Alternative slaughter procedures: on-farm slaughter and transport system for broilers.

This paper focuses on "alternative methods for initial broiler processing" and exploration of alternative processing including slaughter at the farm immediately after catching. On-farm slaughter and transport (FSaT) is envisioned as a mobile unit that stuns, slaughters, and shackles the broiler carcasses at the farm. A separate trailer-unit then transports the shackled broiler carcasses to the processing plant. Once at the processing plant carcasses are mechanically transferred into plant shackle lines and moved into processing. The hypothesis is that the FSaT approach will dramatically improve overall bird welfare and well-being by reducing live handling and eliminating live transport from the farm to the processing plant. In addition, ancillary impacts could include: improving yield efficiencies by eliminating dead on arrivals, potentially reducing water and energy consumption, reducing labor requirements at the processing plant with the elimination of live rehang, and offering an economically sustainable alternative. The FSaT approach represents a radical change from traditional processing, and its effects on poultry processing need to be evaluated. This paper presents results of experiments conducted at a commercial poultry processor to evaluate feather picking efficiency, carcass bacteriological loading, and meat quality for delayed processed carcasses.

Evaluation of mechanical cervical dislocation, captive bolt, carbon dioxide, and electrical methods for individual on-farm euthanasia of broiler breeders.

Efficacious euthanasia by applying manual cervical dislocation can be difficult on large and mature poultry. The challenge with using manual cervical dislocation is that the strength required to hold heavy poultry and swiftly apply cervical dislocation can be physically impossible for most people. Therefore, alternative methods of euthanasia are needed for mature and large poultry. Mechanical cervical dislocation using the Koechner Euthanizing Device (KED), captive bolt using the Turkey Euthanasia Device (TED), carbon dioxide (CO2), and electrical euthanasia were evaluated for use on 65-wk-old broiler breeders at flock termination. Following application of each method, physiological reflexes including the eye nictitating membrane reflex, mouth gaping, and body movement, broken skin, blood loss, kill success, time to cessation of heartbeat, and blood plasma corticosterone levels were assessed. Birds euthanized using the KED had longer response durations for eye nictitating membrane (91 s) and reflexive mouth gaping (161 s) compared to TED, CO2, and electrical euthanasia (0-7 s). Body movement durations were also longer for KED (214 s) and TED (209 s) than for CO2 and electrical euthanasia (0-8 s). The highest percentages of broken skin (93%) and blood loss (96%) were observed for TED, followed by KED (71%, 68%), then CO2 (0%, 6%) and electrical euthanasia (0%, 3%). No significant differences (P = 0.1781) were observed for kill success rates with 98% for KED, 100% for TED, 97% for CO2, and 100% for electrical euthanasia at 4-min. Time to heartbeat cessation did not differ between KED (659 s), TED (427 s), or CO2 (583 s) euthanasia methods. No heartbeat was detected following electrical euthanasia. Blood plasma corticosterone levels did not differ between preeuthanasia or posteuthanasia from any of the methods applied. Based on these results each euthanasia method is acceptable for use with broiler breeders.

Assessment of Stabilized Hydrogen Peroxide for Use in Reducing Campylobacter Levels and Prevalence on Broiler Chicken Wings.

ABSTRACT: Poultry processing establishments use antimicrobial aids on broiler parts to minimize Campylobacter contamination. A silver-stabilized hydrogen peroxide (SHP) product was assessed for use as an antimicrobial processing aid. In a series of experiments, wing segments with skin were inoculated with 103 to 107 cells of Campylobacter coli, followed by treatment with SHP at 15,000 or 30,000 mg/L, peroxyacetic acid (PAA) at 300 or 3,000 mg/L (parts per million), or water. Each treatment was applied by either dip or spray. Rinsates from each wing segment were analyzed for direct counts and prevalence of Campylobacter. Treatment with SHP or PAA significantly reduced Campylobacter levels compared with water controls by up to 2.22 log CFU/mL. At high inoculum levels (106 to 107), SHP and PAA applied by dip had up to 1.27 log CFU/mL further reductions of Campylobacter levels compared with spray-treated wing segments. Additionally, wing drumettes were observed to retain higher levels and prevalence of Campylobacter recovery compared with wing flats at a low inoculation level (103). The results indicated that there was no carryover effect of SHP (same day versus 24 h) and dip treatment with SHP or PAA decreased Campylobacter recovery on broiler chicken wing segments compared with a water control. Although a 2-log reduction was modest, SHP had similar efficacy as the commonly used processing aid PAA. SHP shows potential for further investigation as an antimicrobial processing aid for use on poultry parts.

Impact of Skip-a-Day and Every-Day Feeding Programs for Broiler Breeder Pullets on the Recovery of Salmonella and Campylobacter following challenge.

The impact of restrictive feeding programs on Salmonella and Campylobacter colonization and persistence after challenge was investigated for broiler breeder pullets housed in an experimental rearing facility. Pullet-chicks were placed on litter in 3 feeding program rooms and each room contained 2 replicate pens. The feeding programs were: (1) Skip-a-day in trough feeders (SAD); (2) Every-day in trough feeders (EDT); (3) Every-day on the pen litter (EDL). On d 1, an additional group of hatchmate chicks were housed in a separate room and gavaged with Salmonella Typhimurium, to later serve as seeder chicks. After seeders were confirmed Salmonella-positive at wk 4, at wk 5 seeders were placed into each feeding program pen to commingle with 135 penmates. At 7, 9, 11, 17, 18, and 20 wk the litter surface in each pen was sampled using intermittently stepped-on drag-swabs. At 8, 12, 16, and 20 wk of age the ceca were sampled from 10 penmates/pen and 2 pooled spleen samples/pen were collected. SAD litter remained Salmonella-positive through 20 wk of age while EDL and EDT pens had no detectible litter Salmonella recovery by 18 and 20 wk. EDL fed pens had no direct (<102 cfu/mL) litter Salmonella recovery during the entirety of the experiment. Salmonella prevalence for ceca from SAD pullets was significantly (P < 0.05) higher at 8 wk (70%) compared to EDT (40%) and EDL (30%). At wk 12, SAD pullets for both on and off-feed sampling days had significantly higher Salmonella recovery (40%), compared to EDT and EDL (both at 5% recovery). By 16 and 20 wk, only the SAD pullets on the on-feed day (48 h without feed) had recovery of Salmonella at 20%. Salmonella recovery in pooled spleen samples did not appear associated with feeding treatments (22% positive). The remaining pullets challenged with Campylobacter at 21 wk produced similar trends as was seen for Salmonella. SAD program pullets had significantly higher Campylobacter from ceca (80 to 100%) compared to pullets on EDL (30 to 60%) or EDT (40 to 95%). These results suggest that using a Skip-a-Day feeding program for broiler breeder pullets contributes to persistently higher Salmonella and Campylobacter ceca colonization and litter prevalence.

Evaluation of the addition of organic acids in the feed and/or water for broilers and the subsequent recovery of Salmonella Typhimurium from litter and ceca.

Three separate broiler Salmonella Typhimurium challenge experiments were conducted evaluating efficacy of formic and propionic acid feed supplements to suppress environmental and cecal Salmonella Typhimurium prevalence. In experiment 1, broilers were provided feed with 1 kg/ton formic acid or 5 kg/ton propionic acid feed additives or a basal control diet. At the day of placement, half of the pens were inoculated with seeder chicks orally challenged with a marker strain of Salmonella Typhimurium and to yield challenged and adjacent nonchallenged pens. No differences in weekly litter samples or cecal Salmonella prevalence at 3 or 6 wk among feeding treatments were detected. In experiment 2, treatments were: 2 kg/ton propionic acid in feed, 1.0 mL/L formic acid in water, both propionic acid in feed and formic acid in water, and a basal control. Every pen was challenged with seeder chicks inoculated with Salmonella Typhimurium. By 6 wk all pens maintained detectable litter Salmonella, and broilers provided both propionic acid in feed and formic acid in water had the lowest cecal recovery (35%), compared to the control (60%). In experiment 3, treatments were: formic acid at 4 or 6 kg/ton from wk 0 to 6 or for only the last wk, propionic acid at 5 or 10 kg/ton for only the last wk, and a basal control. Each pen was challenged with Salmonella Typhimurium inoculated seeder chicks. By 6 wk, broilers fed formic acid (4 kg/ton) for the entire growout had no Salmonella-positive ceca (0/30). All treatments that provided acid supplemented feed for only the last wk had 3-13% Salmonella-positive ceca. These experiments indicate that adding formic acid to broiler feed appears to prevent Salmonella colonization from challenge pens entering into the adjacent nonchallenge pens. Feeding formic acid (4 kg/ton) for 6 wk resulted in no recovery of Salmonella from ceca compared to the control prevalence of 17%.

Impact of litter Salmonella status during feed withdrawal on Salmonella recovery from the broiler crop and ceca.

Research was conducted to evaluate the impact of litter Salmonella status during feed withdrawal on Salmonella recovery from the crop and ceca following feed withdrawal. In 4 experiments, pens of broilers in separate rooms were challenged with marker strains of either Salmonella Montevideo or Salmonella Heidelberg. Three d post challenge, a 12-hour feed withdrawal was initiated, and one pen of broilers was switched between rooms for each Salmonella serotype. In experiments 3 and 4, non-challenged broilers also were added to the Salmonella challenge pens. The litter of each pen was sampled before and after the feed withdrawal period, the broilers euthanized, and the crop and ceca aseptically removed for Salmonella isolation. Results showed that only the challenge Salmonella serotype was recovered from the litter in challenge pens where broilers were not moved, while both Salmonella serotypes were recovered from the litter of the switched pens. Salmonella was recovered from 56/80 crops and from 66/80 ceca of challenged broilers that remained in the challenge pens. The challenge Salmonella serotype was recovered from 50/80 crops and from 60/80 ceca, and the switched pens' litter Salmonella serotype was recovered from 19/80 crops but not from the ceca in broilers challenged with Salmonella and then switched between pens. For experiments 3 and 4, Salmonella was recovered from 19/40 crops and from only 2/40 ceca from the non-challenged broilers placed into the Salmonella challenge pens. The results from broilers that were switched between Salmonella challenge pens indicate that the recovery of Salmonella from the crop of broilers following feed withdrawal (on Salmonella-contaminated litter) appears to depend mainly on the initial challenge Salmonella (62%) and less on the litter Salmonella (24%) status during the feed withdrawal period. In contrast, only the initial challenge Salmonella was recovered from the ceca (79%) from broilers that remained in challenge pens or were switched between Salmonella challenge pens. However, when non-challenged broilers were placed into the Salmonella challenge pens and commingled during the 12-hour feed and water withdrawal period, it was possible to recover the pen litter Salmonella from the ceca at a low level of 5% (2/40).

Impact of alternative electrical stunning parameters on the ability of broilers to recover consciousness and meat quality.

Broilers in the United States are typically electrically stunned using low voltage-high frequency (12-38 V, ≥400 Hz) DC or AC water bath stunners. In the European Union, however, broilers are required to be electrocuted using high voltage-low frequency (50-150 V, 50-350 Hz) AC. Low voltage stunned broilers regain consciousness in the absence of bleeding. In contrast, high voltage stunned broilers die due to induction of cardiac fibrillation. For birds stunned with low voltage systems, concerns have been raised regarding animal welfare during bleeding. This work evaluated the impact of extended DC stunning duration and alternative stunning methods (DC+AC combination) on the recovery of bird consciousness and meat quality. In the absence of bleeding, broilers that were DC stunned for extended times (60, 90, or 120 s), 63, 10, or 0% of broilers, respectively, were able to recover consciousness. Alternative stunning protocols included water bath stunning broilers at 15 or 25 V DC for 10 s followed by plate stunning at 100, 110, or 120 V AC for 5 s. Prior to shackling, live body weight and shank width were measured and during stunning, maximum mA for both DC and AC stuns were recorded. All of the alternative stunning protocols (DC+AC) resulted in non-recoverable stunning. The maximum mA recorded during both DC and AC stunning were moderately/strongly (r = 0.54-0.81) correlated to body weight and poorly/moderately (r = 0.27-0.74) correlated to shank width. No significant differences for carcass or meat quality characteristics (hemorrhages, red wing tips, broken clavicles, pH, cook loss, a* and b* color values, and MORS shear energy) were detected between control (15 or 25 V DC only) and treatment groups (DC+AC combination stunning). The only significant different meat quality parameter was L* values where the lowest voltage group (15 V DC) had the darkest fillets (53.27) and the 15 V DC+100 V AC group had the lightest fillets (55.61) with all other groups intermediate. These data indicate that stunning parameters combining DC and AC stunning may be viable protocols when a stun-to-death is desired.

Carcass orientation and drip time affect potential surface water carryover for broiler carcasses subjected to a post-chill water dip or spray1.

To estimate the potential for residual antimicrobial solution carryover, surface water accumulation and loss was measured on post-chill carcasses that were either dipped or sprayed with water. For all experiments, broilers were slaughtered, soft or hard scalded, defeathered, and eviscerated. Carcasses were immersion chilled, allowed to drip, and post-chill carcass weight (CW) recorded. For water dip treatment, carcasses were dipped for 0.5 min in water and hung by a wing (n = 33) or a leg (n = 30) and CW recorded at 0, 0.5, 1, 2, and 5 min post-dip. For water spray treatment, individual carcasses were hung by either the wings (n = 35) or legs (n = 34) from a shackle suspended from a scale. Water was sprayed at 80 psi and post-spray CW recorded. Initial water accumulation (0 min) for dipped carcasses was not significantly different (P > 0.05) for carcasses hung by the leg (101.0 g) or wing (108.8 g). Following the 5 min drip time, 31 g of water remained on the carcasses hung by the leg and only 10 g on carcasses hung by the wing (P < 0.05). When carcasses were sprayed with water, initial water accumulation (0 min) was 62 g for carcasses hung by the legs and 60 g for carcasses hung by the wings (P > 0.05). Following the 5 min drip time, 1 g or no water remained on the sprayed carcasses (P > 0.05). Carcasses that were dipped and hung by a leg for 5 min retained significantly more water (31 g) than carcasses that were dipped and hung by a wing (10 g) or sprayed carcasses hung either way (0.3 g) (P < 0.05). Post-chill water dip resulted in significantly higher initial carcass water accumulation than spraying (105 g vs. 61 g, P < 0.05). Carcass orientation during dripping only affected the amount of retained water for dipped carcasses. Dipped carcasses hung by a leg have the highest potential for residual carcass antimicrobial solution carryover and sprayed carcasses hung by either orientation have the lowest potential for residual antimicrobial solution carryover.

Influence of commercial laying hen housing systems on the incidence and identification of Salmonella and Campylobacter.

The housing of laying hens is important for social, industrial, and regulatory aspects. Many studies have compared hen housing systems on the research farm, but few have fully examined commercial housing systems and management strategies. The current study compared hens housed in commercial cage-free aviary, conventional cage, and enriched colony cage systems. Environmental and eggshell pool samples were collected from selected cages/segments of the housing systems throughout the production cycle and monitored for Salmonella and Campylobacter prevalence. At 77 wk of age, 120 hens per housing system were examined for Salmonella and Campylobacter colonization in the: adrenal glands, spleen, ceca, follicles, and upper reproductive tract. All isolates detected from environmental swabs, eggshell pools, and tissues were identified for serotype. Two predominant Salmonella were detected in all samples:S.Braenderup andS.Kentucky.Campylobacter coli and C. jejuni were the only Campylobacter detected in the flocks. Across all housing systems, approximately 7% of hens were colonized with Salmonella, whereas >90% were colonized with Campylobacter Salmonella Braenderup was the isolate most frequently detected in environmental swabs (P<0.0001) and housing system impacted Salmonella spp. shedding (P<0.0001).Campylobacter jejuni was the isolate most frequently found in environmental swabs (P<0.01), while housing system impacted the prevalence of C. coli and jejuniin ceca (P<0.0001). The results of this study provide a greater understanding of the impact of hen housing systems on hen health and product safety. Additionally, producers and academia can utilize the findings to make informed decisions on hen housing and management strategies to enhance hen health and food safety.

The addition of charcoals to broiler diets did not alter the recovery of Salmonella Typhimurium during grow-out.

Two experiments evaluated prebiotics added to feed on the recovery of Salmonella in broilers during grow-out and processing. In Experiment 1, "seeder" chicks were inoculated with Salmonella Typhimurium and placed with penmates. Treatments were: basal control diet, added 0.3% bamboo charcoal, 0.6% bamboo charcoal, or 0.12% Aromabiotic (medium chain fatty acids). The ceca from seeders and penmates were sampled to confirm Salmonella colonization at 3, 4, and 6 wk, and pen litter was sampled weekly. At 3 wk, charcoal fed chicks had significantly lower cecal recovery (37% lower) of Salmonella via direct plating but no differences at wk 4 or 6. At 6 wk, broilers fed Aromabiotic had no recovery of Salmonella from ceca with direct plating and significantly, 18%, lower recovery with enrichment. In Experiment 2, the treatments were: basal control diet, added 0.3% bamboo charcoal, 0.3% activated bamboo charcoal, or 0.3% pine charcoal. At placement, 2 seeders were challenged with Salmonella and commingled with penmates and ceca sampled at 1 and 2 wk, and ceca from 5 penmates/pen at 3 to 6 wk. Weekly, the pH of the crop and duodenum was measured from 1 penmate/pen and the litter surface sampled. At the end of grow-out broilers were processed. Results showed that penmates had colonized at 1 and 2 wk. Cecal Salmonella showed no differences except at 4 wk, when activated bamboo charcoal had a 18% lower recovery of Salmonella (enrichment) compared to the control (88%). Similar to Experiment 1, the recovery of Salmonella from the litter was not significantly different among treatments, however an overall decrease in recovery by 4 wk with direct plating reoccurred. The pH of the duodenum and the crop were not different among treatments. Crop pH (6.0) for all treatments were significantly higher at wk 1 compared to wk 2 to 6. Charcoals had minimal effect on Salmonella recovery in the ceca, but following defeathering, broilers fed charcoals had significantly lower Salmonella recovery from breast skin (charcoals 5+/60 compared to control 8+/20). While the addition of charcoals to broilers feed did not significantly affect Salmonella recovery during production (from litter or ceca samples) there was a lower Salmonella recovery from breast skin following scalding and defeathering.

Prevalence and Serogroup Diversity of Salmonella for Broiler Neck Skin, Whole Carcass Rinse, and Whole Carcass Enrichment Sampling Methodologies following Air or Immersion Chilling.

The purpose of this study was to evaluate neck skin (NS), whole carcass rinse (WCR), and whole carcass enrichment (WCE) sampling procedures for Salmonella isolation and serogroup identification from the same broiler chicken carcass treated with air or immersion chilling. Commercially processed and eviscerated broiler carcasses were collected from a commercial processing plant, individually bagged, and transported to the pilot processing plant. In experiment 1, carcasses were air chilled to 4°C. In experiment 2, carcasses were immersion chilled with or without chlorine. After air chilling, Salmonella was detected on 78% of NS and 89% of WCE samples. Only one Salmonella serogroup was detected from each of 13 Salmonella-positive NS samples, and two serogroups were detected on 1 Salmonella-positive NS sample. Only one Salmonella serogroup was detected from each of 13 Salmonella-positive WCE samples, and two serogroups were detected from 3 Salmonella-positive WCE samples. After immersion chilling without chlorine, Salmonella was detected on 38% of NS, 45% of WCR, and 100% of WCE samples. Without chlorine, the 15 Salmonella-positive NS samples included 14 samples with one serogroup and 1 sample with two serogroups. Only one Salmonella serogroup was detected from WCR samples after immersion chilling. Of 40 Salmonella-positive WCE samples, 23 had a one, 14 had two, and 3 had three Salmonella serogroups. After immersion chilling with chlorine, Salmonella was detected on 35% of NS, 0% of WCR, and 90% of WCE samples. With chlorine, the 14 Salmonella-positive NS samples included 11 samples with one serogroup and 3 samples with two serogroups. No Salmonella serogroups were detected from WCR samples after immersion chilling with 20 mg/liter free chlorine. The 36 Salmonella-positive WCE samples included 21 samples with one serogroup and 15 samples with two serogroups. NS and WCE sampling methodologies yielded similar prevalence and serogroup diversity after air chilling. However, after immersion chilling with or without chlorine, WCE sampling yielded significantly higher (α ≤ 0.05) prevalence and serogroup diversity than either NS or WCR sampling methodologies.

Microbiological impact of three commercial laying hen housing systems.

Hen housing for commercial egg production continues to be a societal and regulatory concern. Controlled studies have examined various aspects of egg safety, but a comprehensive assessment of commercial hen housing systems in the US has not been conducted. The current study is part of a holistic, multidisciplinary comparison of the diverse aspects of commercial conventional cage, enriched colony cage, and cage-free aviary housing systems and focuses on environmental and egg microbiology. Environmental swabs and eggshell pools were collected from all housing systems during 4 production periods. Total aerobes and coliforms were enumerated, and the prevalence of Salmonella and Campylobacter spp. was determined. Environmental aerobic and coliform counts were highest for aviary drag swabs (7.5 and 4.0 log cfu/mL, respectively) and enriched colony cage scratch pad swabs (6.8 and 3.8 log cfu/mL, respectively). Aviary floor and system wire shell pools had the greatest levels of aerobic contamination for all eggshell pools (4.9 and 4.1 log cfu/mL, respectively). Hens from all housing systems were shedding Salmonella spp. (89-100% of manure belt scraper blade swabs). The dry belt litter removal processes for all housing systems appear to affect Campylobacter spp. detection (0-41% of manure belt scraper blade swabs) considering detection of Campylobacter spp. was much higher for other environmental samples. Aviary forage area drag swabs were 100% contaminated with Campylobacter spp., whereas enriched colony cage scratch pads had a 93% positive rate. There were no differences in pathogen detection in the shell pools from the 3 housing systems. Results indicate egg safety is enhanced when hens in alternative housing systems use nest boxes. Additionally, current outcomes indicate the use of scratch pads in hen housing systems needs to be more thoroughly investigated for effects on hen health and egg safety.

The effect of high-level chlorine carcass drench on the recovery of Salmonella and enumeration of bacteria from broiler carcasses.

A study was conducted to determine the bacteriological effect of exposing processed broiler carcasses to a high (10-fold increase) concentration chlorinated drench. During each of 6 replicate trials, eviscerated prechill carcasses were obtained from a commercial processing plant and chlorine-treated carcasses were subjected to a 1-min drench in 500 mL of a 500 mg/kg chlorine solution (sodium hypochlorite). Water-drenched carcasses were treated the same way except water was used in place of chlorinated water drench. Control carcasses were not drenched. All carcasses were then subjected to a whole carcass rinse (WCR) in 450 mL of buffered peptone water, from which 50 mL of the rinsate was removed for enumeration of total aerobic bacteria (APC), Escherichia coli, and total coliforms (TC). The entire carcass was then incubated 24 h at 37°C (whole carcass enrichment, WCE) for recovery of Salmonella. Levels of bacteria recovered from WCR were lower by 0.6 log10 cfu/mL for APC, 0.8 for E. coli, and 0.9 for TC when carcasses were drenched with water compared with undrenched control levels. Similarly, the levels of bacteria recovered from WCR were further lower by 1.0 log10 cfu/mL for APC, 0.5 for E. coli, and 0.5 for TC, when carcasses were drenched with 500 mg/kg of chlorine compared with water. However, there was no significant difference (P > 0.05) in prevalence of Salmonella among the treatments (29% positive for control, 26% positive for water, 38% positive for chlorinated). These results indicate that drenching eviscerated carcasses with water or chlorinated water at 500 mg/kg significantly, but minimally, reduces the numbers of APC, E. coli, and TC bacteria recovered compared with undrenched carcasses. However, neither drenching carcasses with water or high chlorine had an effect on the prevalence of Salmonella that remain with the carcass as determined by WCE. The results of this study confirms the importance of maintaining and replenishing free chlorine for optimal antimicrobial activity, because chlorine at 500 mg/kg was rapidly used within 1 min of exposure to the carcass to <10 mg/kg.

Impact of broiler processing scalding and chilling profiles on carcass and breast meat yield.

The effect of scalding and chilling procedures was evaluated on carcass and breast meat weight and yield in broilers. On 4 separate weeks (trials), broilers were subjected to feed withdrawal, weighed, and then stunned and bled in 4 sequential batches (n = 16 broilers/batch, 64 broilers/trial). In addition, breast skin was collected before scalding, after scalding, and after defeathering for proximate analysis. Each batch of 16 carcasses was subjected to either hard (60.0°C for 1.5 min) or soft (52.8°C for 3 min) immersion scalding. Following defeathering and evisceration, 8 carcasses/batch were air-chilled (0.5°C, 120 min, 86% RH) and 8 carcasses/batch were immersion water-chilled (water and ice 0.5°C, 40 min). Carcasses were reweighed individually following evisceration and following chilling. Breast meat was removed from the carcass and weighed within 4 h postmortem. There were significant (P < 0.05) differences among the trials for all weights and yields; however, postfeed withdrawal shackle weight and postscald-defeathered eviscerated weights did not differ between the scalding and chilling treatments. During air-chilling all carcasses lost weight, resulting in postchill carcass yield of 73.0% for soft-scalded and 71.3% for hard-scalded carcasses, a difference of 1.7%. During water-chilling all carcasses gained weight, resulting in heavier postchill carcass weights (2,031 g) than for air-chilled carcasses (1,899 g). Postchill carcass yields were correspondingly higher for water-chilled carcasses, 78.2% for soft-scalded and 76.1% for hard-scalded carcasses, a difference of 2.1%. Only in trials 1 and 4 was breast meat yield significantly lower for hard-scalded, air-chilled carcasses (16.1 and 17.5%) than the other treatments. Proximate analysis of skin sampled after scalding or defeathering did not differ significantly in moisture (P = 0.2530) or lipid (P = 0.6412) content compared with skin sampled before scalding. Skin protein content was significantly higher (P < 0.05) for prescald and soft-scalded skin samples than for hard-scalded or soft or hard-scalded skin samples after defeathering. The hard-scalding method used in this experiment did not result in increased skin lipid loss either before or after defeathering.

Hot-boning enhances cook yield of boneless skinless chicken thighs.

Three experiments were conducted to evaluate the effects of postmortem deboning time on cook yield of boneless skinless chicken thighs. In experiment 1, chicken thigh meat was deboned at 0.75 (hot-bone), 2, and 24 h postmortem (PM) and trimmed to obtain mainly iliotibialis muscle. Samples were cooked directly from a frozen state. Cook yield of the muscle was significantly influenced by PM deboning time. Hot-boned thighs exhibited a 7% greater cook yield than the samples deboned at 24 h. In experiment 2, boneless skinless chicken thighs were deboned at 0.3, 2, and 24 h PM and cooked directly from a fresh, never-frozen state at 24 h PM. Cook yield of the hot-boned thighs was significantly higher than those of the 2 and 24 h deboned samples, which did not differ from each other. In experiment 3, whole legs (thigh + drumstick) were cut from the carcass backbone at 0.3 (hot-cut), 2, and 24 h PM. Thighs were separated from the legs (drumsticks) at either the same time the whole legs were removed from the carcasses or at 24 h PM. Intact thighs (bone in) were cooked fresh at 24 h PM. Color of fresh thigh muscles, cook yield, and Warner-Bratzler shear force of cooked samples were measured. Cook yield of the thighs cut from the backbone before chilling was significantly higher than those cut from the carcasses at 2 and 24 h PM, which did not differ from each other. The PM time at which intact thighs were separated from the leg (drumstick) did not influence cook yield. These results demonstrate that postmortem deboning time can significantly affect cook yield of boneless skinless chicken thigh products. Deboning chicken thighs after chilling reduces the cook yield. Differences in the cook yield of thighs may also result from the removal of whole chicken legs from the carcass backbone.

Recovery of Salmonella serovar Enteritidis from inoculated broiler hatching eggs using shell rinse and shell crush sampling methods.

This study compared the recovery of Salmonella from hatching eggs using 3 sampling methods (eggshell rinsing, eggshell crush following a previous rinse, and eggshell crush without previous rinse). Eggshells were drop-inoculated with approximately 10(1), 10(2), or 10(3) cfu/eggshell of Salmonella Enteritidis and allowed to dry at room temperature for 1 or 24 h. For the shell rinse groups, each inoculated egg was rinsed with buffered peptone water. These rinsed eggs were used for the shell crush with previous rinse groups, and each egg was aseptically cracked, the contents discarded, and the eggshell and membranes crushed with buffered peptone water. This same crush procedure was used for the shell crush without previous shell rinse eggs. The recovery of Salmonella 1 h after inoculation for shell rinse sampled eggs was 16% positive at 10(1), 49% at 10(2), and 93% at 10(3) cfu/eggshell challenge. For the shell crush with previous shell rinse, sampled egg recovery was 0% positive at 10(1), 3% at 10(2), and 17% at 10(3) cfu/eggshell. For the shell crush, sampled eggs had recovery of 23% positive at 10(1), 69% at 10(2), and 96% at 10(3) cfu/eggshell challenge. The recovery of Salmonella 24 h after inoculation for the shell rinse eggs was 3% positive at 10(1), 12% at 10(2), and 22% at 10(3) cfu/eggshell challenge; recovery for shell crush with previous shell rinse sampling was 2% positive at 10(1), 8% at 10(2), and 5% at 10(3) cfu/eggshell challenge; and for the shell crush sampling recovery was 2% at 10(1), 32% at 10(2), and 42% at 10(3) cfu/eggshell challenge. Eggshell crush was a more sensitive (∼10 percentage points) sampling method than eggshell rinse at both 1 and 24 h, but both methods were equally optimal when the inoculum was at 10(3) and samples were collected after 1 h. Waiting 24 h after inoculation to sample significantly lowered the recovery for both the shell rinse and shell crush sampling methods by ∼40 percentage points.

Sampling naturally contaminated broiler carcasses for Salmonella by three different methods.

Postchill neck skin maceration (NSM) and whole-carcass rinsing (WCR) are frequently used methods to detect salmonellae from processed broilers. These are practical, nondestructive methods, but they are insensitive and may result in false negatives (20 to 40%). Neck skin samples comprise only 4% of the skin from the broiler carcass by weight, while WCR will not detect firmly attached Salmonella organisms and only 7.5% of the rinsate is utilized. Whole-carcass enrichment (WCE) involves incubation of the whole carcass overnight in a preenrichment broth and can recover as few as 8 inoculated Salmonella cells per carcass. The objective of this study was to use NSM, WCR, and WCE sampling to detect naturally occurring Salmonella from the same commercially processed broiler either prechill or postchill. Ten carcasses were obtained prechill and another 10 postchill on each of two replicate days from each of two commercial processing plants. From each carcass, 8.3 g of neck skin was sampled, and then the carcass was rinsed with 400 ml of 1% buffered peptone water. Thirty milliliters was removed and incubated (WCR), and the remaining 370 ml of broth and the carcass were incubated at 37°C for 24 h (WCE). Overall, Salmonella organisms were detected on 21, 24, and 32 of 40 prechill carcasses by NSM, WCR, and WCE, respectively, while 2, 2, and 19 of 40 postchill carcasses were positive by the respective methods. Prechill carcasses were 64% (77 of 120) positive for Salmonella, while postchill carcasses were 19% (23 of 120) positive. Commercial processing reduced the positive-sample prevalence by 45%. Salmonella organisms were detected on 20% (24 of 120) of the samples from plant 1 and 63% (76 of 120) of the carcasses from plant 2. This study demonstrates significant differences in the results for Salmonella prevalence among sampling methods both before and after immersion chilling, as well as between processing plants on days that samples were taken.

Evidence for horizontal and vertical transmission in Campylobacter passage from hen to her progeny.

Campylobacter is an important human pathogen, and consumption of undercooked poultry has been linked to significant human illnesses. To reduce human illness, intervention strategies targeting Campylobacter reduction in poultry are in development. For more than a decade, there has been an ongoing national and international controversy about whether Campylobacter can pass from one generation of poultry to the next via the fertile egg. We recognize that there are numerous sources of Campylobacter entry into flocks of commercial poultry (including egg transmission), yet the environment is often cited as the only source. There has been an abundance of published research globally that refutes this contention, and this article lists and discusses many of them, along with other studies that support environment as the sole or primary source. One must remember that egg passage can mean more than vertical, transovarian transmission. Fecal bacteria, including Campylobacter, can contaminate the shell, shell membranes, and albumen of freshly laid fertile eggs. This contamination is drawn through the shell by temperature differential, aided by the presence of moisture (the "sweating" of the egg); then, when the chick emerges from the egg, it can ingest bacteria such as Campylobacter, become colonized, and spread this contamination to flock mates in the grow house. Improvements in cultural laboratory methods continue to advance our knowledge of the ecology of Campylobacter, and in the not-so-distant future, egg passage will not be a subject continuously debated but will be embraced, thus allowing the development and implementation of more effective intervention strategies.

Isolation of Campylobacter from circulating blood of commercial broilers.

Campylobacter spp. are present in organs and tissues of broiler chickens but the dissemination route is unclear. The aim of the current study was to determine Campylobacter prevalence within circulating blood of commercial broilers. Broilers were acquired from 19 flocks originating from three commercial poultry processing companies. Using aseptic blood collection techniques, 5 ml of circulating blood was collected from each bird and the sample analyzed for Campylobacter. The Campylobacter colonization status of each bird was determined by aseptically sampling and analyzing the ceca. Campylobacter was recovered from 58% (11/19) of flocks sampled. From the 248 total birds sampled, 12% and 46% of the birds had Campylobacter in the blood and ceca, respectively. This study documents Campylobacter prevalence in the circulating blood of commercially raised broilers. Campylobacter presence in the circulatory system may indicate the path used by the organism for rapid dissemination to organs and tissues. From a processing viewpoint, Campylobacter presence in circulating blood of market-age broilers may increase the likelihood of cross-contamination between birds during slaughter.

Comparison of shell bacteria from unwashed and washed table eggs harvested from caged laying hens and cage-free floor-housed laying hens.

These studies evaluated the bacterial level of unwashed and washed shell eggs from caged and cage-free laying hens. Hy-Line W-36 White and Hy-Line Brown laying hens were housed on all wire slats or all shavings floor systems. On the sampling days for experiments 1, 2, and 3, 20 eggs were collected from each pen for bacterial analyses. Ten of the eggs collected from each pen were washed for 1 min with a commercial egg-washing solution, whereas the remaining 10 eggs were unwashed before sampling the eggshell and shell membranes for aerobic bacteria and coliforms (experiment 1 only). In experiment 1, the aerobic plate counts (APC) of unwashed eggs produced in the shavings, slats, and caged-housing systems were 4.0, 3.6, and 3.1 log(10) cfu/mL of rinsate, respectively. Washing eggs significantly (P < 0.05) reduced APC by 1.6 log(10) cfu/mL and reduced the prevalence of coliforms by 12%. In experiment 2, unwashed eggs produced by hens in triple-deck cages from 57 to 62 wk (previously housed on shavings, slats, and cages) did not differ, with APC ranging from 0.6 to 0.8 log(10) cfu/mL. Washing eggs continued to significantly reduce APC to below 0.2 log(10) cfu/mL. In experiment 3, the APC for unwashed eggs were within 0.4 log below the APC attained for unwashed eggs in experiment 1, although hen density was 28% of that used in experiment 1. Washing eggs further lowered the APC to 0.4 to 0.7 log(10) cfu/mL, a 2.7-log reduction. These results indicate that shell bacterial levels are similar after washing for eggs from hens housed in these caged and cage-free environments. However, housing hens in cages with manure removal belts resulted in lower APC for both unwashed and washed eggs (compared with eggs from hens housed in a room with shavings, slats, and cages).