Biomedical subjects

J A Cason

Publications and source records attributed to J A Cason.

At least 37 records · Page 2Linked to original sources

PubMed2002

Variation in numbers of bacteria on paired chicken carcass halves.

Bacterial counts from paired broiler carcass halves were examined for relationships between numbers and kinds of bacteria that might indicate fecal contamination. Broiler carcasses removed from a commercial processing plant just before chilling were split aseptically along the midline, and each side was rinsed in 400 mL of phosphate buffered saline for 1 min with either mechanical or hand shaking. Both halves of six carcasses were rinsed on four different days for a total of 24 carcasses sampled with each shaking method. Aerobic bacteria, coliforms, Escherichia coli, and Campylobacter jejuni were enumerated and summed to obtain whole carcass counts. There were no significant (P < 0.05) differences in numbers of bacteria recovered by the two rinse methods. In left-right comparisons, only E. coli was significantly different (P = 0.04), with the right side having higher counts (least-square means of 1.09 vs. 0.97). For aerobic plate count (APC), coliforms, E. coli, and Campylobacter, correlations between paired left and right side counts were between 0.78 and 0.86. The correlation between whole carcass counts and absolute left-right differences was significant for APC (0.43), but was not significant for coliforms, E. coli, and Campylobacter, so higher whole carcass counts were not associated with higher counts on one side of the carcass. Correlations between different bacteria on whole carcasses were significant for E. coli-APC (0.39), E. coli-coliforms (0.67), and APC-coliforms (0.71), but other combinations had non-significant correlations. The correlation was not significant between E. coli and Campylobacter, a relatively fragile organism whose presence can be interpreted to indicate fairly recent fecal contamination. There were no indications that high E. coli counts on inspection-passed, prechill carcasses indicated recent fecal contamination.

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↗

PubMed2002

Enumeration and identification of yeasts associated with commercial poultry processing and spoilage of refrigerated broiler carcasses.

Yeasts associated with broiler carcasses taken from various stages of commercial poultry processing operations and broiler carcasses stored at refrigerated temperatures were enumerated and identified. Whole carcass rinses were performed to recover yeasts from carcasses taken from a processing facility and processed carcasses stored at 4 degrees C for up to 14 days. Yeasts in the carcass rinsates were enumerated on acidified potato dextrose agar and identified with the MIDI Sherlock Microbial Identification System. Dendrograms of fatty acid profiles of yeast were prepared to determine the degree of relatedness of the yeast isolates. Findings indicated that as the carcasses are moved through the processing line, significant decreases in the number of yeasts associated with broiler carcasses usually occur, and the composition of the yeast flora of the carcasses is altered. Significant (P < 0.05) increases in the yeast population of the carcasses generally occur during storage at 4 degrees C, however. Furthermore, it was determined that the same strain of yeast may be recovered from different carcasses at different points in the processing line and that the same strain of yeast may be isolated from carcasses processed on different days in the same processing facility.

Animals↗

PubMed2001

Unheated water in the first tank of a three-tank broiler scalder.

Scalding with unheated water in the first tank of a simulated three-tank scalder was tested to determine whether carcass bacteria, efficiency of feather removal, and cooked breast meat tenderness are affected as compared with carcasses scalded at the same temperature (57 C) in all tanks. This experiment was performed on 3 d using 6-wk-old broilers. On each day, eight birds per treatment were processed. During the first 40-s scalding period, one carcass was placed in approximately 24 C water. The other carcass was placed simultaneously in a scalder unit containing approximately 2,050 L of water at 57 C. Carcasses were then held out of the water for 15 s, after which both were placed for 40 s in opposite ends of the scalder containing water at 57 C. After the second scalding period, both carcasses were again removed from the water for 15 s, followed by another 40 s in the 57 C water. Total scald time was 2 min for each treatment. After picking, carcasses were rinsed with 200 mL of sterile 0.1% peptone water for 1 min. Aerobic bacteria and Escherichia coli were enumerated and incidence of salmonella was determined by standard methods. After rinsing, carcasses were eviscerated by hand and chilled for 30 min in ice slush. All carcasses were scored for the presence of feathers, and the appearance and condition of the skin were noted. Four hours postmortem, breast fillets were removed from carcasses and chilled overnight at 2 C. The next morning, breast fillets were cooked to an internal endpoint temperature of 75 to 80 C. Warner-Bratzler shear values were measured to determine tenderness. No differences were found in numbers of aerobic bacteria and E. coli, incidence of salmonellae, tenderness of cooked breast meat, or number of feathers left on carcasses.

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

Salmonella penetration of egg shells and proliferation in broiler hatching eggs--a review.

The presence of salmonellae in fertile broiler hatching eggs has been clearly identified as a critical control point in the salmonellae contamination of broiler chickens. This paper reviews the published research studies on a) the penetration and proliferation of salmonellae in hatching eggs, b) the consequences of this contamination on the contamination of the final product, and c) the egg's defenses against invading salmonellae. A better understanding of the material in this review paper will assist poultry researchers and the poultry industry in continuing to make progress in reducing and eliminating salmonellae from fertile hatching eggs, hatcheries, and breeder flocks.

Animals↗

PubMed2000

Campylobacter recovery from external and internal organs of commercial broiler carcass prior to scalding.

Campylobacter is a human pathogen commonly found on live broilers and processed carcasses. To plan effective intervention strategies, it would be helpful to know which Campylobacter populations are associated with the external and internal organs of broilers. Six carcasses were collected after exiting the bleed tunnel at a commercial broiler plant on each of three visits (n = 18). Carcasses were placed individually into sterile plastic bags, sealed, and covered with ice for transport to the laboratory. Five locations were sampled aseptically from each carcass: breast feathers (hand picked from the sternal tracts); breast skin, including the sternal tracts; crop; ceca; and colon. Samples included adhering contamination or lumen contents and were covered with phosphate-buffered saline and blended. Serial dilutions were made for examination of Campylobacter, coliform, Escherichia coli, and total aerobic bacterial populations. Average sample weights (grams) were as follows: feathers, 1.5; skin, 6.5; crop, 5.1; ceca, 7.8; and colon, 3.1. Campylobacter populations (mean log10 colony-forming units per gram of sample) found were feathers, 5.4; skin, 3.8; crop, 4.7; ceca, 7.3; and colon, 7.2. Coliform/E. coli populations observed were feathers, 6.4/6.0; skin, 5.3/4.9; crop, 4.3/3.7; ceca, 6.6/6.2; and colon, 5.8/5.3. Total aerobic bacterial populations found were feathers, 7.9; skin, 7.1; crop, 5.8; ceca, 6.8; and colon, 6.4. On a per gram basis, ceca and colon are the internal organs that if ruptured could cause the highest number of Campylobacter to be leaked onto the carcass. The crop also contained more Campylobacter per gram than did the skin, and if compromised may increase the numbers on the surface of the carcass. However, even with no contamination from an internal organ, a substantial population of Campylobacter is already resident on broiler skin as the carcass enters the early stages of processing.

Abattoirs↗

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

Coliform, Escherichia coli, and salmonellae concentrations in a multiple-tank, counterflow poultry scalder.

Scald water samples from a commercial broiler processing plant were tested for coliforms, Escherichia coli, and salmonellae to evaluate the numbers of suspended bacteria in a multiple-tank, counterflow scalder. Water samples were taken from each of three tanks on 8 different days after 6-week-old broilers had been processed for 8 h. Coliforms and E. coli were counted using Petrifilm, and the most probable number (MPN) of salmonellae was determined both in water samples and in rinses of defeathered carcasses that were removed from the processing line immediately after taking the water samples. Mean coliform concentrations in tanks 1, 2, and 3 (the last tank that carcasses pass through before being defeathered) were 3.4, 2.0, and 1.2 log10(CFU/ml), respectively. E. coli concentrations followed the same pattern with means of 3.2, 1.5, and 0.8 in tanks 1, 2, and 3, respectively, with significant differences (P < 0.02) in the concentrations of both coliforms and E. coli between the tanks. Sixteen of 24 scald-water samples were positive for salmonellae with a geometric mean of 10.9 MPN/100 ml in the positive samples. Salmonellae were isolated from seven of eight water samples from both tanks 1 and 2, but in only two of eight water samples from tank 3, the last tank that carcasses pass through. It appears that most bacteria removed from carcasses during scalding are washed off during the early part of scalding.

Animals↗

PubMed1999

Aerobic bacteria and solids in a three-tank, two-pass, counterflow scalder.

Scald water and whole carcass rinse samples were collected on 9 different d in a commercial broiler processing plant operating adjacent lines that processed birds from the same flock simultaneously. A conventional, single-tank, two-pass scalder was installed on one line and the other line had a three-tank, two-pass, counterflow scalder in which water mixed across the two lines of carcasses within each tank. Water samples from the turn around point in each tank were analyzed for aerobic bacteria and suspended solids. At the same time that water samples were taken, six carcasses were removed from the processing line immediately after feather removal and rinsed in 100 mL of phosphate-buffered saline; recovered rinse solution was analyzed for aerobic bacteria using a most probable number procedure. Estimated numbers of aerobic bacteria were significantly reduced in the third tank of the counterflow scalder compared to the second tank, or compared to the single tank of the conventional scalder. Despite the differences in aerobic bacteria between scald tanks, numbers of aerobic bacteria in carcass rinses were not affected by scalder design. Organic and total solids were significantly reduced in the third tank of the counterflow scalder compared to the first and second tanks, and in the third tank of the counterflow scalder compared to the conventional scalder. Solids in the third (final) tank of the counterflow scalder were reduced by about 70% compared to the conventional scalder.

Animals↗

PubMed1999

Mixing of dye in a model scald tank.

A model scald tank was constructed to study the mixing pattern of water in a poultry scalding system. Tank dimensions were approximately 6 m long by 10.5 cm wide with a water depth of 18 cm. Water was vigorously agitated with compressed air delivered through a 1.9-cm polyvinyl chloride pipe on the bottom of the tank. Food coloring was added to the tank at a single point, and water samples were taken at distances of 0, 0.5, 1.0, 1.5, and 2.5 m every 30 s for 10 min, with 0 or 10 L/min water flow through the tank. Dye concentration was determined spectrophotometrically. A chain drive was then installed above the tank with aluminum paddles (area about 25% of tank cross-sectional area) attached to the chain every 15.2 cm to simulate the movement of carcasses through the water at 140 carcasses per minute. Food coloring was added to the tank, and water samples were taken every 15 s for 2.5 min, with 0 or 13.5 L/min water flow through the tank. A computer program based on perfect mixing of water in small slices or cells within the tank was adjusted until predicted dye movement matched sampling data, with correlations of 0.91 or better at all sampling points. For scalder designs with uniform mixing of water, the computer model can predict mixing patterns, including counterflow conditions in a single tank, well enough to yield realistic residence time patterns for bacteria suspended in scald water.

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

Effect of Salmonella in young chicks on competitive exclusion treatment.

The potential of Salmonella contamination in hatching cabinets to 1) generate seeder chicks and 2) interfere with the efficacy of competitive exclusion (CE) treatments was investigated in six experiments. Hatchery-generated seeder: chicks were produced by hatching in the same hatcher with inoculated eggs (immersed in a 1.0 x 10(5) cfu/mL suspension of Salmonella typhimurium or inoculated with 10(5) to 10(6) cells on the air cell membrane). Salmonella spread through the hatching cabinet to chicks hatching from uninoculated eggs in adjacent trays. In two experiments, Salmonella was isolated from 31 and 100% of the chick rinses after the birds were held in groups for 3 d in isolation units. When these hatchery-generated seeder chicks were stocked in floor pens at a 1:10 ratio with uncontaminated contact chicks, the pen environment became contaminated to the extent that greater than 50% of the contact chicks became contaminated. In two experiments with only one to three inoculated eggs per 200 egg hatching cabinet, 98% of uninoculated chicks were intestinally colonized with Salmonella after the birds were held 1 wk in isolation cabinets. This hatchery-acquired Salmonella substantially reduced the effectiveness of subsequent CE treatments to prevent Salmonella colonization of the young chicks. These studies demonstrate that control of Salmonella in hatching cabinets is critically important for control of Salmonella in broilers.

Animals↗

PubMed1997

Feather retention force in broilers ante-, peri-, and post-mortem as influenced by carcass orientation, angle of extraction, and slaughter method.

Stunning and slaughter trials were conducted to evaluate the influence of carcass orientation (inverted or supine), angle of feather extraction (parallel or perpendicular to the carcass surface), and slaughter method (exsanguination without or with spinal cord transection) on feather retention force (FRF) in commercial broilers sampled ante-, peri-, and post-mortem. The pectoral, sternal, and femoral feather tracts were sampled before and after stunning contralaterally, with a maximum indicating force gauge, from broilers suspended on a shackle (inverted) or laying on a table (supine). For all trials and sample periods FRF was consistently greater in the femoral area (547 to 679 g) than in the pectoral area (273 to 391 g), with the sternal feather tract requiring the least force at 246 to 343 g. Feathers extracted parallel to the carcass resulted in consistently greater FRF (9 to 29%) than feathers extracted at a perpendicular angle, at all sample periods. Broilers suspended on shackles ante- and peri-mortem had higher FRF values (5 to 30%) than those restrained in shackles in a supine position on a table. Other parameters resulted in minor and inconsistent alterations in FRF. Electrical stunning, when not followed by bleeding, resulted in small reductions in FRF (up to 7%). Bleeding after stunning without or with spinal cord transection resulted in variable peri-mortem FRF changes (+7 to -11% and +11 to -11%, respectively). Only in the pectoral feather tract was there a significant increase (5 to 6%) in FRF as broilers went from the ante- to peri-mortem state. At 2 and 6 min after stunning and initiation of exsanguination, post-mortem FRF was unaffected by carcass orientation for the pectoral and femoral tracts.

Abattoirs↗

PubMed1997

Feather retention force in broilers ante-, peri-, and post-mortem as influenced by electrical and carbon dioxide stunning.

Stunning and slaughter trials were conducted to evaluate the influence of stunning method (electrical 50 V alternating current, CO2 gas: 0 to 40% for 90 s or 40 to 60% for 30 s) on feather retention force (FRF) in commercial broilers. Feathers from the pectoral, sternal, and femoral feather tracts were sampled with a force gauge before stunning (ante-mortem) and contralaterally either after stunning (peri-mortem from 0.5 to 4 min) or after stunning and bleeding (post-mortem from 2 to 6 min). Prior to stunning, ante-mortem FRF values varied among assigned stunning methods only for the pectoral (7%) feather tract. After stunning, peri-mortem FRF values were higher only for the sternal tract (11% for 40 to 60% CO2 for 30 s); whereas after stunning and bleeding, post-mortem FRF values were lower than ante- or peri-mortem only for the sternal tract (10% lower for 40 to 60% CO2 for 30 s). Peri- and post-mortem FRF values did not differ among stunning methods for the pectoral and femoral feather tracts. Small changes in FRF values occurred from ante-mortem to peri-mortem (-1 to +12%), and from ante-mortem to post-mortem (-2 to +8%) across stunning methods. A significant increase was determined for only the pectoral tract (7%) from ante- to peri-mortem across stunning methods. Electrically stunned broilers that were not bled gained weight in excess of the 36 feathers removed (0.16%), apparently due to body surface water pickup during the brine-stunning process, whereas CO2-stunned broilers lost weight due to excretion of cloacal contents (-0.31 to -0.98%). The change in body weight among stunning methods was significant (P < 0.0233). Peri- and post-mortem FRF, in addition to bleed-out body weight loss, were not substantially influenced by electrical or CO2 stunning methods, and, therefore, carcass defeathering efficiency may not differ after scalding.

Animals↗

PubMed1997

Effect of cloacal plugging on microbial recovery from partially processed broilers.

Experiments were performed to test the contribution of bacteria contained in the intestinal tract of broilers at the beginning of processing to counts on the exterior of modified New York-dressed carcasses. Thirty-two birds were processed for each of seven replications. Within each replication, batches of four birds were electrocuted, scalded, and picked, with batches alternating between treatment and control groups. Treated birds were cloacally plugged with rayon fiber tampons prior to electrocution to prevent escape of intestinal contents during scalding and picking. Control birds were processed in the same manner, except that cloacal plugs were inserted immediately after defeathering to reduce escape of intestinal contents during sampling. Gram-negative enteric bacteria and Campylobacter spp. were enumerated on carcasses by whole carcass rinse procedure and in cecal contents. Counts were converted to log10 and subjected to analysis of variance. Cecal levels of Gram-negative enterics were significantly higher for plugged birds, but there was not a significant difference between levels of cecal Campylobacter spp. between treatment groups. Plugging before electrocution resulted in significantly lower levels (2.5 vs 3.0 log10 cfu/mL) of Campylobacter spp. and Gram-negative enteric bacteria (3.0 vs 3.4 log10 cfu/mL) in carcass rinses of treatment birds than in those of controls. All carcasses were positive for Gram-negative enterics. Cloacal plugging resulted in significantly lower incidence of Campylobacter spp. carcass contamination as determined by chi-square. Intestinal carriage of both campylobacters and Gram-negative enteric bacteria appears to influence the microbial quality of the carcass during processing.

Analysis of Variance↗

PubMed1997

Effect of muscle opposition during rigor on development of broiler breast meat tenderness.

Two experiments were conducted to determine the effect of mutual opposition of breast muscles during rigor development on ultimate tenderness of the cooked meat. In each experiment, 32 broilers were conventionally processed. Immediately after evisceration, the supracoracoideus tendon was cut at the humeral insertion on one wing (treatment) and the opposite wing was sham-operated with the tendon exposed but not cut (control). The tendon of insertion for the Pectoralis minor muscle was cut to prevent the opposition of breast muscles during rigor, while avoiding confounding effects caused by making cuts on the muscles, as would occur during typical deboning. Cutting the tendon significantly (P < 0.05) increased Warner-Bratzler shear values after cooking for both the Pectoralis major and P. minor. Deboning at 2 h post-mortem resulted in shear values for the P. major of 7.22 kg for controls and 9.08 kg for treated carcasses; P. minor shear values were 2.98 kg for controls and 4.04 kg for treated carcasses. Deboning at 24 h post-mortem produced P. major shear values of 4.68 kg for controls and 5.68 kg for treated carcasses. On whole carcasses, breast muscle opposition during rigor contributes to the tenderness of the cooked meat.

Animals↗

PubMed1997

Relationship between aerobic bacteria, salmonellae and Campylobacter on broiler carcasses.

Broiler carcasses were removed from commercial processing lines immediately after defeathering, before chilling, and after chilling to determine whether any relationship exists between aerobic bacteria and the human enteropathogens salmonellae and Campylobacter. In two experiments, a whole carcass rinse procedure was used to sample 30 carcasses after defeathering, 90 carcasses before chilling, and 90 carcasses after chilling, for a total of 210 different carcasses. Aerobic bacteria and Campylobacter spp. were enumerated and the incidence of salmonellae was determined. Salmonellae and Campylobacter incidences were 20 and 94%, respectively, for all carcasses sampled. After picking, neither salmonellae-positive nor Campylobacter-positive carcasses had mean aerobic most probable number (MPN) values that were different from carcasses negative for those organisms. Immediately before chilling, aerobic and Campylobacter counts were 7.12 and 5.33 log10 cfu per carcass, respectively. Immersion chilling reduced aerobic counts by approximately 1.8 log and Campylobacter by 1.5 log, with no change in salmonellae-positive carcasses. There was no difference in aerobic or Campylobacter counts between carcasses that were positive or negative for salmonellae at any of the sampling locations, nor was any correlation found between levels of aerobic organisms and Campylobacter. Carcasses with aerobic counts above the mean or more than one standard deviation above the mean also failed to show any correlation. Discriminant analysis indicated error rates as high as 50% when numbers of aerobic bacteria were used to predict incidence of salmonellae or Campylobacter on individual carcasses. Aerobic bacteria are not suitable as index organisms for salmonellae or Campylobacter on broiler carcasses.

Animals↗