Assessing the microbiomes of scalder and chiller tank waters throughout a typical commercial poultry processing day.

The commercial poultry processing environment plays a significant role in reducing foodborne pathogens and spoilage organisms from poultry products prior to being supplied to consumers. While understanding the microbiological quality of these products is essential, little is known about the microbiota of processing water tanks within the processing plant. Therefore, the goal of this study was to assess the microbiomes of the scalder and chiller tanks during a typical commercial processing d, and determine how bacterial populations, including foodborne pathogens and spoilage organisms, change during the processing day in relation to the bacterial communities as a whole. Additionally, considering this is the first microbiomic analysis of processing tank waters, 2 water sampling methods also were compared. Results of this study show that Proteobacteria and Firmicutes represented over half of the sequences recovered from both tanks at the phylum level, but the microbiomic profiles needed to be analyzed at the genus level to observe more dynamic population shifts. Bacteria known to predominate in the live production environment were found to increase in the scalder tank and gram negative spoilage-related bacteria were found to decrease in the chiller tank throughout the processing day. Directly sampling the scalder water, as compared to analyzing filtered samples, resulted in significantly different microbiomic profiles dominated by Anoxybacillus species. While no sequences related to major foodborne pathogens were found, further sampling collection and processing optimization should provide researchers and the poultry industry a new tool to understand the ecological role of spoilage and pathogenic bacteria within processing tank waters.

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.

The effects of commercial cool water washing of shell eggs on Haugh unit, vitelline membrane strength, aerobic microorganisms, and fungi.

Current egg washing practices use wash water temperatures averaging 49 degrees C and have been found to increase internal egg temperature by 6.7 to 7.8 degrees C. These high temperatures create a more optimal environment for bacterial growth, including Salmonella Enteritidis if it is present. Salmonella Enteritidis is the most common human pathogen associated with shell eggs and egg products. Its growth is inhibited at temperatures of 7.2 degrees C and below. The objective of this study was to determine if commercially washing eggs in cool water would aid in quickly reducing internal egg temperature, preserving interior egg quality, and slowing microbial growth. During 3 consecutive days, eggs were washed using 4 dual-tank wash water temperature schemes (HH = 49 degrees C, 49 degrees C; HC = 49 degrees C, 24 degrees C; CC = 24 degrees C, 24 degrees C; CH = 24 degrees C, 49 degrees C) at 2 commercial processing facilities. A 10-wk storage study followed, in which vitelline membrane strength, Haugh unit, and aerobic microorganisms and fungi (yeasts and molds) were monitored weekly. As storage time progressed, average Haugh unit values declined 14.8%, the average force required to rupture the vitelline membrane decreased 20.6%, average numbers of bacteria present on shell surfaces decreased 11.3%, and bacteria present in egg contents increased 39.5% during storage. Wash water temperature did not significantly affect Haugh unit values, vitelline membrane strength, or the numbers of aerobic microorganisms and fungi within the shell matrices of processed eggs. Results of this study indicate that incorporating cool water into commercial shell egg processing, while maintaining a pH of 10 to 12, lowers postprocessing egg temperatures and allows for more rapid cooling, without causing a decline in egg quality or increasing the presence of aerobic microorganisms and fungi for approximately 5 wk postprocessing.

Differential effects of 7-OH-DPAT on the development of behavioral sensitization to apomorphine and cocaine.

The primary objective of this study was to determine whether concurrent treatments with a low dose of the dopamine D(3)-preferring receptor agonist 7-OH-DPAT would attenuate the development of behavioral sensitization to the indirect dopamine receptor agonist, cocaine, or the direct dopamine receptor agonist, apomorphine. In two experiments, male Wistar rats (250-350 g) were given seven daily injections of 7-OH-DPAT (0.05 mg/kg sc) or vehicle in combination with either cocaine (15 mg/kg ip), apomorphine (1.0 mg/kg sc), or vehicle. After the injections, the rats were tested for activity in photocell arenas for 40 min, and three measures of motor behavior (distance traveled, rearing, and stereotypy) were recorded at 10-min intervals. A total of 24 h after the last preexposure session, all rats were given a challenge injection of either cocaine (10.0 mg/kg ip, Experiment 1) or apomorphine (1.0 mg/kg sc, Experiment 2) and tested for activity. Major findings were as follows: (a) 7-OH-DPAT treatments alone suppressed all measures of locomotor activity and did not affect subsequent behavioral sensitivity to either cocaine or apomorphine; (b) cocaine treatments acutely increased all measures of activity, and repeated treatments produced behavioral sensitization to the horizontal locomotor-activating effects of cocaine; (c) apomorphine treatments alone increased horizontal activity and stereotypy but completely abolished rearing behavior; (d) like cocaine, repeated treatments with apomorphine induced behavioral sensitization; (e) concurrent treatments of 7-OH-DPAT with cocaine acutely attenuated cocaine-induced increases in motor behavior but enhanced the development of behavioral sensitization to cocaine; and (f) concurrent 7-OH-DPAT treatments did not significantly affect either the acute or chronic effects of apomorphine. It is evident from these results that concurrent treatment with 7-OH-DPAT does not block the development of behavioral sensitization to either cocaine or apomorphine. Moreover, the differential acute and chronic effects of 7-OH-DPAT on cocaine- and apomorphine-induced hyperactivity appear to be mediated by dopamine autoreceptor stimulation.

Ketocyclazocine, a kappa-opioid receptor agonist, and control of intestinal myoelectric activity in dogs.

The role of kappa-opioid receptors in the control of fed and fasted myoelectrical activity of the stomach and small intestine was studied in conscious dogs implanted with bipolar silver electrodes. In fasted dogs, migrating myoelectric complex (MMC) cycle times were 105 +/- 14 min in the duodenum. Administration of ketocyclazocine (1 mg/kg iv) inhibited contractile activity, blocked migration of distally propagating MMCs, and increased the MMC cycle time to 246 +/- 56 min (P less than 0.0005). Pretreatment with naloxone (2 mg/kg iv) 5 min before administration of ketocyclazocine (1 mg/kg iv) prevented the disruption by ketocyclazocine of the distally propagating MMC but did not completely antagonize the effect of ketocyclazocine on MMC cycle time. MMC cycle time was 102 +/- 14 min before naloxone plus ketocyclazocine administration and 138 +/- 22 min after administration (P less than 0.005). Although MMC cycle times were still significantly prolonged over control after naloxone plus ketocyclazocine, cycle times were significantly decreased compared with ketocyclazocine administration alone (P less than 0.005). Ketocyclazocine (1 mg/kg iv) completely inhibited the fed pattern of myoelectric activity for 74 +/- 26 min when administered 15 min after feeding. Bethanecol (2 mg sc)-initiated spike activity was not blocked by ketocyclazocine. These studies suggest that endogenous opioids and kappa-opioid receptors may play a role in the inhibition of gastric action potentials and small intestinal spiking activity.