresin preparations on ground chicken thigh meat quality packaged in a high-oxygen atmosphere.

Four commercial rosemary oleoresin preparations were added to ground chicken thigh meat at the recommended levels of the manufacturer then packaged in 80% O(2)-20% CO(2) modified atmosphere trays. The rosemary preparations differed in oil and water solubility, dispersion properties, or both. Addition of rosemary to ground chicken had an overall positive effect on raw meat appearance during storage and cooked meat flavor. No effect on bacterial growth was observed due to rosemary addition. However, oxidation was slowed in meat with added rosemary as indicated by lower TBA values, lower hexanal concentrations, and sensory scores. Color (redness) was more stable in meat with added rosemary compared with meat without rosemary, as reflected in redness (a*) values, hue angles, and visual scores. Of the 4 rosemary preparations tested, the oil-soluble, most concentrated preparation (HT-O) was most effective in maintaining meat quality compared with the other 3 types tested.

Effect of ethanol rinse, Lactobacillus fermentum inoculation, and modified atmosphere on ground chicken meat quality.

Ground chicken breast meat was prepared using combinations of the following treatments: ethanol rinse before grinding, inoculation with Lactobacillus fermentum after grinding, and modified atmosphere packaging in either 90% O(2) and 10% CO(2) or 90% N(2) and 10% CO(2). Control treatments included water rinse and noninoculation with L. fermentum. Packaged meat was refrigerated and sampled for various shelf-life quality indices on d 0, 3, and 6. The inoculation with L. fermentum had little or no effect on ground meat shelf life. The ethanol-rinsed meat had lower off-odor scores and lower microbial growth compared to nonethanol rinsed meat. The high-N(2) atmosphere maintained meat color better than the high-O(2) packaging, but there was no effect on microbial growth. The combination of ethanol rinsing and high-N(2) packaging extended ground chicken quality compared with meat rinsed in water and packaged in high O(2).

Effect of dry honey on the shelf life of packaged turkey slices.

The development of off-flavors from oxidation reactions in cooked turkey products is a common problem and results in a less desirable, rancid flavor. Various strategies have been evaluated to minimize this off-flavor development, including vacuum and modified atmosphere packaging, feeding antioxidants to animals, and use of antioxidants in the final product. A natural protein-sugar reaction called the Maillard reaction produces a brown pigment, flavors, and antioxidants. This research tested the addition of honey to turkey breast meat before processing to retard production of oxidation products related to off-flavor. Three levels (0, 5, 15%) of dry honey were mixed with raw turkey breast meat pieces, then the mixture was stuffed into casing and cooked. The cooking process facilitated the Maillard reaction and the development of an antioxidative effect. The cooked chubs were then cooled, sliced, and vacuum-packaged as individual slices. The slices were refrigerated and tested for color, flavor, oxidative rancidity, and microbial growth over 11 wk. Sensory panelists detected increased sweetness and no negative flavor impact on acceptability for turkey with added honey. The addition of honey enhanced the oxidative stability of the meat, as indicated by lower TBA values, hexanal content, and oxidative stability index. Honey did impart a slightly darker color with lower lightness values but had no effect of redness and yellowness values.

Growth depth effects of bacteria in ground turkey meat patties subjected to high carbon dioxide or high oxygen atmospheres.

Modified atmosphere packaging (MAP) is used to extend the shelf life of ground meats by altering the gas atmosphere surrounding the meat. This study evaluated how deep MAP bactericidal effects penetrate into a ground meat patty. Patties made from freshly ground turkey breasts were subjected to 2 MAP treatments of high CO(2) (97%) or high O(2) (80% O(2), 20% CO(2)). Total plate and lactic acid bacterial counts were determined for 3 patty depths (top, middle, bottom). Meat surface color and the package gas headspace composition were also measured. All analyses were performed on 0, 3, 6, 9, and 12 d. Changes in gas headspace and meat surface color were also measured at 0, 3, 6, 9, and 12 d. High CO(2) atmosphere maintained a better meat surface color than high O(2) atmosphere over the whole storage period. Overall counts were lower (P < or = 0.05) in a high-CO(2) atmosphere compared with a high-O(2) modified atmosphere. Patties stored under a high-CO(2) atmosphere displayed slower bacterial growth in the top layer compared with the middle and bottom layers. Total plate count did not differ (P > or = 0.05) in layers for patties pack-aged in a high-O(2) atmosphere Lactic acid bacterial counts increased in the high-O(2) modified atmosphere by d 9 and 12 of storage; no increase was observed in CO(2)-packaged patties. Thus, high-CO(2) MAP slowed the growth of total bacteria as well as lactic acid bacteria. Also, there was slower growth in the top meat layer exposed to CO(2) compared with interior layers.

Effects of packaging atmospheres on shelf-life quality of ground ostrich meat.

Fresh ground ostrich meat was packaged under high oxygen (O2), high nitrogen (N2), vacuum (VAC) and ambient air (AIR) atmospheres, stored at 4±1°C and displayed under 1700±100lux of fluorescent lighting for 9 days. The meat was evaluated for changes in typical shelf-life characteristics consisting of pH, color properties (CIE L(∗), a(∗), b(∗), and total color difference, ΔE), oxidative changes (thiobarbituric acid value and hexanal content) and bacterial counts (total viable cell, coliform, lactic acid bacteria, Enterobacteriaceae, Pseudomonas spp.) Initial meat pH was 6.16 and declined slightly during storage. TBA values and hexanal content were highest in O2 and lowest (P⩽0.05) in VAC and N2 atmospheres. Surface lightness (L(∗)) and redness (a(∗)) were highest in O2 packaging initially, decreasing (P⩽0.05) by day 9. ΔE of the ground ostrich increased during storage in only O(2) and AIR packaging. All packaging methods had generally similar effects on microbial outgrowth. Total aerobic bacteria attained >10(6) CFU/g meat between day 3 and day 6. Ground ostrich meat was below saleable quality in less than 6 days based on all of the meat attributes. For O2 packaging however, quality based on lipid oxidation and color properties indicated a shelf-life of less than 3 days. Oxidation is likely the limiting factor for shelf-life of ground ostrich meat.

Thickness and compositional effects on surface heating rate of bologna during in-package pasteurization.

The surface heating rate (gamma) and final surface temperature (alpha) during in-package pasteurization were determined for different thickness levels of 2 types of bologna having different (13 and 18%) fat contents. Three thicknesses (4, 12, and 20 mm), corresponding to 1, 3, and 5 slices of bologna, were vacuum-packaged separately in a clear polymer pouch after placing a thermocouple on the surface. Refrigerated samples were immersed in a water bath set to 1 of 4 predetermined temperatures (60, 70, 80, and 90 degrees C), and time and temperature data were recorded for 10 min. Surface heating rate was fastest in the thinnest (4 mm) and slowest in the thickest (20 mm) samples for all 4 temperatures. Surface heating rate was slower in bologna with the higher fat content compared with the lower fat bologna. Final surface temperature attained after 3 min was lower with increased thickness levels for all temperatures. Thus, meat sample thickness and fat content significantly affect surface heating rate and final surface temperature during in-package pasteurization of bologna.

D and z-values for Listeria monocytogenes and Salmonella typhimurium in packaged low-fat ready-to-eat turkey bologna subjected to a surface pasteurization treatment.

The D-values of Listeria monocytogenes and Salmonella Typhimurium at various surface pasteurization temperatures were determined for low-fat turkey bologna. Four cm2 meat squares were sterilized by irradiation prior to inoculation with 0.1 mL of a 10(8) cfu/mL culture, aseptically packaged in a linear low-density polyethylene pouch, and vacuum-sealed. Thermal treatments were administered by submerging packages in a heated water bath maintained at various set temperatures. At an 85 degrees C water bath temperature, no L. monocytogenes cells were detected (<10(2)) after 10 s of exposure, whereas at 61 degrees C cells viable were detected (>10(2)) up to 10 min of heating. No S. Typhimurium cells (<10(2)) were detected after 10 s at 70 degrees C, but cells survived up to 7 min at 60 degrees C. The D-values for L. monocytogenes at 61 and 65 degrees C were 124 and 16.2 s, respectively; whereas S. Typhimurium D-values were 278 s at 57 and 81 s at 60 degrees C. Z-values were 4.44 and 5.56 degrees C, respectively, for L. monocytogenes and S. Typhimurium. This study demonstrated that significant reductions in bacterial populations and complete inactivation of S. Typhimurium and L. monocytogenes cells can be achieved using an in-package thermal pasteurization process.

Effect of lauric acid and nisin-impregnated soy-based films on the growth of Listeria monocytogenes on turkey bologna.

Research in development of antimicrobial packaging applications for further processed meats has become more common with recent outbreaks of contamination of these products. In this present study, lauric acid (8%, wt/wt) and 2.5% pure nisin (4%, wt/wt) were incorporated singly and together into thermally compacted soy films. Biocide-impregnated films were compared to control films containing no biocide for inhibition of Listeria monocytogenes in liquid medium and on turkey bologna surface. L. monocytogenes suspended in 1% peptone medium exposed to control films increased from 106 to 10(9) after 48 h exposure at 22 C. Films with nisin alone suppressed cell numbers 1 log cfu/mL after 2 h but cell numbers increased to 10(8) after 24 and 48 h at 22 C. Films containing lauric acid and nisin completely eliminated detectable cells from a 10(6) culture after 8 h of exposure to the liquid medium (22 C). Refrigerated bologna exposed to control films increased by 0.5 log from 10(6) after 21 d at 4 C. Nisin films reduced cell numbers on turkey bologna from 10(6) to 10(5) after 21 d, as did films containing nisin and lauric acid. Films with lauric acid alone reduced L. monocytogenes culture from 10(6) to < 102 after 48 h and by 1 log on turkey bologna after 21 d.

The effect of shell egg pasteurization on the protein quality of albumen.

The effect of a low-temperature, extended-time, in-shell pasteurization process on the protein quality of egg albumen was evaluated. Ten dozen fresh chicken eggs were pasteurized in a hot-air oven at 55 C for 180 min. The eggs were refrigerated and broken out for analysis on Days 0, 7, 14, 28, 42, and 56 following pasteurization. There were no significant differences in total or soluble protein over the experimental period for the pasteurized or unpasteurized albumen. Mean protein content was 80.6 +/- 0.5% for the pasteurized albumen and 80.9 +/- 0.5% for the unpasteurized albumen. In vitro digestibility, as measured by the AOAC method, was 82.4 +/- 0.7% for the pasteurized albumen and 81.7 +/- 0.6% for the unpasteurized albumen. There were no significant differences over the experimental period in the digestibility of the samples. Free amino acids and discriminant-computed protein efficiency ratio (DC-PER) also did not differ between the pasteurized and unpasteurized albumens or over the experimental period. The in-shell pasteurization process used had no effect on the protein quality of albumen.

Antimicrobial effects of corn zein films impregnated with nisin, lauric acid, and EDTA.

Bacterial growth during food transport and storage is a problem that may be addressed with packaging materials that release antimicrobials during food contact. In a series of five experiments, EDTA, lauric acid (LA), nisin, and combinations of the three antimicrobial agents were incorporated into a corn zein film and exposed to broth cultures of Listeria monocytogenes and Salmonella Enteritidis for 48 h (sampled at 2, 4, 8, 12, 24, and 48 h). Four experiments used starting cultures of 10(8) CFU/ml in separate experiments tested against each bacterium; the fifth experiment examined the inhibitory effect of selected antimicrobial agents on Salmonella Enteritidis with an initial inoculum of 10(4) CFU/ml. L. monocytogenes cell numbers decreased by greater than 4 logs after 48 h of exposure to films containing LA and nisin alone. No cells were detected for L. monocytogenes (8-log reduction) after 24-h exposure to any film combination that included LA. Of all film agent combinations tested, none had greater than a 1-log reduction of Salmonella Enteritidis when a 10(8)-CFU/ml broth culture was used. When a 10(4) CFU/ml of Salmonella Enteritidis initial inoculum was used, the films with EDTA and LA and EDTA, LA, and nisin were bacteriostatic. However, there was a 5-log increase in cells exposed to control within 24 h. The results demonstrate bacteriocidal and bacteriostatic activity of films containing antimicrobial agents.

Antioxidative effect of maillard reaction products formed from honey at different reaction times.

Maillard reaction products (MRP) were synthesized from honey-lysine by refluxing with water for 4, 8, 12, 16, and 20 h. The MRP from each reaction time were added to and reacted with a linoleic acid buffered emulsion at 37 degrees C. The MRP from each of the five reaction times were added to the linoleic acid emulsion (LAE) at 1%, 5%, 10%, 15%, and 20% (v/v). The antioxidative effect of MRP on the LAE was determined spectrophotometrically at 234 nm. The MRP pH and brown pigment formation (450 nm) was measured. Absorbance at 450 nm increased from 0.6 to 1.6 between the 4 h and 20 h MRP treatments, respectively. The pH of the MRP decreased from 4 h to 20 h reaction solutions, ranging from 4.2 to 3.65. The antioxidative effect increased at each reaction time increment. Within each reaction time, the antioxidative effect was maximized between 10% and 15% addition levels.

Effect of dry honey on oxidation in turkey breast meat.

The effect of adding dry honey to turkey breast meat on oxidative stability was measured using TBA, volatile headspace, and oxidative stability index. Ground turkey breast meat was mixed with different concentrations of dry honey (0, 1, 5, 10, 15, and 20%) then cooked in polyethylene bags to 72 C. Oxidative stability measurements were taken for raw meat and cooked meat and for cooked meat after 48 h of storage at 4 C. The proximate composition of the raw meat was 73.9% moisture, 23.2% protein, and 1.3% fat. Gas headspace analysis determined hexanal to be the most abundant volatile compound. Hexanal content decreased as the amount of added honey increased in both freshly cooked meat and in meat stored for 48 h at 4 C. The TBA values also decreased with increasing levels of added honey in the freshly cooked and 48-h-stored meats. The percentage inhibition of oxidation for the 5, 10, 15, and 20% samples increased from 50 to 76% for the freshly cooked meat and from 34 to 88% for the 48-h-stored meat. The oxidative stability index increased with increasing concentrations of honey from 0.28 h (control) to 7.73 h (20% honey). Addition of up to 15% honey inhibited the development of oxidative compounds in cooked turkey meat, with little further inhibition observed compared to 20% honey.

Packaging effects on shell egg breakage rates during simulated transportation.

Shell eggs were packaged in either expanded polystyrene (EPS) foam or molded paper pulp (MPP) one dozen cartons, then were bulk packaged in either polypropylene crates or corrugated boxes. The packages were then subjected to a well-defined computer-simulated vibration test on an electrohydraulic test machine. The percentage and the location on the egg (side, top, bottom) of breakage was determined in the secondary (corrugated box or polypropylene crate) and primary (EPS or MPP carton) package after 15, 75, and 180 min. For each of three trials, 60 dozen Grade A large eggs were randomly assigned to each primary package and cross-stacked in a secondary container that contained three cartons in a row and a total of five layers. When cartons were packed in 15-dozen corrugated boxes, no significant difference was found in total eggshell damage rates between the MPP carton and the EPS carton. However, when eggs were packed in 15-dozen plastic crates, the MPP cartons caused significantly less eggshell damage than the EPS cartons. The EPS cartons packed in corrugated boxes had the lowest breakage (4.63%), whereas the EPS foam cartons packed in plastic crates had the highest breakage (12.59%). When the effect of secondary packaging and vibration time were not considered, no significant difference was found between MPP and EPS cartons. In addition, when the effect of primary packaging was not taken into account, the corrugated boxes had significantly lower breakage rates than the plastic crates. Nearly 55% of the breakage occurred in the bottom section of the eggshell as compared to the side and top. When the test periods were compared, the EPS cartons packed in plastic crates had the highest breakage (16.28%) at 180 min.

Incorporation of food-grade antimicrobial compounds into biodegradable packaging films.

Lysozyme and nisin are both antimicrobial proteins effective against gram-positive bacteria. The use of these antimicrobials in combination with chelating agents displays increased effectiveness against gram-negative bacteria. Packaging films with lysozyme or nisin incorporated into the film structure were tested separately for inhibition against Lactobacillus plantarum. Both lysozyme and nisin were used in combination with EDTA in films and were evaluated for inhibition against Escherichia coli. Two packaging film-forming methods were used to incorporate lysozyme or nisin into biodegradable protein films to determine if antimicrobial properties could be induced in the film. Heat-press and casting methods were used to produce films made from soy protein and corn zein. Circular samples were cut from the finished films, which were then placed on a bacterial lawn, incubated, and measured for any zones of inhibition. Both cast and heat-press films with added lysozyme or nisin formed excellent films and exhibited inhibition of bacterial growth. The lysozyme and nisin retained their bacteriocidal properties throughout both the heat-press and cast film-forming processes. The cast films exhibited larger inhibitory zones, as compared to the heat-press films, when the same levels of lysozyme or nisin were incorporated. L. plantarum was inhibited by films containing nisin or lysozyme. The addition of EDTA increased the inhibitory effect of films against E. coli.

Protein-to-film adhesion as examined by amino analysis of protein binding to three different packaging films.

A weak protein solution extracted from chicken breast meat was exposed to three types of packaging materials. The crude myofibrillar protein solution (12.0 mg protein/mL buffer) was suspended in a 0.6M NaCl/NaPO4 buffer, then placed in bags made from either polyethylene (nonbinding film), a nylon blend (binding film), or Surlyn (binding film). Two separate experiments were conducted to determine the effects of exposure time at a constant temperature and varying endpoint exposure temperatures on the amount of bound protein by amino acid analysis. Bound amino acids were quantified and grouped by class based on functional side group. It was theorized that differences in the amount of bound amino acid class was linked to the mechanism by which the meat-to-film binding occurs. The protein solution was sealed in bags and held in a water bath for 5 s, 20 min, 40 min, and 60 min at 25.8 C for the timed experiment and heated from 25.8 C to 40, 55, 70, and 80 C for the temperature experiment. Protein adhesion occurred due to exposure of the solution to all films at 25.8 C. Greater protein adhesion was found in the two binding films than in the nonbinding film after 60 min of exposure. Heating the protein solution increased adhesion for the Surlyn film and showed a clear delineation in the degree of binding between the film types. Surlyn bound the most protein, followed by the nylon blend and then polyethylene. Bound protein increased in the Surlyn film with heating to 80 C, whereas the polyethylene did not show an increase in the amount of bound protein. Increases in binding observed between 55 and 80 C for Surlyn may be associated with transitional and conformational changes in muscle proteins that affect the adhesion of meat to the film surface.