Biomedical subjects

J A Dickens

Publications and source records attributed to J A Dickens.

At least 19 recordsLinked to original sources

PubMed2004

Effects of applying Safe2O poultry wash to broiler wings on shelf life, Listeria monocytogenes, Pseudomonads, Staphylococcus species, and psychrotrophic bacteria levels after three, seven, and ten days of storage.

Bacterial contamination of raw processed poultry continues to be of concern to consumers as well as regulatory and health officials. For many years wings were considered a low-value product; therefore, shelf life of wings was not a major concern. Due to changes in consumer attitudes and increases in the fast-food market, wings are now a valuable commodity. Because wings have a shorter shelf life than most other raw poultry products, acceptable intervention to decrease the population of associated spoilage organisms and human enteropathogens are needed. Safe2O Poultry Wash was evaluated as a postchill treatment to reduce microbial contamination and increase shelf life. Ninety-six carcasses were obtained from a local processor prior to final wash. On arrival at the research facility all carcasses were inoculated with 1 mL of a culture with 10(3) cfu/mL Listeria monocytogenes. After a 30-min attachment time, carcasses were subjected to a 4-s in-out final wash, hung for 3 min, and chilled in ice-water for 45 min. After the chilling, wings were removed by hand with a knife, pooled together, and subjected to a hand spray (4 mL/wing) with deionized water or Safe2O Poultry Wash. Two wings were then placed in each of 96 ziplock type storage bags, and wings were held at 5 +/- 1 degrees C for 3, 7, 10, and 14 d. On the day of sample, weep was decanted, and 100 mL of Butterfield's phosphate buffer was added to each bag. Three sets of wings were shaken by hand for 1 min, and total aerobes, Pseudomonads, Staphylococcus sp., psychrotrophic bacteria, and L. monocytogenes in the rinsates were enumerated. By using 7 log10 recovery of total aerobes from rinsates as a spoilage baseline, all wings were spoiled by d 10, but the wings treated with water were approaching spoilage counts on d 7, (log10 6.8), whereas only log10 5.5 bacteria were recovered from the wings sprayed with Safe2O Poultry Wash. Fewer Pseudomonads, Staphylcoccus sp., L. monocytogenes, and psychrotrophic bacteria were recovered from wings treated with Safe2O Poultry Wash and stored for 10 d. Log10 counts for the organisms were Pseudomonas sp., 8.2 and 6.9; Staphylcoccus sp., 5.5 and 4.9; L. monocytogenes, 5.2 and 4.6; and psychrotrophs, 8.2 and 6.9 for the water and Safe2O Poultry Wash treatments, respectively. Use of the Safe2O Poultry Wash as a postchill treatment on wings could increase the shelf life of wings by up to 3 d.

Animals↗

PubMed2003

Effect of broiler age, feed withdrawal, and transportation on levels of coliforms, Campylobacter, Escherichia coli and Salmonella on carcasses before and after immersion chilling.

A study was conducted to determine effects of bird age at slaughter, feed withdrawal, and transportation on levels of coliforms, Campylobacter, Escherichia coli, and Salmonella on carcasses before and after immersion chilling. Broilers were processed at 42, 49, and 56 d of age after a 12-h feed withdrawal period or a 0-h feed withdrawal period (full fed). At each age, broilers were processed from two commercial farms previously identified as Campylobacter positive. One week before slaughter, broilers were gavaged with nalidixic acid-resistant Salmonella. During bleeding, cotton plugs were inserted into the cloaca of each carcass. Whole-carcass rinses (WCR) were performed before and after immersion chilling with 20 ppm sodium hypochlorite, and rinses were analyzed for coliforms, Campylobacter, E. coli and Salmonella. Log10 counts for coliforms, Campylobacter, and E. coli were (P < 0.05) affected by bird age at slaughter. Feed withdrawal (FW) affected only Campylobacter on carcasses of older broilers (56 d of age). Chilling with sodium hypochlorite resulted in log10 reductions of 1.2, 1.3, 1.4, and 0.5 for coliforms, Campylobacter, E. coli, and Salmonella, respectively. Under the conditions of this experiment, it appears that contamination on the exterior of birds entering the processing facility is critical to carcass bacterial counts. Moreover, carcass bacterial counts did not vary when microbial counts of broilers were comparable. FW may increase prechill carcass counts for E. coli and Campylobacter, but it appears to have no effect on postchill carcass counts when sodium hypochlorite is used in the chilling operation.

Aging↗

PubMed2003

Filling and emptying of the alimentary tract of meal-fed broiler breeder hens.

For evaluation of the filling and emptying of the alimentary tract, broiler breeder hens were cooped and processed over a 2-d period. Hens were fed at 0600 h on d 1 and after access to feed for 0, 2, 4, and 6 h were placed into coops. Half of the hens from each pen were either immediately processed or were held in coops over-night and processed the following morning, d 2. The alimentary tract was excised from the carcass and then separated and weighed in three segments: the crop, proventriculus and gizzard, and intestines. Hens processed on d 1, after access to feed for only 2 h, had attained maximum intestine weight (176 g), but not until after access to feed for 6 h were peak crop weight (95 g) and peak weight for the proventriculus and gizzard (78 g) attained. Hens processed on d 2 did not differ in crop (12 to 14 g) or intestine (140 to 162 g) weight, but proventriculus and gizzard weights were significantly lower for hens not fed on d 1 prior to cooping (54 g) compared with hens fed on d 1 and cooped after 2, 4, or 6 h (62 to 63 g). However, hens processed on d 2 had proventriculus and gizzard weights that were the same as for those hens processed on d 1 and cooped at 0 h (63 g). Clearance of ingesta from the crop, proventriculus and gizzard, and intestines readily occurred while hens were held overnight without access to water.

Animal Feed↗

PubMed2002

Tenderization of hot-boned broiler breast meat by clamping during chilling.

Hot-boned broiler breast fillets were tightly clamped between rigid aluminum plates during chilling to determine whether tenderness is increased if breast fillets are not allowed to shorten during rigor. In two experiments, 6-wk-old broilers were processed in a pilot plant. Approximately 5 min after evisceration, the breast fillets (pectoralis major) were deboned, and each fillet was subjected to one of two treatments while chilling for 2 h in ice slush. Fillets were placed in perforated plastic bags (hot-boned control) or clamped between rigid aluminum plates that compressed the meat to a uniform thickness of 7.2 mm during chilling. In Experiment 2, chilling time in ice slush was 1 h, and a third treatment was added to make an incomplete block design in which one breast half was left intact on the carcass and was deboned immediately after chilling. All breast fillets were sealed in plastic bags after the chilling period, held overnight at 4 C, and then cooked at 85 C for 30 min in a steam kettle. In Experiment 1, clamping for 2 h reduced Warner-Bratzler shear values of hot-boned fillets from 11.4 to 2.7 kg. In Experiment 2, shear values for the treatments were 13.0, 9.2, and 5.1 kg for the hot-boned, cold-boned, and hot-boned clamped treatments, respectively, with significantly lower shear values for the clamped fillets. Clamped fillets were significantly thinner than the control fillets in both experiments. Cooked yield as a percentage of postchill weight was significantly higher for the clamped compared to the hot-boned control pieces, 81.1 versus 77.3%, with cold-boned pieces being intermediate and not different from the other treatments. Shear values were reduced, and cooked yield was increased by clamping hot-boned fillets during chilling.

Animals↗

PubMed2002

Microbiological consequences of skin removal prior to evisceration of broiler carcasses.

The objective of this project was to determine if removal of skin prior to evisceration lowers the number of bacteria that can be recovered by whole carcass rinse or sponge sampling. Four experiments were conducted, two with each type of sampling (rinse or sponge). New York dressed carcasses obtained from a commercial broiler processing plant were aseptically skinned or left with skin intact. The carcasses were then aseptically eviscerated by hand. Carcasses were rinsed in 100 mL sterile water or sampled by moist sponge. When sampled by rinse, significantly fewer Campylobacter and total aerobic bacteria were recovered from carcasses that had been skinned prior to evisceration. When sampled by sponge, significantly fewer Campylobacter, Escherichia coli, coliform and total aerobic bacteria were recovered from the outer surface of carcasses without skin. No differences were noted for bacterial counts recovered from internal surfaces by sponge sampling. Similar trends were observed when carcasses were subjected to an inside and outside washing step after evisceration. Removal of skin and washing the carcass led to significantly less Campylobacter being recovered by whole carcass rinse compared to carcasses that were washed with the skin on. When sampled by sponge, incidence of Campylobacter and level of total aerobic bacterial counts were lower on the outer surface of skinned and washed carcasses than on washed carcasses with intact skin. Like the unwashed carcasses, no differences were noted for bacterial counts recovered from internal surfaces by sponge sampling. Although not commercially practical, it is possible to lower the level of Campylobacter on the outside of broiler carcasses by removal of the skin prior to evisceration.

Animals↗

PubMed2001

Broiler carcass contamination with Campylobacter from feces during defeathering.

Three sets of experiments were conducted to explore the increase in recovery of Campylobacter from broiler carcasses after defeathering. In the first set of experiments, live broilers obtained from a commercial processor were transported to a pilot plant, and breast skin was sampled by a sponge wipe method before and after defeathering. One of 120 broiler breast skin samples was positive for Campylobacter before defeathering, and 95 of 120 were positive after defeathering. In the second set of experiments, Campylobacter-free flocks were identified, subjected to feed withdrawal, and transported to the pilot plant. Carcasses were intracloacally inoculated with Campylobacter (10(7) CFU) just prior to entering the scald tank. Breast skin sponge samples were negative for Campylobacter before carcasses entered the picker (0 of 120 samples). After defeathering, 69 of 120 samples were positive for Campylobacter, with an average of log10 2.7 CFU per sample (approximately 30 cm2). The third set of experiments was conducted using Campylobacter-positive broilers obtained at a commercial processing plant and transported live to the pilot plant. Just prior to scalding, the cloacae were plugged with tampons and sutured shut on half of the carcasses. Plugged carcasses were scalded, and breast skin samples taken before and after defeathering were compared with those collected from control broilers from the same flock. Prior to defeathering, 1 of 120 breast skin sponge samples were positive for the control carcasses, and 0 of 120 were positive for the plugged carcasses. After passing through the picker, 120 of 120 control carcasses had positive breast skin sponge samples, with an average of log10 4.2 CFU per sample (approximately 30 cm2). Only 13 of 120 plugged carcasses had detectable numbers of Campylobacter on the breast skin sponge, with an average of log10 2.5 CFU per sample. These data indicate that an increase in the recovery of Campylobacter after defeathering can be related to the escape of contaminated feces from the cloaca during defeathering.

Animals↗

PubMed2000

Effects of hot water application after defeathering on the levels of Campylobacter, coliform bacteria, and Escherichia coli on broiler carcasses.

Scalding has been found to lower the levels of Campylobacter on broiler carcasses. However, the numbers recovered from whole-carcass rinse samples increase following defeathering. This study was undertaken to examine the effect of a second scald applied after defeathering on microbial levels recovered from carcass rinses. Four treatments were evaluated: 1) immersion at 60 C for 28 s 30 min after defeathering, 2) immersion at 60 C for 28 s immediately after defeathering, 3) spray at 73 C for 20 s 30 min after defeathering, and 4) spray at 71 C for 20 s immediately after defeathering. As reported earlier, a significant increase in Campylobacter counts per mL whole carcass rinse was noted after carcasses were defeathered. However, when applied 30 min after defeathering, neither the immersion nor the spray second scald treatments lowered the Campylobacter counts. Likewise, neither treatment had any affect on Escherichia coli or coliform bacteria counts, even though total counts were slightly reduced by the treatments. When the second scald treatment immediately followed defeathering, the same trends were observed. Campylobacter counts after the second scald remained at the postpick levels, as did counts for E. coli and coliform bacteria, but total plate counts were slightly reduced. Overall, it would appear that a postscald treatment gentle enough not to alter the carcass appearance or meat quality would not effectively lower Campylobacter, E. coli, or coliform bacteria counts.

Animals↗

PubMed2000

Influence of flooring type during transport and holding on bacteria recovery from broiler carcass rinses before and after defeathering.

Four trials were conducted to determine whether conventional solid or elevated wire mesh flooring, during transport and holding of broilers prior to slaughter, influenced the number of bacteria recovered from feathered and defeathered carcasses. After 4 h off feed, 7-wk-old broilers were placed at commercial density into a modified commercial transport dump-coop on either fiberglass sheeting or 2.54x2.54 cm wire mesh flooring that allowed feces to fall through. Broilers were transported for 1 h and then held for 13 h under a covered shed before processing. Broilers were killed by electrocution, and the vents were plugged to prevent escape of feces. External carcass rinses were obtained twice (from the same carcass) from eight broilers per flooring treatment per trial, before scalding and defeathering and again after defeathering and removal of the head and feet. Greater numbers of total aerobes, coliforms, and Escherichia coli were recovered from feathered carcasses than from defeathered carcasses. Campylobacter count was also less for defeathered than feathered carcasses from the solid flooring treatment but did not significantly decrease following defeathering of carcasses from the wire flooring. The incidence of Campylobacter-positive carcasses was reduced following defeathering for both flooring treatments, but the percentage of Salmonellae-positive carcasses remained constant. Coliform (log10 6.20 vs. 5.63 cfu/mL of rinse) and E. coli (log10 5.93 vs. 5.36) counts in the feathered rinses were significantly higher for the solid flooring compared with wire flooring, respectively. After defeathering, the number of coliforms (log10 3.12) and E. coli (log10 2.91) recovered did not differ between flooring treatments. Aerobic plate count (log10 7.06 and 4.02), Campylobacter count (log10 2.49 and 1.80), and the incidence of Campylobacter-positive (44 and 11%) and Salmonellae-positive (52 and 50%) carcasses for feathered and defeathered rinses, respectively, did not differ between flooring treatments. These results indicate that although broilers transported and held on solid flooring had noticeably dirtier breast feathers and higher coliform and E. coli counts prior to scalding and defeathering, bacteria recovery from external carcass rinses did not differ between the solid and wire flooring treatments after defeathering.

Animals↗

PubMed2000

Efficacy of an herbal extract on the microbiological quality of broiler carcasses during a simulated chill.

Protecta II, an herbal extract on an NaCl carrier, was evaluated in a 30-min, 1 C simulated chill for its effectiveness of lowering microbial counts on broiler carcasses. Eighteen broiler carcasses were obtained from a local processing plant after final wash but before chill, placed into an insulated container, and transported to the research facility for treatment. Six plant run controls (PRC) were immediately bagged on return to the pilot plant, and a whole-carcass rinse was performed. The remaining carcasses were subjected to a 30-min chill (1 C) in tap water or a 2% solution of Protecta II, (n = 6 per treatment). After treatment, carcasses were rinsed with tap water and subjected to the whole-carcass rinse procedure. All rinse diluents were microbiologically analyzed for total aerobes, coliforms, generic Escherichia coli, and Campylobacter. Six replications were analyzed on 6 different d for a total 36 carcasses per treatment and 36 PRC. The PRC carcasses had 3.7, 2.5, 2.1, and 2.0 log10 cfu/mL for total aerobes, coliforms, generic E. coli, and Campylobacter. Water treatment significantly reduced counts (2.6, 1.4, 0.7, and 0.9 log10 cfu/mL, respectively) when compared with the PRC. Protecta II treatment significantly reduced counts (P < 0.01) even further to counts of 0.06, 0.04, 0.01, and 0.00 log10 cfu/mL for total aerobes, coliforms, Campylobacter, and E. coli, respectively. Detectable levels of the monitored organisms were 1 cell/mL (log10 0) for the E. coli, coliforms, and total counts and 10 cells/mL (log10 1) for the Campylobacter. Microbial counts for carcasses treated with Protecta II would be considered too low to be detected (<1 cell/mL).

Animals↗

PubMed1999

Subcutaneous temperature profile, skin appearance, and picking efficiency of immersion and spray scalded broiler carcasses.

To compare immersion and spray scalding temperature profiles, thermocouples were positioned beneath the skin of broiler carcasses in eight separate locations. The locations were as follows: 1 and 2) the upper left and right breast, 3 and 4) middle of the left and right thigh, 5 and 6) beneath the left and right wing, 7) the lower back above the pygostyle, and 8) the upper back between the wings. Standard immersion scalding at 52 or 56.5 C for 2 min or a prototype spray scalder at 60, 65, or 70 C for 1 min were used to monitor s.c. temperature during scalding. Immersion scalding resulted in an exponential profile with the lower temperature having less temperature deviation for the monitored locations. Among sampling locations, the spray scald temperatures were divergent among locations and the highest temperatures were recorded when thermocouples were within the spray patterns. As with the immersion scalded carcasses, lower temperatures for the spray scalding demonstrated less deviation among the monitored locations and a closer grouping of the final temperatures. The only spray scald temperature tested at which s.c. temperatures approached those of the immersion scalded carcasses was 70 C. Additional carcasses were scalded, picked, and examined for skin appearance and picking efficiency. All carcasses spray scalded for 60 s had a "cooked appearance" when evaluated. When spray scald times were reduced to 30 s, skin appearance improved, but with the exception of the 70 C trial, picking efficiency was poorer.

Animals↗

PubMed1998

Effects of age and tissue type on the calpain proteolytic system in turkey skeletal muscle.

A study was conducted to examine the effects of bird age and muscle tissue type on calpain and calpastatin activities in turkey skeletal muscle. Enzymatic activities of calpains and calpastatin were found to vary with bird age and muscle type. Breast muscle from younger birds (age 5 wk) had higher mu-calpain, m-calpain, and calpastatin activities (P < 0.05) than breast muscle from older birds (9, 13, and 17 wk of age). Thigh muscle calpain activities were not affected by bird age, but thigh calpastatin activity was found to increase with age, with muscle from 17-wk-old birds having 35% higher activity than muscle from 13-wk-old birds. When extracted from 9-wk-old turkeys, breast muscle mu-calpain activity was 30% higher than thigh muscle mu-calpain. By 13 wk of age, breast muscle mu-calpain activity was 20% less than thigh mu-calpain. Thigh muscle m-calpain and calpastatin activities were found to be significantly higher (P < 0.05) than that found in breast muscle, with some values more than double in older birds (17 wk of age).

Aging↗

PubMed1997

Effects of acetic acid and hydrogen peroxide application during defeathering on the microbiological quality of broiler carcasses prior to evisceration.

The microbiological quality and skin appearance of New York dressed broiler carcasses were determined in two separate experiments after a water control, acetic acid, or H2O2 spray during defeathering. Broilers were picked up from a local processor and transported in coops to the pilot facility. In both experiments, commercial processing parameters were followed up to the defeathering step. After feather removal, the vents of all carcasses were blocked with a cotton plug to prevent contamination of the whole carcass rinse diluent with fecal material from the lower gut. The neck and feet were removed, and the carcasses were placed in individual plastic bags in preparation for a whole carcass rinse. Results showed a statistically significant reduction (P < 0.05) in the log10 total aerobic plate counts for carcasses treated with 1% acetic acid in comparison to the water control (log10 cfu counts = 3.93 and 4.53, respectively). No differences were observed in skin appearance due to the 1% acid treatment. The addition of 0.5, 1, or 1.5% H2O2 to spray waters had no effect on microbiological quality of the carcasses when compared to the water control (4.92, 5.01, 4.91, and 4.99 log10 counts, respectively). The skin of carcasses treated with hydrogen peroxide, regardless of the concentration was bleached and bloated.

Acetic Acid↗

PubMed1995

The effects of extended chilling times with acetic acid on the temperature and microbiological quality of processed poultry carcasses.

The effects of extended chill times with and without .6% acetic acid and agitation on the microbiological quality of broiler carcasses were determined. Carcasses were chilled for either 1, 2, or 3 h using the following treatments: 1) paddle chiller without acid (C); 2) static ice slush with .6% acetic acid (S); 3) static ice slush with air agitation and .6% acetic acid (SA); and 4) a paddle type chiller with .6% acetic acid (P). Whole carcass rinse samples were taken at 1, 2, and 3 h (two per time per treatment) and evaluated for total aerobes and Enterobacteriaceae and at 1 and 2 h for Salmonella incidence. Six replications of 24 carcasses per replication were used for the standard microbiological evaluations and five runs of 24 carcasses per run were used for the determination of Salmonella incidence. Total aerobes were reduced (P < or = .05) by .34, .62, and 1.16 log10 most probable number/mL for the S, SA, and P treatments, respectively, when compared with the controls. Enterobacteriaceae counts were reduced (P < or = .05) by .50, .71, and 1.4 log10 for the S, SA, and the P treatments, respectively. Salmonella incidence, from inoculated carcasses, after 1 h were 87% for the C carcasses, 80% for the S treatment, 53% for the SA treatment, and 6.7% for the P treatment.

Acetates↗

PubMed1994

The effect of an acetic acid dip on carcass appearance, microbiological quality, and cooked breast meat texture and flavor.

In Experiment 1, broiler carcasses were subjected to a 10-min prechill treatment with and without a food grade vinegar at a concentration of .6% acetic acid. After treatment the carcasses were monitored for visual appearance and microbiological quality. Color change and skin appearance were subjectively monitored. Microbiological quality was determined using the low volume whole carcass rinse. Shear values of cooked muscle were determined using a Warner-Bratzler attachment to an Instron. In a second experiment using the same treatment protocol, treated carcasses were chilled in an ice slush for 30 min and held overnight at 2 C. The breast muscles were removed and cooked by two methods. Triangle tests to determine sensory differences due to acetic acid were conducted. The skin color of treated carcasses turned a light yellow, and the feather follicles were protruded or puckered. Total aerobic counts were not affected by any of the treatments, but Enterobacteriaceae (ENT) counts of treated carcasses were significantly lower than the counts for the water control carcasses. Log10 ENT counts ranged from 4.51 for the control to 3.80 for the carcasses treated with acetic acid. Based on sensory triangle tests using a trained panel, there were no significant differences in the samples from either cooking method.

Acetates↗

PubMed1994

The effect of acetic acid and air injection on appearance, moisture pick-up, microbiological quality, and Salmonella incidence on processed poultry carcasses.

Broiler carcasses were subjected to a 10-min prechill treatment with and without air injection and glacial acetic acid at concentrations of .3 and .6%. Some of the carcasses were inoculated with approximately 800 cells of a nalidixic acid-resistant strain of Salmonella typhimurium 1 min prior to treatment. After treatment, the carcasses were monitored for their visual appearance, moisture pick-up, and microbiological quality. Appearance was subjectively monitored for color change and resulting skin texture. Microbiological quality was determined using the low volume whole carcass rinse, and moisture pick-up was determined by weight differences. The skin color of treated carcasses was light yellow and the feather follicles were protruded or puckered. Moisture pick-up was significantly reduced by the acid treatments. Total aerobes were not affected by any of the treatments, but Enterobacteriaceae (ENT) counts of treated carcasses were significantly lower than the counts for the water control carcasses. Log10 ENT counts ranged from 5.52 for the control to 4.48 for the air injection, and to a low of 2.93 for the air injection with .6% acetic acid. Salmonella incidence of inoculated carcasses was significantly reduced by the treatments. Using .6% acetic acid with air injection resulted in the greatest reduction in Salmonella incidence (8% positive).

Abattoirs↗

PubMed1993

Effect of two stunning voltages on blood loss and objective texture of meat deboned at various post-mortem times.

Two experiments were conducted to determine the effect of different stunning voltages on the objective texture of the Pectoralis major muscles deboned at various post-mortem times. Broilers were stunned at either 50 or 200 V alternating current (VAC) for 10 s in a brine stunner. The artery and vein on one side of the neck were severed, blood collected for 90 s, and blood loss calculated as percentage of live weight. Carcasses were then processed under simulated commercial conditions. In the first experiment, the right and left Pectoralis major muscles were excised at 1 and 2 h post-mortem respectively, weighed, vacuum-sealed in plastic bags, and held overnight at 2 C. In the second experiment, the Pectoralis major muscles were excised at 4 h post-mortem and held overnight at 2 C. The muscles were then heated at 85 C for 30 min, equilibrated to room temperature, and prepared for Warner-Bratzler shear analysis. The stunning treatments did not significantly affect blood loss, which averaged 2.86 and 2.64% for 50 and 200 VAC, respectively. Birds subjected to the 50 VAC treatment had a mean shear value of 7.3 kg, which was significantly lower (P < .05) than the mean shear value of 10 kg for birds subjected to the 200 VAC treatment for muscles excised 2 h post-mortem. The use of 200 VAC for stunning could be used without any detrimental effect on the cooked meat as long as the standard deboning time of 4 h was maintained.

Animals↗

PubMed1992

The effect of air scrubbing on moisture pickup, aerobic plate counts, Enterobacteriaceae, and the incidence of salmonellae on artificially inoculated broiler carcasses.

Processed broiler carcasses were subjected to diffused air at 158.6 kPa (air scrubbing) in tap water to evaluate the potential of this treatment for improving the microbiological quality of read-to-cook poultry. Carcasses were inoculated with a marker strain of Salmonella typhimurium 5 min before treatment. The carcasses were removed after 30 min and sampled for aerobic plate counts (APC), Enterobacteriaceae (ENT) counts, for the presence of the marker organism, or for moisture pickup. The S. typhimurium were recovered from 32 of 40 control carcasses (water only), but from only 9 of 40 air-scrubbed samples. When carcasses were inoculated with fewer than 150 cells of the marker organism, air scrubbing was more effective in reducing the incidence of salmonellae (2 of 20 positive) than when levels were in excess of 150 cells (7 of 20 positive). A similar pattern was manifested with the water-rinsed carcasses rinsed without air injection (below 150, 12 of 20; above 150, 20 of 20). No significant differences were found in the APC and ENT counts. Moisture pickup was adversely affected by air scrubbing; control carcasses had a moisture pickup of 5.8%, whereas, air-scrubbed carcasses had a moisture pickup of 13.9%.

Analysis of Variance↗

PubMed1989

Effects of electrical stimulation on the post-mortem biochemical changes and texture of broiler pectoralis muscle.

A study was conducted to determine the influence of electrical stimulation (50,200, or 350 V ac) on biochemical and textural changes in broiler breast muscle. Sixty-four broilers were stunned (50 V ac) prior to kill, and all but a control group were pulse stimulated during bleeding. After processing, carcasses were held in 10-C water for 1 h, then in 2-C ice/water slush for 1 h prior to muscle removal at 2 h post-mortem (PM). Bagged samples were held at 2 C for 24 h, then cooked. The pH, R value (ratio of adenine nucleotides to inosine nucleotides), cook yield, fluids and solids lost (F&S), and objective texture were measured. In addition, 16 broilers processed in the same manner were used in producing a profile of sarcoplasmic protein/enzyme changes in the breast muscle by cation exchange fast protein-liquid chromatography at 10 min, 2, and 24 h PM. The R values and soluble protein were also determined. Stimulation at 200 and 350 V accelerated the onset of rigor noted by lower pH values at 10 min and 1 h PM, and higher R values at 2 h PM. Muscle stimulated at 350 V exhibited the lowest cook yield and highest percentage of F&S lost, suggesting both the loss of functional properties and muscle integrity due to this treatment. All control and stimulated samples exhibited shear values in excess of what would be considered tender. Hardness and chewiness values increased as stimulation voltage levels increased. Only one of the seven principal chromatographic peaks decreased in response to increased electrical stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗