DEVELOPMENT OF IMAGING TECHNOLOGY FOR FOOD SAFETY AND SECURITY
Location: Quality and Safety Assessment Research Unit
Title: INFLUENCE OF WATER PROVISION TO CHICKS PRIOR TO PLACEMENT ON PERFORMANCE ON INCIDENCE OF UNABSORBED YOLK SACS
Submitted to: Journal of Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 24, 2006
Publication Date: N/A
Interpretive Summary: After hatching, chicks are transferred to chick-baskets where they remain until placement in a grow-out house. Because there is no mechanism for providing water to chicks in these baskets, they may be held without water for 2 to 12 hours before arriving at the grow-out house. The time without water could be even longer if chicks are transported to other countries or hatched in other countries. This study was conducted for two reasons: 1) to evaluate a new device for delivering water to chicks in chick-baskets (Aqua Chick Tray®); and 2) to evaluate any performance benefits of water provision to chicks prior to placement. To accomplish the objectives of the study, commercial chicks were obtained from a local hatchery and held for either 24 or 48 hours in chick-baskets with or without access to water. After holding, chicks were distributed into floor pens in a grow-out house and given unlimited access to feed and water. At 6 week of age, broilers were processed, and intestines were evaluated for presence or absence of an unabsorbed yolk sac (an indication of feed utilization) and intestinal breaking strength (an indication of intestinal integrity). Body weight at placement was greater for chicks provided access to water (2 to 6 grams/chick); however, after one week, this body weight difference disappeared. Providing water to chicks prior to placement had no affect on mortality, overall feed consumption, or final body weight. The incidence of unabsorbed yolk sacs ranged from 15 to 28%, and chick water provision had no effect on the incidence of unabsorbed yolk sacs or intestinal breaking strength. Data from the present study demonstrates that providing chicks with water prior to placement does not measurably influence performance, intestinal breaking strength, or the incidence of unabsorbed yolk sacs through 6 week of age.
In a previous study, the levels of bacteria recovered from broiler carcass halves after immersion chilling in a low volume of water (2.1 L/kg) were greater than the levels of bacteria recovered from halves after immersion chilling in a high volume of water (16.8 L/kg). A second study was conducted to determine if the recovery of bacteria from chilled broiler carcass halves would be different if a commercial immersion chilling volume was used (3.3 L/kg) compared to double that volume (6.7 L/kg). For this study, pre-chill 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 either 3.3 L/kg or 6.7 L/kg distilled water. Bags containing halves were submersed in a secondary chill tank containing approximately 150 L of an air-agitated ice-water mix (0.6°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 (APC), Escherichia coli (EC), Enterobacteriaceae (EN) and Campylobacter (CP). When the numbers of bacteria in the half-carcass rinses (HCR) were compared, counts recovered from halves chilled in 3.3 L/kg of water were the same as those recovered from the halves chilled with 6.7 L/kg of water (P > 0.05). Levels found in the HCR ranged from 4.0 to 4.2 log10 cfu/mL for APC, 3.3 to 3.5 log10 cfu/mL for EC, 3.6 to 3.8 log10 cfu/mL for EN and 2.4 to 2.6 log10 cfu/mL for CP. Data were also analyzed using a paired comparison t-test, and this analysis also showed that there was no difference (P > 0.05) in the numbers of APC, EC, EN or CP recovered from paired-halves chilled in different volumes of water. The present study shows that doubling the amount of water that is traditionally used during immersion chilling (6.7 L/kg) will not improve the removal of bacteria from the surfaces of chilled carcasses.
Key Words: Poultry, immersion chilling, carcass bacteria recovery, chiller water volume