Storage and packaging effects on sensory and color characteristics of ground beef

Effects of irradiation (2 kGy) of ground beef patties from trimmings stored aerobically for 0 or 6 days on lean color, odor, and sensory attributes were investigated. Beef trimings were coarse ground and split into 2 groups. Group one was fine ground, pattied, and packaged immediately; group-two was stored 6 days then fine ground, pattied, and packaged. Irradiated beef patties had greater (P<0.05) off-odors, and off-flavors, lower (P<0.05) CIE L^*, a^* and b^* and saturation indexes values (P<0.05) after four days of storage at 0±1 °C. Irradiation of patties produced from trimmings aged an extra 6 days resulted in increased (P<0.05) saturation indexes and b^* values, but not off-odors when compared to non-aged and irradiated patties. Thus, the production of irradiated beef patties should utilize beef trimmings with the shortest postmortem aging time and a dose of less than 2 kGy to minimize discoloration and off-odors.     

The influence of season on quality characteristics of hot-boned beef m. longissimus thoracis

Samples of m. longissimus thoracis (LT) muscle were randomly collected from 70 Omani beef cattle 1 h after slaughter between August 2001 and July 2002 in the Muscat Municipality central slaughterhouse to investigate the effect of seasonal parameters on meat quality during the hot and cool seasons of Oman. The collection period (12 months) was divided into two seasons according to ambient temperatures and relative humidity and termed: Cool Season (November–March with average temperature of 21.2±1.40 °C and 57.9±1.61% relative humidity) and Hot Season (April–October with average temperature of 34.3±1.67 °C and 48.8±7.57% relative humidity). The season had a significant effect on meat quality characteristics of the LT muscle. Muscles collected during the hot season had significantly (P<0.001) higher ultimate pH values (6.24) with significantly (P<0.001) lower Warner–Bratzler (WB) shear force values (10.12) than those collected during the cool season (5.54 and 15.58). In these hot-boned samples, there was a linear relationship between ultimate pH and WB shear values. Cooking loss was significantly (P<0.001) higher for cool season samples (26.01%) than from hot season samples (19.75%). Beef from the hot season group had significantly (P<0.001) darker meat than that of the cold season group, based on L* (31.45 vs 35.58), a* (18.53 vs 23.19) and b* (4.16 vs 6.40) colour measurements. There was a linear relationship between ultimate pH and cooking loss, L*, a* and b*. These results indicated that heat stress (>30 °C) lead to physiological stress in beef cattle, which in turn increased muscle ultimate pH and influenced related meat quality characteristics.     

Colour of normal and high pH beef heated to different temperatures as related to oxygenation

The effects of oxygenation and thermal treatment (internal temperature, T_i: 45, 60, 75°C) on the colour and some colour related physical and biochemical properties of beef longissimus dorsi (LD) muscle, both normal (pH_u5.6) and DFD (pH_u>6.6), were studied. The colour components (L^*, a^*, b^* values) for the raw and heated LD, both before and after oxygenation, were instrumentally and sensorily evaluated. The colour of raw and heated (60°C) DFD beef before and after oxygenation differed significantly from the normal meat and contained more native muscle pigment (TMP). pH also influenced the depth of the oxygenated layer, specific activity of cytochrome c oxidase (SACCO) and the amount of oxygen consumed. An increase in internal temperature was usually accompanied by a lower SACCO and a significant decrease of TMP, as well as a change of all colour parameters. Oxygenation of the raw and heated slices (except at 75°C) of both types of meat led to higher L^*, a^* and b^* values.     

High voltage electrical stimulation enhances muscle tenderness, increases aging response, and improves muscle color from cabrito carcasses

Our study examined high and low voltage electrical stimulation and postmortem storage as strategies to improve tenderness and lean color in cabrito carcasses. Boer cross (n=60) kids were assigned to either high (550 V), low (20 V), or no electrical stimulation treatments. No differences in muscle temperature were observed between treatments at any time measured. Muscle pH declined fastest in high voltage treated carcasses. High voltage electrical stimulation slightly increased (P<0.05) b^* and a^* in the M. gluteus medius and tended to increase L^* and b^* (P=0.06 and 0.11, respectively) values in the M. longissimus thoracis. Electrical stimulation had no effect on myofibril fragmentation at 1-, 3-, or 14-d postmortem or sarcomere length. High voltage electrical stimulation increased (P<0.05) tenderness at 1- and 3-d postmortem, but not at 14-d postmortem. Aging for 3 d did not affect tenderness regardless of stimulation treatment, but aging time for 14 d improved (P<0.05) tenderness. These data indicate that high voltage electrical stimulation and 14 d aging were effective in improving the tenderness of meat from cabrito carcasses.     

The effects of electrical stunning and percussive captive bolt stunning on meat quality of cattle processed by Turkish slaughter procedures

The effects of electrical and percussive captive bolt stunning both on initial and up to 14 days post mortem meat quality of Friesian young bulls were studied. The first group (NS; n=10) were slaughtered without stunning under Turkish slaughter procedure (these animals were slaughtered under conditions acceptable to the appropriate ethics committee) in a modern abattoir. In the second group (ES; n=10) animals were electrically stunned. In the third group (PS; n=10) animals were stunned with percussive captive bolt. Meat quality was assessed by examining muscle glycogen concentration, pH and WHC. Also cooking loss, texture parameters and consumer sensory properties were assessed at 24 h, 4, 7 and 14 days post mortem. Meat colour as L^*, a^*, b^*, C^*, h^* values were evaluated at 0, 48 h, 3, 5, 7, 9 and 14 days post mortem. Pre-slaughter handling affected muscle glycogen concentration (P<0.05). Animals in electrical and percussive captive bolt stunned groups had higher muscle glycogen concentrations compared to animals in the non-stunned group (P<0.05). Although pre-slaughter handling did not affect significantly pH_{24 h} and WHC, differences were significant for cooking loss, colour coordinates and texture parameters at some storage times. For all sensory attributes (odour, flavour, tenderness and overall acceptability) at all ageing periods (24 h, 4, 7 and 14 days) the percussive stunned (PS) group was significantly superior to the non-stunned (NS) group. The electrically-stunned (ES) group also tended to be superior to the NS group although not all differences were statistically significant. These results indicate that percussive captive bolt stunning of cattle improved meat quality compared with cattle electrically stunned using head only tongs and those non stunned under approved Turkish slaughter procedure.     

Effect of different stunning systems on meat quality of light lamb

The present study was proposed to compare the effect that different types of stunning (TS) had on the quality of refrigerated meat from light lambs of the Spanish Manchega breed at 24 h and 7 days post-mortem. Lambs were electrically stunned (ESL; n = 10), using CO₂ (GSL; n = 10) or slaughtered without previous stunning (USL; n = 10). Measurements on meat quality were carried out by evaluating pH, colour coordinates (L^*, a^*, b^*), water holding capacity (WHC), cooking loss (CL), shear force (SF) and drip loss (DL). At 24 h post-mortem, no significant differences were found in any of the variables studied. However, at 7 days post-mortem, meat quality was affected by the different TS: pH, CL and DL were lower (P < 0.001) in the USL group and GSL obtained the lowest a^* (redness) and b^* (yellowness) values (P < 0.01) than in the other groups. Ageing of meat affected SF in the ESL group (P < 0.01), although there were no significant differences due to treatments at any of the ageing times.     

Color evaluation of carbon monoxide treated porcine blood

The stability of liquid porcine blood, treated with carbon monoxide (CO) at different pH values (7.40, 6.70, and 6.00) up to its complete saturation, was studied. Lowering the pH from 7.40 to 6.70 resulted in a decrease in the amount of CO necessary to obtain 100% carboxyhemoglobin. Further pH lowering to 6.00 did not result in additional reduction in the amount of gas. During 4 days of refrigerated storage CO treated liquid blood maintained, at every pH, a more stable and attractive red color than fresh blood, which was a result of an increase (P<0.05) of a^* (redness) and b^* (yellowness) values and no variation (P>0.05) on L^* (lightness) value. Hue (h^*) and chroma (C^*) decreased in the untreated blood but not in the CO-treated blood. The results indicate that blood saturation with CO yields a product having greater potential for use in meat products without compromising its visual appearance.     

Use of digital images to estimate CIE color coordinates of beef

The objective of this study was to evaluate the use of digital images (DI) to estimate CIE L^*a^*b^*, hue angle and chroma of beef, as compared to a colorimeter (CM). Loin samples from 21 steers finished with high-grain diets were displayed under retail-simulated conditions. Color readings were obtained from 63 cores covering the full spectrum of discoloration in beef. CIE L^*, a^*, and b^* were measured with a surface-reflectance CM. Red, green and blue (RGB) values were obtained from DI and sequentially transformed to XYZ and CIE L^*a^*b^* color space. Hue angle and chroma were calculated from a^* and b^* values. Regressions of CM on DI for a^*, hue angle and chroma had R² values of 0.93 and above. Average color difference () between the predicted and the actual CM L^*, a^*, and b^* values for 13 samples that were not included in the regressions was 1.57, below reported thresholds of detection for 50% of observers. Color readings from DI could be used to accurately predict color coordinates measured by CM, especially a^*, hue angle and chroma. Use of digital imaging could become a practical tool to detect changes in beef color and other muscle foods.     

Physicochemical and sensory properties of chicken nuggets with washed mechanically deboned chicken meat: Research note

The effects of different proportions (0%, 10%, 20%, 30%, 40%) of washed mechanically deboned chicken meat (WM) as a substitute for hand deboned chicken meat, on the physicochemical and sensory characteristics of chicken nuggets were evaluated. The addition of WM increased fat content, but it was only significant (P < 0.05) when 40% of WM was added, whereas the protein content was significantly (P < 0.05) reduced as from 20%. Significant differences (P < 0.05) were found in L^*, a^* and b^* values with different proportions of WM, however, these differences were evidently not discerned as shown by the no significant differences (P > 0.05) in ΔE^* color scores. The addition of WM did not affect (P > 0.05) sensory attributes of chicken nuggets. From a technical viewpoint, up to 40% WM could be incorporated into nugget formulation instead of hand deboned chicken meat without affecting sensory attributes of the product. Minor changes in composition were observed but they were probably not detrimental to the product.     

Effect of stunning conditions on occurence of PSE defects in hams of rn+/RN(-) pigs

Pigs of the same genetic type at the RN and HAL loci, i.e. rn⁺RN⁻/NN were reared in similar conditions of feeding and housing. They were slaughtered in two abattoirs (referred to as A1 and A2) using a mixture of air (30%) and CO₂ (70%), at a rate of 300 pigs per hour per slaughterline. One hundred and thirty-two pigs from 11 farms were slaughtered in A1 using a corusinga restrainer and 127 pigs from 5 farms were slaughtered in A2 with the backloading technique. pH at 40 min, 2.5 h and 24 h after slaughter and colour (L*, a*, b*) at 24 h after slaughter were measured in the semimembranosus muscle. Meat quality of the ham was scored as follows: 1, no PSE-zone; 2, doubtful; 3, PSE-zones in the semimembranosus and sometimes on the internal flexor muscles; 4, PSE-zones in all the flexor muscles. The muscle pH value was higher in A2 than in A1 at 40 min post mortem (P<0.01), but not at 2.5 and 24 h. L* (P<0.001) and b* (P<0.05) were higher in A1 than in A2. There was a remarkable difference in meat quality scores, with 50% of the hams scoring 3 or 4 in A1, vs 13% in A2. Lairage time before slaughter affected (P<0.01) the pH value at 2.5 h (5.69 vs 5.93). The values of pH1 and pH2.5 decreased with increasing the meat quality score. The values of L* and b* increased markedly with the score. The results of the present study indicate that the method of bringing the slaughter pigs to the stunning device affects the frequency and importance of PSE meat in the ham. The automated driving of groups of animals to the stunning machine combined with the backloading of a nacelle, compared to a traditional system driving pigs in single file using electrical goads and a restrainer was beneficial with respect to both meat quality and animal welfare.     

Factors associated with surface iridescence in fresh beef

The objective of this study was to investigate factors associated with surface iridescence in fresh beef. Eight muscles were evaluated for occurrence of surface iridescence: Biceps femoris (BF), Gluteus medius (GM), Longissimus lumborum (LD), Psoas major (PM), Rectus femoris (RF), Semimembranosus (SM), Semitendinosus (ST), and Tensor fasciae latae (TF). Incidence of surface iridescence was 91% for ST, 34% for SM, 27% for LD, 20% for GM, 12% for RF, 9% for BF, 8% for TF, and 6% for PM (P<0.05). Factors associated with surface iridescence in the ST were further examined because iridescence was observed to a much higher degree in the ST as compared with other muscles evaluated. Greater ST surface iridescence was associated with larger ribeye areas, more youthful lean maturity scores, higher L^*, a^* and b^* colorimeter values, lower ultimate pH values, and faster cooking (P<0.05).     

Effect of genetic origin, diet and weaning weight on carcass composition, muscle physicochemical and histochemical traits in the rabbit

Fifty rabbits originating from the crossing of one dam strain with three sire strains, Hy+, INRA 9077 and INRA 3889, were studied. The adult body weights of the sire strains were 5·1, 4·1 and 3·1 kg, respectively. After weaning, the Hy+ and the INRA 9077 rabbits were fed either an H (11·99 MJ DE kg DM⁻¹) or L diet (9·67 MJ DE kg DM⁻¹). The INRA 3889 rabbits were fed only the H diet. In each of these five blocks, two weaning weights were studied and the rabbits were slaughtered when the average body weight of each block reached 2·5 kg. Slaughter yield, carcass fatness and hindleg meat to bone ratio were determined. Muscular tissue was described using (1) physicochemical criteria (ultimate pH, L^*a^*b^* colour) of the biceps femoris (BFE), tensor fasciae latae (TFL) and semimembranosus accessorius (SMA) muscles and (2) histochemical characteristics of the longissimus lumborum muscle (LL) through computerised image analysis (fibre type composition, cross-sectional area). At slaughter, the rabbits of INRA 3889 sire origin, which had the highest degree of maturity (72%), gave the best slaughter yield (p<0·01), the heaviest reference carcass weight (p<0·01), and highest LL proportion (p<0·01), hindleg meat to bone ratio (p<0·05) and fatness (p<0·01); their LL muscle showed the lowest percentage of βR fibres, while the cross-sectional area of their muscular fibres was the highest (p<0·05). When all sire × diet combinations were put together, the heavier the weaning weight, the lower the daily gain (p<0·01) and the lightness (L*) of thigh muscles (p<0·05). The lower the DE content of the diet, the lower the growth rate, the slaughter yield, the reference carcass weight (p<0·01) and the cross-sectional area of all types of muscle fibres of the rabbits of both Hy+ and INRA 9077 sire origin.     

Effects of transportation at high ambient temperatures on physiological responses, carcass and meat quality characteristics of three breeds of Omani goats

The experiment was designed to determine the effects of short road transportation in an open truck during the hot season on live weight shrink, physiological responses, carcass, and meat quality characteristics in three breeds of Omani goats. Forty-two male goats (12 months of age) representing equally three breeds of Omani goats (Batina, Dhofari, and Jabal Akhdar) were divided into two groups: 2 h transportation stress (TS) or not transported (NT). The NT group remained unstressed in holding pens with feed and water provided ad libitum prior to slaughter, while the TS group was transported on the day of slaughter 100 km in an open truck. The average temperature during transportation was 37 °C. All animals were blood-sampled before loading and prior to slaughter via jugular venipuncture. Animals were weighed just before loading onto a truck and after transport to assess shrinkage. Muscle shear force, sarcomere length, pH, expressed juice, color, and cooking loss were measured on samples from Mm longissimus dorsi (LD), biceps femoris (BF), and semitendinosus (ST) muscles collected at 24 h postmortem at 1–3 °C. Live weight shrinkage losses were between 1.07 and 1.28 kg. The TS goats had higher plasma cortisol (P < 0.01), adrenaline, nor-adrenaline, and dopamine concentrations (P < 0.05) than NS goats. Blood serum from Batina goats had significantly (P < 0.05) higher cortisol, adrenaline and dopamine and nor-adrenaline concentrations than those from Jabal Akdhar goats. Transportation stress had a significant (P < 0.05) effect on meat quality characteristics of the LD, BF, and ST muscles. Meat from TS goats had significantly higher ultimate pH, expressed juice, cooking loss percentage, shear force, but significantly lower sarcomere length, L^*, a^*, and b^* values. LD muscles of Batina goats had significantly higher ultimate pH values and lower L^* values than Dhofari and Jabal Akdhar goats. These results indicated that subjecting goats to the 2-hour road transportation with high ambient temperatures can generate major physiological and muscle metabolism responses.     

Effect of pH at time of salting on the functional properties of pre-rigor beef

The functional properties of thawed pre-rigor beef that had been minced and salted or not salted when its pH value reached 6.8, 6.6, 6.4, 6.2 and 6.0, then immediately frozen, were determined. The mince samples were used to manufacture a finely comminuted sausage batter. Presalting before frozen storage resulted in higher (p < 0.05) thawed mince pH, and batter cook yield and shear strain, and lower (p < 0.05) mince salt soluble proteins, thaw drip and Hunter L^* and b^* values and batter shear stress than unsalted controls. The pre-rigor pH at time of salting/mincing affected (p < 0.05) thaw drip (unsalted mince only), Hunter L^* and b^* values and shear stress. Shear stress tended to increase (p < 0.01) and Hunter L^* (p < 0.05) and b^* (p < 0.01) values tended to decrease with fall in pre-rigor salting pH. No interaction (p > 0.05) between salting and pre-rigor pH at time of salting was observed.     

Meat quality characteristics of springbok (Antidorcas marsupialis). 1: Physical meat attributes as influenced by age, gender and production region

Springbok is the most extensively cropped game species in South Africa. The effects of age (adult, sub-adult, lamb), gender and production region on the physical attributes (pH₂₄, cooking and drip loss, Warner Bratzler shear force and colour) were determined using samples of the M. longissimus dorsi (LD) muscles of 166 springbok. Stressed animals had a higher (P < 0.05) pH₂₄ (6.3 ± 0.07), as observed in the meat originating from the Caledon region. This meat had lower (P < 0.05) cooking loss (27.2 ± 0.62%) and drip loss (1.8 ± 0.08%) values in comparison to meat originating from the other regions. Inverse correlations were noted between pH₂₄ and drip loss (r = −0.26, P < 0.01) and cooking loss (r = −0.42, P < 0.001). Shear force values (kg/1.27 cm diameter) correlated positively (r = 0.25, P < 0.01) with pH₂₄. Age-related effects on tenderness were small in comparison with pH₂₄ effects. CIELab colorimetric values were typical of game meat and venison (L^* < 40, high a^* and low b^* values). It was noted that pH₂₄ correlated negatively (r = −0.51, P < 0.001) and positively (r = 0.33, P < 0.001) with the hue-angle and the chroma value of colour, respectively. Springbok originating from Caledon had a significantly (P < 0.05) higher a^* value, indicating meat to be more red with higher colour saturation.     

Effects of age on composition and quality of muscle Longissimus thoracis of the Omani Arabian camel (Camelus dromedaries)

The aim of this study was to determine the effects of age on chemical composition and quality characteristics of the Arabian one-humped camel’s meat. Samples of longissimus thoracis (between the 10th and the 13th rib of the left side) were randomly collected from 21 Omani intact male camels of three different age groups: group 1 (1–3 years), group 2 (3–5 years) and group 3 (6–8 years). Samples were chilled (1–3 °C) for 48 h. Moisture, crude protein, fat and ash were determined on freeze dried ground muscle. Mineral contents were determined using an Inductively coupled plasma emission spectrometer (ICP). Meat quality including ultimate muscle pH, Warner–Bratzler shear force, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss percent, and colour L^*, a^*, b^* were measured using standard methods.

The moisture, protein, fat and ash ranged from 64.4% to 76.7%; 18.6% to 25.0%, 1.1% to 10.5% and 1.0% to 1.4% on dry matter basis, respectively. The Ca, Mg, Na, K, P, Cad, Cr, Ni, Pb, Co, Mo, Be and V ranged from, 9.2 to 46.6, 24.7 to 57.3, 104.7 to 257.0, 471.4 to 1053.0, 249.9 to 584.0, 0.005 to 0.024, 0.020 to 0.410, 0.016 to 0.187, 0.010 to 0.299, 0.010 to 0.018, 0.050 to 0.470, 0.005 to 0.030 and 0.013 to 0.141 mg/100 g on dry matter basis, respectively. The percentage of protein decreased and that of fat increased with increasing camel age. The ultimate pH, shear force, sarcomere length, fragmentation index, expressed juice, cooking loss, lightness (L^*), redness (a^*) and yellowness (b^*) ranged from 5.46 to 6.64, 4.25 to 17.82, 0.96 to 2.50, 55.91 to 94.81,19.50 to 33.63, 13.18 to 29.88, 27.86 to 43.21, 10.46 to 22.81, and 4.63 to 10.11, respectively. Muscles of younger camels (group 1) had significantly (P < 0.05) lower shear force value, ultimate pH and higher sarcomere length, fragmentation index, expressed juice, cooking loss, and lightness color (L^*) by 48%, 3.4%, 43%, 25%, 28%, 14%, and 16% than those collected from older camels (group 3), respectively. Values of middle age camels (group 2) camels were in-between. This study confirmed that camel meat is healthy and nutritious as it contains low fat as well as being a good source of minerals. Age is an important factor in determining meat quality and composition.     

Effect of transport time and ageing on aspects of beef quality

Forty-eight bulls were transported by road in groups of eight for approximately 30 min, 3 or 6 h in two replicates. After slaughter, steaks from the longissimus dorsi thoracis of all transported animals were analysed in terms of pH, water-holding capacity, myoglobin concentration, texture at 7 and 14 days of ageing (compression and Warner-Bratzler analyses) and colour of the same surface of meat cut at 24 h post-mortem and allowed to bloom for 24 h and 7 d (L^*a^*b^*, chroma and hue). The myofibrillar resistance of the meat from animals transported 30 min was significantly greater at 20% compression (P<0.05). The maximum load and a^*b^* and chroma were all lower for meat aged 14 days.     

Lipid and protein oxidation, release of iron from heme molecule and colour deterioration during refrigerated storage of liver pâté

In the present work, lipid and protein oxidation, increase of non-heme iron (NHI) content and colour changes occurring during refrigerated storage (90 days/4 °C) of liver pâtés from Iberian and white pigs were studied. Iberian pigs were reared outdoors and fed on natural resources (grass, acorns) while white pigs were intensively reared and fed on a mixed diet. Lipid and protein oxidation were, respectively, measured by determining TBA reactive substances (TBARS) and protein carbonyl groups. Pâtés from Iberian pigs had better oxidative stability at all stages of storage, having lower amounts of TBARS and carbonyls compared to those from white pigs (p<0.05). NHI increased during refrigerated storage of liver pâtés, with those from white pigs having a higher amount of NHI at all stages of storage (p<0.05). During refrigerated storage, L^*-values tended to increase while the evolution of a^* and b^* depended on the group and did not seem to be related to the oxidative processes.     

Nonenzymic browning during storage of white hard grape pekmez (Zile pekmezi)

Effects of storage period on hydroxymethylfurfural, pH and colour were studied in white hard grape pekmez (Zile pekmezi), a Turkish traditional product. Pekmez samples were stored at 20 °C for 8 months. Analysis of variance revealed significant differences in hydroxymethylfurfural, pH, L, a and b values (P<0.01) based on storage time.     

Dietary tea reduces the iron content of beef

We hypothesized that the lightness of Japanese beef was related to the concentration of heme iron. In Experiment 1, six Japanese Black heifers were allotted randomly to one of three treatment groups: a basal concentrate ration (40% flaked corn) or the same diet and either 2 kg/d wheat bran or 0.5 kg/d green tea. After feeding the diets for 174 d, the cattle were slaughtered and the M. longissimus thoracis, M. semimembranosus, and M. gluteus medius were sampled for meat color, iron, and lipid content. The iron content of the M. semimembranosus from the tea-fed cattle was lower than in M. semimembranosus from the control cattle, and a* (redness) and √(a^*2+b^*2) (saturation) values were lower in M. semimembranosus from bran- and tea-fed cattle than in control cattle. Treatment main effects (across muscles) indicated that inclusion of tea in the diet increased intramuscular lipid and reduced the muscle iron content. There was a significant negative correlation (r²=0.79) between muscle iron content and L^* value (lightness). For Experiment 2, the effect of beef breed type on meat color and iron content of M. longissimus thoracis was investigated using stored meat samples from six breeds from a previous fattening experiment done under a high nutritional plane. Muscle iron content was significantly lower in Japanese Black cattle than in Japanese Black × Holstein or Japanese Black × Japanese Black/Holstein. There was no relationship between muscle iron content and intramuscular lipid content (r²=0.001). In Experiment 3, samples of M. longissimus dorsi were obtained from 17 Wagyu crossbred and 3 Angus crossbred cattle fed a corn concentrate diet in the USA for 148 d. Iron content of the M. longissimus thoracis from Japanese Black and Japanese Brown × Holstein cattle fattened in Japan was significantly less than the iron content of M. longissimus dorsi from cattle raised in the USA. Overall, the data indicate that it is possible to lower muscle iron, and lighten muscle color, by feeding green tea to Japanese cattle; also, there may be a genetic basis for the lower iron, and lighter color, of beef produced in Japan.