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.

Microbial recovery from genetically featherless broiler carcasses after forced cloacal fecal expulsion.

A study was conducted to determine external microbiology of genetically featherless broiler carcasses after forced cloacal fecal expulsion. Full-fed featherless broilers were placed into coops, transported, unloaded, shackled, stunned, suffocated, weighed, and divided into 3 treatments groups. Carcasses were transferred to a separate shackle line and passed through a machine designed to induce defecation (squeeze) and then remove external feces (wash). Treatments were obtained by turning the squeezing and washing components on or off. Treatments were as follows: S carcasses were squeezed but not washed; W carcasses were not squeezed but were washed; and SW carcasses were squeezed and washed. Concentrations of total aerobic microorganisms (AB), Escherichia coli (EC), coliforms (CF), and Campylobacter (CPY) recovered from whole carcass rinses did not vary with treatment (P > 0.05). However, counts of Salmonella (SAL) in rinses of S carcasses were 1.4 log(10) cfu/mL greater than counts of SAL found in rinses of SW carcasses (P < 0.05). The SAL prevalence was similar for S (86% positive), W (90% positive), and SW (83% positive) carcasses (P > 0.05). Populations of AB and CF recovered from wash water (water applied in the machine after fecal expulsion) for SW carcasses were significantly higher by 3.1 and 1.5 log(10) cfu/mL, respectively, than the populations of the same bacteria recovered from wash water for W carcasses (P < 0.05). Levels of EC and CPY recovered from wash water did not vary with treatment. There was no difference in CPY and SAL prevalence in water collected after washing W carcasses or SW carcasses (P > 0.05). Data from the present study show that controlled cloacal fecal expulsion followed by carcass washing immediately after slaughter can be used to minimize the numbers of carcass Salmonella and can reduce the likelihood of visible carcass fecal contamination or cross-contamination to other carcasses and processing equipment.

Identification of yeasts isolated from commercial shell eggs stored at refrigerated temperatures.

Yeasts and molds can grow on or in eggs, causing spoilage. Washed and unwashed eggs (treatments) were collected aseptically on three separate days (replications) from a commercial processing facility and stored for 10 weeks at 4 degrees C. Ten eggs from each treatment were sampled weekly (110 eggs per treatment per replication). Yeasts and molds were enumerated from external shell rinses by plating onto acidified potato dextrose agar. Yeast colonies were picked randomly and stored for subsequent identification by gas chromatographic analysis of fatty acid methyl esters using the MIDI Microbial Identification System. Of 688 isolates analyzed, 380 were identified to genus or species. Genera identified by this method included Candida, Cryptococcus, Hansenula, Hyphopichia, Metschnikowia, Rhodotorula, Sporobolomyces, and Torulaspora. Candida spp. accounted for 84.5% (321 of 380) of the isolate identifications. Candida famata was the most prevalent species (n = 120), followed by Candida lusitaniae (n = 38). A group of 20 isolates was subjected to molecular or biochemical analyses for comparison with the MIDI results. Biochemical tests were performed using automatic and mini systems. Results of biochemical tests and ribosomal DNA sequencing were in agreement for 11 of the isolates, but only 7 of the 20 MIDI-identified isolates were in agreement with the sequencing results. C. famata, an anamorph of Debaryomyces hansenii var. hansenii, was the most commonly identified isolate by all methods. These data indicate that there was limited correlation between results obtained with the MIDI system and the information obtained from molecular databases. However, both systems were able to correctly identify C. famata, the species most often isolated throughout egg storage.

Microbiology of broiler carcasses and chemistry of chiller water as affected by water reuse.

A study was conducted to determine the effects of treating and reusing poultry chiller water in a commercial poultry processing facility. Broiler carcasses and chiller water were obtained from a commercial processing facility which had recently installed a TOMCO Pathogen Management System to recycle water in sections 2 and 3 of two 3-compartment chillers. In this system, reused water is blended with fresh water to maintain the chiller volume. Carcasses were sampled prechill and postchill (final exit), and chiller water was sampled from the beginning and end of each of the 3 sections. Carcasses were subjected to a whole carcass rinse (WCR) in 0.1% peptone. Numbers of Escherichia coli (EC), coliforms (CF), and Campylobacter (CPY) were determined from the WCR and chiller water samples. Prevalence of Salmonella (SAL) was also determined on the WCR and chiller water samples. On average, prechill levels of bacteria recovered from rinses were 2.6, 2.9, and 2.6 log10 cfu/mL for EC, CF, and CPY, respectively. Ten out of 40 (25%) prechill carcasses were positive for SAL. After chilling, numbers of EC, CF, and CPY recovered from carcass rinses decreased by 1.5, 1.5, and 2.0 log10 cfu/mL, respectively. However, 9 out of 40 (22%) postchill carcasses were positive for SAL. When the chiller water samples were tested, counts of EC, CF, and CPY were found only in water collected from the first section of the chiller (inlet and outlet). Two of 4 water samples collected from the inlet of the first section tested positive for SAL. This study shows that fresh and reused water can be used to cool poultry in chiller systems to achieve a reduction in numbers of bacteria (EC, CF, and CPY) or equivalent prevalence (SAL) of bacteria recovered from broiler carcasses.

Recovery of bacteria from broiler carcasses after immersion chilling in different volumes of water, part 2.

Experiments were conducted to determine the relationship between poultry chilling water volume and carcass microbiology. In the first study, the volume of water used during immersion chilling was found to have a significant effect on the counts of bacteria recovered from broiler carcass halves; however, these volumes (2.1 and 16.8 L/kg) were extreme and did not reflect commercial levels. A second study using commercial chilling volumes was conducted with 3.3 L/kg (low) or 6.7 L/kg (high) distilled water in the chiller. Prechill broiler carcasses were removed from a commercial processing line, cut into left and right halves, and one-half of each pair was individually chilled in a bag containing low or high volume of water. Bags containing halves were submersed in a secondary chill tank containing approximately 150 L of an ice-water mix (0.6 degrees C). After 45 min, halves were removed, allowed to drip for 5 min, and rinsed with 100 mL of sterile water for 1 min. Rinses were analyzed for total aerobic bacteria, Escherichia coli, Enterobacteriaceae, and Campylobacter. When the numbers of bacteria in the half-carcass rinses (HCR) were compared, counts recovered from halves chilled in a low volume of water were the same as those recovered from the halves chilled with a high volume of water (P > 0.05). Levels found in the HCR ranged from 4.0 to 4.2 log(10) cfu/mL for aerobic bacteria, 3.3 to 3.5 log(10) cfu/mL for E. coli, 3.6 to 3.8 log(10) cfu/mL for Enterobacteriaceae, and 2.4 to 2.6 log(10) cfu/mL for Campylobacter. Data were also analyzed using a paired comparison t-test, and this analysis showed that there was no difference (P > 0.05) in the numbers of aerobic bacteria, E. coli, Enterobacteriaceae, or Campylobacter recovered from paired-halves chilled in different volumes of water. The present study shows that under the conditions outlined in this experiment, doubling the amount of water during immersion chilling (3.3 vs. 6.7 L/kg) did not improve the removal of bacteria from the surfaces of chilled carcasses.

Effect of dry air or immersion chilling on recovery of bacteria from broiler carcasses.

A study was conducted to investigate the effect of chilling method (air or immersion) on concentration and prevalence of Escherichia coli, coliforms, Campylobacter, and Salmonella recovered from broiler chicken carcasses. For each of four replications, 60 broilers were inoculated orally and intracloacally with 1 ml of a suspension containing Campylobacter at approximately 10(8) cells per ml. After 1 day, broilers were inoculated with 1 ml of a suspension containing Salmonella at approximately 10(8) cells per ml. Broilers were processed, and carcasses were cooled with dry air (3.5 m/s at -1.1 degrees C for 150 min) or by immersion chilling in ice water (0.6 degrees C for 50 min). Concentrations of E. coli, coliforms, Campylobacter, and Salmonella recovered from prechill carcasses averaged 3.5, 3.7, 3.4, and 1.4 log CFU/ml of rinse, respectively. Overall, both chilling methods significantly reduced bacterial concentrations on the carcasses, and no difference in concentrations of bacteria was observed between the two chilling methods (P < 0.05). Both chilling methods reduced E. coli and coliforms by 0.9 to 1.0 log CFU/ml. Air and immersion chilling reduced Campylobacter by 1.4 and 1.0 log CFU/ml and reduced Salmonella by 1.0 and 0.6 log CFU/ml, respectively. Chilling method had no effect on the prevalence of Campylobacter and Salmonella recovered from carcasses. These results demonstrate that air- and immersion-chilled carcasses without chemical intervention are microbiologically comparable, and a 90% reduction in concentrations of E. coli, coliforms, and Campylobacter can be obtained by chilling.

Partitioning of external and internal bacteria carried by broiler chickens before processing.

Broiler chickens from the loading dock of a commercial processing plant were sampled to determine the incidence and counts of coliforms, Escherichia coli, and pathogenic bacteria. Feathers were removed by hand from ten 6-week-old chickens from each of seven different flocks and rinsed in 400 ml of 0.1% peptone water. Heads and feet were removed and rinsed, and the picked carcass was also rinsed, each in 200 ml. The ceca, colon, and crop were aseptically removed and stomached separately in 100 ml of peptone water. Campylobacter was present in six of the seven flocks. Salmonella was isolated from 50 of the 70 carcasses, with at least 2 positive carcasses in each flock, and five-tube most-probable-number (MPN) assays were performed on positive samples. Significantly (P < 0.05) more coliforms and E. coli were found in the ceca than in the feathers, which in turn carried more than the other samples, but total external and internal counts were roughly equivalent. Counts of Campylobacter were higher in the ceca and colon than in the other samples. Salmonella was isolated in external samples from 46 of the 50 positive carcasses compared with 26 positive internal samples or 17 positives in the ceca alone. The total MPN of Salmonella was approximately equivalent in all samples, indicating that contamination was distributed through all external and internal sampling locations. Salmonella-positive samples did not carry higher counts of coliforms or E. coli, and there were no significant correlations between the indicators and pathogens in any sample. Campylobacter numbers in the ceca were correlated with Campylobacter numbers in the feathers and colon, but Salmonella numbers in those samples were not correlated. The pattern of bacterial contamination before processing is complex and highly variable.

Recovery of bacteria from broiler carcasses after spray washing with acidified electrolyzed water or sodium hypochlorite solutions.

A study was conducted to investigate the effects of spray washing broiler carcasses with acidified electrolyzed oxidizing water (EO) or sodium hypochlorite (HOCl) solutions for 5, 10, or 15 s. Commercial broiler carcasses were contaminated with 0.1 g of broiler cecal contents inoculated with 10(5) cells of Campylobacter and 10(5) cells of nalidixic acid-resistant Salmonella. Numbers of bacteria recovered from unwashed control carcasses were 6.7, 5.9, 6.3, and 3.9 log(10) cfu/mL for total aerobic bacteria, Escherichia coli, Campylobacter, and Salmonella, respectively. Washing in either EO (50 mg/L of sodium hypochlorite, pH 2.4, oxidation reduction potential of 1,180 mV) or HOCl (50 mg/L of sodium hypochlorite, pH 8.0) significantly reduced the levels of bacteria recovered from carcasses (P < 0.05). Carcasses washed with EO had slightly lower levels of total aerobic bacteria (0.3 log(10) cfu/mL) and E. coli (0.2 log(10) cfu/mL) than HOCl-treated carcasses; however, populations of Campylobacter and Salmonella were comparable after washing in either solution. Increasing the carcass washing time from 5 to 10 s lowered the levels of total aerobic bacteria (6.1 vs. 5.8 log(10) cfu/mL), E. coli (4.6 vs. 4.1 log(10) cfu/mL), Campylobacter (5.2 vs. 4.2 log(10) cfu/mL), and Salmonella (2.0 vs. 1.2 log(10) cfu/mL), but no further microbiological reductions occurred when washing time was extended from 10 to 15 s. Data from the present study show that washing poultry carcasses with EO is slightly better (total aerobic bacteria and E. coli) or equivalent to (Campylobacter and Salmonella) washing with HOCl. Washing broiler carcasses for a period equivalent to 2 inside-outside bird washers (10 s) provided greater reductions in carcass bacterial populations than periods simulating 1 (5 s) or 3 inside-outside bird washers (15 s).

Effect of external or internal fecal contamination on numbers of bacteria on prechilled broiler carcasses.

During processing, fecal material may contact broiler carcasses externally or internally. A study was conducted to determine the effect of external vs. internal fecal contamination on numbers of bacteria on broiler carcasses. In each of 3 trials, 12 carcasses just prior to evisceration were obtained from a commercial processing plant, placed on a shackle line, and eviscerated with commercial equipment in a pilot scale processing plant. Also, approximately 20 intestinal tracts were collected from the processing plant; then cecal contents were collected and pooled. One gram of cecal content was placed on the exterior breast skin (external), inside the carcass cavity (internal), or not applied (control). All carcasses were held 10 min, then placed on the shackle line and passed through a commercial inside-outside bird washer set at 552 kPa, 5 s dwell time, using approximately 189 L per min of tap water at ambient temperature. After a 1-min drip, whole carcass rinses were conducted on each carcass, and coliforms, Escherichia coli, and Campylobacter counts were determined and reported as log cfu/mL of rinse. External carcass contamination resulted in significantly higher (P<0.05) coliform, E. coli, and Campylobacter numbers than internal contamination (5.0 vs. 4.5, 4.9 vs. 4.2, and 3.6 vs. 2.6, respectively). Control carcass counts were significantly lower than external or internal carcass contamination counts for coliforms (3.7), E. coli (3.6), and Campylobacter (2.2). External contamination resulted in higher numbers of bacteria after carcass washing, but carcasses with internal contamination still have higher numbers of bacteria after washing than carcasses without applied contamination.

Spoilage microflora of broiler carcasses washed with electrolyzed oxidizing or chlorinated water using an inside-outside bird washer.

The effect of acidic, electrolyzed oxidizing (EO) water and chlorinated water on the spoilage microflora of processed broiler carcasses was examined. Carcasses were sprayed for 5 s at 80 psi with tap, chlorinated, or EO water in an inside-outside bird washer. Treated carcasses were then stored at 4 degrees C for 0, 3, 7, or 14 d, and the microbial flora of the carcasses was sampled using the whole-carcass rinse procedure. Populations of psychrotrophic bacteria and yeasts in the carcass rinsates were enumerated. Results indicated that immediately after spraying the carcasses, significantly fewer psychrotrophic bacteria were recovered from carcasses sprayed with chlorinated or EO water than from carcasses sprayed with tap water. Furthermore, significantly fewer yeasts were recovered from carcasses sprayed with EO water than from carcasses sprayed with tap or chlorinated water. The population of psychrotrophic bacteria and yeasts increased on all carcasses during refrigerated storage. However, after 14 d of storage, significantly fewer psychrotrophic bacteria and yeasts were recovered from carcasses sprayed with EO water than from carcasses sprayed with tap or chlorinated water, and significantly fewer microorganisms were recovered from carcasses sprayed with chlorinated water than from carcasses sprayed with tap water. Pseudomonas spp. and Candida spp. were the primary microbial isolates recovered from the broiler carcasses. Findings from the present study indicate that EO water can effectively be used in inside-outside bird washers to decrease the population of spoilage bacteria and yeasts on processed broiler carcasses.

Microbiological impact of spray washing broiler carcasses using different chlorine concentrations and water temperatures.

A study was conducted to investigate the microbiological impact of spray washing broiler carcasses with chlorinated water (0 or 50 ppm) at different temperatures (21.1, 43.3, or 54.4 degrees C). A whole carcass rinse (WCR) was performed on each carcass before (control) and after spray washing (final). After the control WCR, carcasses were inoculated with 0.1 g of cecal material containing 2 x 10(5) cells per gram of Campylobacter and 2 x 10(5) cells per gram of nalidixic acid-resistant Salmonella. Carcasses were held at room temperature for 12 min before washing in an inside-outside bird washer (80 psi for 5 s). Chlorine level and water temperature had no effect on total aerobic bacteria, Escherichia coli, or Campylobacter numbers recovered from the final WCR. Levels of bacteria found on carcasses before and after washing were 4.6, 3.6, and 3.5 log10 cfu/mL rinse for total aerobic bacteria, E. coli, and Campylobacter, respectively. Average counts for nalidixic acid-resistant Salmonella after washing were 3.1 log10 cfu/ mL rinse irrespective of water temperature or chlorine level (P < 0.05). In addition, chlorine level and water temperature had no effect on the breast skin color, with average values of L* = 66.6; a* = -0.09; b* = -0.05 (P < 0.05). Under the conditions outlined in the present study, adding chlorine and/or elevating the water temperature during spray washing in an inside-outside bird washer did not enhance the removal of bacteria from broiler carcasses and had no effect on carcass skin color.

Bacteria recovery from genetically feathered and featherless broiler carcasses after immersion chilling.

Feathered and featherless (scaleless) sibling broilers were reared and processed together to evaluate the influence of feathers and feather follicles on carcass bacteria recovery after chilling. In each experiment, broilers were inoculated 1 wk prior to processing by oral gavage with a suspension of salmonellae or Campylobacter at 106 cells/mL. Broilers were stunned and bled, and carcasses were single-tank or triple-tank scalded, defeathered, eviscerated, and washed. Carcasses were chilled for 45 min in ice and water immersion chillers with or without 20 mg of chlorine/L added. Postchill carcass rinsates were evaluated for Escherichia coli, coliforms, total aerobes, and salmonellae or Campylobacter. Following processing and immersion chilling, genetically featherless carcasses had slightly higher counts (by log10 0.35 cfu/100 mL of carcass rinsate) for E. coli, coliforms, and total aerobes than feathered carcasses. However, there were no significant differences in the prevalence of salmonellae (25%) or Campylobacter (93%) between feathered and featherless carcasses. Recovery of E. coli, coliforms, and total aerobic bacteria were lower for carcasses that were single-tank scalded, and following enrichment, salmonellae were recovered from fewer carcasses subjected to the single-tank (71%) than triple-tank (86%) scalding. Addition of chlorine to chiller water significantly decreased carcass bacteria recovery (by log10 0.43 cfu/100 mL of carcass rinsate) for E. coli, coliforms, total aerobes, and Campylobacter but did not affect salmonellae recovery. The presence of feathers and feather follicles during processing and immersion chilling appears to have minimal influence on the recovery of salmonellae or Campylobacter from carcasses sampled after immersion chilling.

Recovery of Salmonella from commercial shell eggs by shell rinse and shell crush methodologies.

Salmonella is the most important human pathogen associated with shell eggs. Salmonella Enteritidis is the serotype most often implicated in outbreaks, although other serotypes have been recovered from eggs and from the commercial shell egg washing environment. Many sample methods are used to recover microorganisms from eggshells and membranes. A shell rinse and modified shell-and-membrane crush method for recovery of Salmonella were compared. Eggs were collected from 3 commercial shell-washing facilities (X, Y, and Z) during 3 visits. Twelve eggs were collected from each of 10 to 12 locations along the egg processing chain. After being transported back to the laboratory, each egg was sampled first by a shell rinse method and then by a shell crush method. For each technique (rinse or crush), 2 pools of 5 eggs per location sampled were selectively enriched for the recovery of Salmonella. Presumptive samples positive for Salmonella were confirmed serologically. Overall, there were 10.1% (40/396) Salmonella-positive pooled samples. Salmonella were recovered by the shell rinse and shell crush techniques (4.8 vs. 5.3%, respectively). Plant X yielded 21.5% Salmonella positives, whereas less than 5% of samples from plants Y and Z were found to be contaminated with the organism (4.2 and 4.5%, respectively). Salmonella was recovered more often from unwashed eggs (15.8%) than from washed eggs (8.3%). For some eggs, Salmonella was only recovered by one of the methods. Use of both approaches in the same experiment increased sampling sensitivity, although in most cases, crushing provided more sensitive Salmonella recovery.

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.

Carbohydrate-based cocktails that decrease the population of Salmonella and Campylobacter in the crop of broiler chickens subjected to feed withdrawal.

The efficacy of various carbohydrate-based cocktails in reducing the number of enteropathogens in the crops of broilers subjected to feed withdrawal was examined. Market-aged broilers that had been orally challenged with Salmonella typhimurium were provided the cocktails during a 12-h feed withdrawal. After feed withdrawal, the broilers were processed, and their crops were aseptically removed and weighed. Crops were then blended in distilled water, and the pH of the suspensions was measured electronically. Populations of S. typhimurium, Campylobacter, and lactic acid bacteria in the crop suspensions were enumerated. Findings indicated that significantly fewer S. typhimurium and Campylobacter were recovered from the crops of broilers that had been provided cocktails supplemented with sucrose than from the (Key words: crop, carbohydrate, feed crops of broilers provided cocktails supplemented with equal concentrations (wt/vol) of glucose. Furthermore, significantly fewer S. typhimurium were recovered from the crops of broilers provided cocktails supplemented with 2 to 10% sucrose than from the crops of broilers provided water or cocktails that were not supplemented with carbohydrates. The pH of the crop contents of broilers provided carbohydrate cocktails were lower than the pH of the crops of broilers provided water or cocktails that were not supplemented with carbohydrates. Consumption of the cocktails did not produce significant changes in the crop weights. Findings indicate that altering the composition of carbohydrate-based cocktails provided to broilers during feed withdrawal may affect the efficacy of cocktails in reducing the number of enteropathogens recovered from the crops of broilers.

Reduction of Salmonella in the crop of broiler chickens subjected to feed withdrawal.

Broilers were challenged with 10(9) Salmonella typhimurium and then were provided a glucose-based cocktail supplemented with 0 to 15% glucose during feed withdrawal in battery cages or in pens on litter. After feed withdrawal, broilers were processed, and their crops were aseptically removed and weighed. Crops were then stomached in distilled water, and the pH of the suspension was measured electronically. Salmonella typhimurium, Enterobacteriaceae, and lactic acid bacteria in the crop suspensions were enumerated on the appropriate bacteriological medium. Findings indicated that fewer S. typhimurium and other Enterobacteriaceae were recovered from the crops of broilers provided the cocktail supplemented with 7.5% glucose than from the crops of broilers provided either water or cocktails supplemented with lower or higher concentrations of glucose. Inhibition of the growth of S. typhimurium and other Enterobacteriaceae in the crops of broilers provided the cocktail supplemented with 7.5% glucose was generally associated with increased growth of lactic acid bacteria and decreased crop pH. Providing the cocktail to broilers before shipping to processing plants may reduce the number of food-borne pathogens that poultry carry into processing plants.

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.

Use of oleic acid to reduce the population of the bacterial flora of poultry skin.

The effect of oleic acid on native bacterial flora of poultry skin was examined. Skin from commercial broiler carcasses was washed once or twice in solutions of 0, 2, 4, 6, 8, or 10% (wt/vol) oleic acid and rinsed in peptone water. Aerobic bacteria, Enterobacteriaceae, Campylobacter, and enterococci in the rinsates were enumerated. Significantly fewer aerobic bacteria, Enterobacteriaceae, Campylobacter, and enterococci were recovered from rinsates of skin washed in oleic acid than from control samples. Additionally, fewer bacteria were recovered from rinsates of skin washed in higher concentrations of oleic acid than from skin washed in lower concentrations of the fatty acid. In most cases, there was no significant difference in the number of bacteria recovered from rinsates of skin washed once or twice in solutions of oleic acid. Washing skin samples twice in 10% solutions of oleic acid significantly reduced the number of aerobic bacteria, Enterobacteriaceae, Campylobacter, and enterococci that remained attached to the skin. Campylobacter sp., Enterococcus faecalis, and Listeria monocytogenes isolates possessed the least resistance to the antibacterial activity of oleic acid in vitro, while Escherichia coli and Pseudomonas aeruginosa showed higher resistance. Enterobacter cloacae, Staphylococcus lentus, and Salmonella Typhimurium had the greatest resistance to the antibacterial activity of oleic acid. Findings indicate that oleic acid reduces the number of bacteria on the skin of processed broilers and that the fatty acid is bactericidal to several spoilage and pathogenic bacteria associated with poultry.

Physical, chemical, and microbiological changes in the ceca of broiler chickens subjected to incremental feed withdrawal.

Trials were conducted to determine the effect of feed withdrawal on the weight, pH, native bacterial flora, and the persistence of Salmonella typhimurium in the ceca of market-age broilers. Broilers were provided medicated or unmedicated feed and then were subjected to feed withdrawal for 0 to 24 h in transportation crates or on litter. After feed withdrawal, broilers were stunned, bled, scalded, and picked. One cecum from each bird was aseptically removed and weighed. The cecum was then blended in 20 mL of distilled water, and the pH of the blended suspension was measured. The number of total aerobes, Enterobacteriaceae, S. typhimurium, and lactic acid bacteria in the suspension were enumerated on the appropriate bacteriological media. Results indicated that up to 24 h of feed withdrawal produced no significant change in cecal weight and that cecal pH varied by up to 0.3 units during feed withdrawal. There were significant increases in the population of Enterobacteriaceae during feed withdrawal in Trials 2 and 3, and there was a significant increase in the population of cecal aerobes in Trial 3. Feed withdrawal produced significant decreases in the population of lactic acid bacteria in all trials, but no significant change in the population of S. typhimurium occurred during feed withdrawal. There were no significant differences in cecal weight, pH, native bacteria populations, or S. typhimurium populations between broilers that were subjected to feed withdrawal on litter or in crates. Findings indicate that feed withdrawal does not always effectively evacuate the contents of the ceca and that the ceca of broilers subjected to feed withdrawal can remain a source of foodborne bacterial pathogens.