Comparison of Neck Skin Excision and Whole Carcass Rinse Sampling Methods for Microbiological Evaluation of Broiler Carcasses before and after Immersion Chilling

Sampling protocols for detecting Salmonella on poultry differ among various countries. In the United States, the U.S. Department of Agriculture Food Safety and Inspection Service dictates that whole broiler carcasses should be rinsed with 400 ml of 1% buffered peptone water, whereas in the European Union 25-g samples composed of neck skin from three carcasses are evaluated. The purpose of this study was to evaluate a whole carcass rinse (WCR) and a neck skin excision (NS) procedure for Salmonella and Escherichia coli isolation from the same broiler carcass. Carcasses were obtained from three broiler processing plants. The skin around the neck area was aseptically removed and bagged separately from the carcass, and microbiological analysis was performed. The corresponding carcass was bagged and a WCR sample was evaluated. No significant difference (alpha <= 0.05) in Salmonella prevalence was found between the samples processed by the two methods, but both procedures produced many false-negative Salmonella results. Prechill, 37% (66 carcasses), 28% (50 carcasses), and 51% (91 carcasses) of the 180 carcasses examined were positive for Salmonella by WCR, NS, and both procedures combined, respectively. Postchill, 3% (5 carcasses), 7% (12 carcasses), and 10% (17 carcasses) of the 177 carcasses examined were positive for Salmonella by the WCR, NS, and combination of both procedures, respectively. Prechill, E. coli plus coliform counts were 3.0 and 2.6 log CFU/ml by the WCR and NS methods, respectively. Postchill. E. coli plus coliform counts were 1.7 and 1.4 log CFU/ml by the WCR and NS methods, respectively.

Microbiological Evaluation of Chicken Carcasses in an Immersion Chilling System with Water Renewal at 8 and 16 Hours

Since 2004, Brazil has been the leading exporter of chicken. Because of the importance of this sector in the Brazilian economy, food safety must be ensured by control and monitoring of the production stages susceptible to contamination, such as the chilling process. The goal of this study was to evaluate changes in microbial levels on chicken carcasses and in chilling water after immersion in a chilling system for 8 and 16 h during commercial processing. An objective of the study was to encourage discussion regarding the Brazilian Ministry of Agriculture Livestock and Food Supply regulation that requires chicken processors to completely empty, clean, and disinfect each tank of the chilling system after every 8-h shift. Before and after immersion carcasses were collected and analyzed for mesophilic bacteria, Enterobacteriaceae, conforms, and Escherichia coli. Samples of water from the chilling system were also analyzed for residual free chlorine. The results do not support required emptying of the chiller tank after 8 h; these tanks could be emptied after 16 h. The results for all carcasses tested at the 8- and 16-h time points indicated no significant differences in the microbiological indicators evaluated. These data provide both technical and scientific support for discussing changes in federal law regarding the management of immersion chilling water systems used as part of the poultry processing line.

Evaluation of three sampling methods for the microbiological analysis of broiler carcasses after immersion chilling

Countries have different official programs and implement different sampling methods for the detection of Salmonella on poultry carcasses. In Brazil, a 25-g sample of skin and muscle excision (SME) from the wings, neck, and pericloacal parts is used; in the European Union (EU), a 25-g sample of neck skin (NSE) is used; and, in the United States, the whole carcass is rinsed with 400 ml of diluent (WCR). In the present study, these methods were evaluated to compare Salmonella occurrence and counts of hygiene indicator microorganisms (Escherichia coli, Enterobacteriaceae, and total viable count of aerobic mesophilic bacteria) using different carcasses from the same flock and also using different analytical units taken from the same carcass. Eighty flocks, with four broiler carcasses from each, were included in this study; three broilers were sampled according to protocols from Brazil, the EU, and the United States, and the last one by all three methods. SME, NSE, and WCR provided equivalent results (P > 0.05) for Salmonella detection on broiler carcasses when using different carcasses from the same flock and when using the same carcass. The predominant serovar was Salmonella Enteritidis. For the enumeration of hygiene indicator microorganisms, WRC provided higher counts than SME or NSE (P < 0.05), when using both the same or different carcasses. Therefore, it is possible to directly compare Salmonella results in poultry carcasses when using the methods recommended by the legislative bodies of Brazil, the United States, and the EU. However, WCR provides the best results for hygiene indicator microorganisms. Copyright © International Association for Food Protection.

Comparison of microbial load in immersion chilling water and poultry carcasses after 8, 16 and 24 working hours

As atividades dos estabelecimentos de abate de frangos são conhecidas por utilizarem grandes volumes de água durante seus processos, principalmente no processo de resfriamento das carcaças de frangos. Parte desse volume utilizado se faz necessário, em cumprimento à legislação que determina que cada tanque do sistema de pré-resfriadores contínuos por imersão deve ser completamente esvaziado, limpo e desinfetado no final de cada período de trabalho (oito horas). O objetivo deste estudo foi comparar a carga microbiana das águas do sistema de resfriamento e das carcaças de frango ao final de oito, dezesseis e vinte e quatro horas de trabalho do abatedouro, para possível redução do número de vezes do completo esvaziamento dos tanques do sistema de resfriamento. Foram avaliadas, por meio de métodos convencionais microbiológicos e físico-químicos, amostras da água de abastecimento (n=69), visando a evitar possível interferência nas contagens das águas do sistema de resfriamento, amostras de carcaças de frango antes (n=345) e após (n=345) sua passagem pelo sistema de resfriamento e amostras de águas do último estágio do sistema de resfriamento de carcaças (n=69). Os resultados obtidos demonstraram que não houve diferença significativa na carga microbiana das amostras entre as três jornadas de trabalho do estabelecimento, sugerindo que a redução é segura, diminuindo assim o volume de águas residuais e seu impacto no meio ambiente, bem como melhorando o uso racional do tempo de processamento.

Extrinsic factors affecting water absorption in chilling of broiler chicken carcasses

Brazil occupies an outstanding position as a producer and exporter of chicken meat, and the maintenance and expansion of this position require a constant evolution, especially in variables which determine quality. An important quality parameter of poultry meat is the amount of water absorbed by the carcass during processing. In Brazil, carcasses chilling is done by immersion in chilled water. In this process, the carcass is rehydrated and the water lost during transport and initial operations is replaced. At this stage, some care is needed to prevent the absorption of water upper than the level allowed by Brazilian law. This project aimed to evaluate extrinsic factors that can influence the absorption of water by the chicken meat. For this, 144 Cobb chickens divided into 24 groups of six birds were used. At 42 days of age, one chicken of each group, with weight ranging up to 10% more or less from the average of the group, was slaughtered in an experimental pilot scale abattoir where slaughter procedures were conducted under strictly controlled conditions. The chilling procedure was performed following a completely randomized design with factorial arrangement 3x2, where the factors were: three temperatures in the first section of the chilling system (4, 10 and 16ºC) and two degrees of water hardness (hard and soft water), with six treatments and four replications. Brazilian law provides that the water temperature in the first section of the chiller must not be higher than 16ºC, and the length of the carcasses in this section shall not exceed 30 minutes. All carcasses remained in the first section of the chiller for 30 minutes and then were transferred to another tank with water at 4ºC, remaining there until reaching 7ºC. The carcasses were weighed before and after chilling, to evaluate the percentage of water absorbed. The water absorption was influenced by the initial temperature of the water in the chiller and by the water hardness. When initially immersed in water at 4ºC, carcasses water absorption averaged 2.70%, a significantly lower absorption than the values found for the carcasses that were initially immersed in water at 16ºC, 3.83% (p<0.05). The carcasses immersed in water at 10ºC had mean water absorption of 3.66%, not differing from the means observed in the other two treatments (p>0.05). In hard water, the average water absorption was 2.46% and, in soft water, 4.33% (p<0.05). In all treatments, the water absorption did not exceed the limit established by Brazilian legislation, which is a maximum of 8%. This information is important to control the absorption of water by carcasses in chicken meat processing, preventing consumers from being harmed.

Comparison of Ozone and Chlorine in Low Concentrations as Sanitizing Agents of Chicken Carcasses in the Water Immersion Chiller

The aim of this study was to investigate the effects of the use of chlorine or ozone as sanitizing agents in the water of chicken immersion chilling, using the residual levels usually applied in Brazil (1.5 ppm), comparing the effects of these treatments on the microbiological, physicochemical, and sensory characteristics of carcasses. Chicken carcasses were chilled in water (4 degrees C) with similar residual levels of ozone and chlorine until reaching temperatures below 7 degrees C (around 45 min). The stability of carcasses was assessed during 15 days of storage at 2 +/- 1 degrees C. Microbiological, surface color (L*, a*, b* parameters), pH value, lipid oxidation (thiobarbituric acid reactive substances index), and sensory evaluation (on a 9-point hedonic scale for odor and appearance) analyses were carried out. The presence of Salmonella was not detected, coagulase-positive staphylococci counts were below 10(2) CFU/ml of rinse fluid, and Escherichia coil and total coliform counts were below 10(5) CFU/ml of rinse fluid until the end of the storage period for both treatments. Psychrotrophic microorganism counts did not differ (P > 0.05) between chlorine and ozone treatments, and both values were near 10(9) CFU/ml of rinse fluid after 15 days at 4 +/- 1 degrees C. pH values did not differ between treatments (P > 0.05) or during the storage period (P > 0.05). In addition, neither chlorine nor ozone treatment showed differences (P > 0.05) in the lipid oxidation of carcasses; however, the thiobarbituric acid reactive substances index of both treatments increased (P <= 0.05) during the storage period, reaching values of approximately 0.68 mg of malonaldehyde per kg. Samples from both treatments did not differ (P > 0.05) in their acceptance scores for odor and overall appearance, but in the evaluation of color, ozone showed an acceptance score significantly higher (P <= 0.05) than that for the chlorine treatment. In general, under the conditions tested, ozone showed results similar to the results for chlorine in the disinfection of chicken carcasses in the immersion chilling, which may indicate its use as a substitute for chlorine in poultry slaughterhouses.

Mapping the carriage of flaA-restriction fragment length polymorphism Campylobacter genotypes on poultry carcasses through the processing chain and comparison to clinical isolates

Poultry are considered a major source for campylobacteriosis in humans. A total of 1866 Campylobacter spp. isolates collected through the poultry processing chain were typed using flaA-restriction fragment length polymorphism to measure the impact of processing on the genotypes present. Temporally related human clinical isolates (n = 497) were also typed. Isolates were obtained from whole chicken carcass rinses of chickens collected before scalding, after scalding, before immersion chilling, after immersion chilling and after packaging as well as from individual caecal samples. A total of 32 genotypes comprising at least four isolates each were recognised. Simpson's Index of Diversity (D) was calculated for each sampling site within each flock, for each flock as a whole and for the clinical isolates. From caecal collection to after packaging samples the D value did not change in two flocks, decreased in one flock and increased in the fourth flock. Dominant genotypes occurred in each flock but their constitutive percentages changed through processing. There were 23 overlapping genotypes between clinical and chicken isolates. The diversity of Campylobacter is flock dependant and may alter through processing. This study confirms that poultry are a source of campylobacteriosis in the Australian population although other sources may contribute.

Avaliação de substâncias desinfetantes utilizadas na água de tanques de pré-resfriamento de abatedouro avícola

Pós-graduação em Medicina Veterinária - FCAV

Avaliação microbiológica de carcaças de frango e água em um sistema de pré-resfriamento por imersão em 8 horas e 16 horas

Pós-graduação em Medicina Veterinária - FMVZ

Comparação da carga microbiana e mapeamento de salmonelas (PCR) em águas de pré-resfriamento por imersão e carcaças de frangos em diferentes jornadas de trabalho

Pós-graduação em Microbiologia Agropecuária - FCAV

English language study abroad program : an investigation of Hong Kong pre-service teachers’ experiences of a language immersion program

There has been minimal research focused on short-term study abroad language immersion programs, in particular, with home-stay families. The importance of authentic intercultural experience is increasingly clear and was acknowledged as central to the process of language learning (Liddicoat, 2004). In Hong Kong, education programs for pre-service language teachers have significantly emphasised language and intercultural training through short-term study abroad, and these short overseas language immersion courses have become a compulsory component for teacher training (Bodycott & Crew, 2001) in the last decade. This study aims to investigate eight Hong Kong pre-service teachers’ and their home-stay families’ experiences of a short-term (two months) language immersion program in Australia. The focus is on listening to commentaries concerning the development of communicative competence, intercultural competence and professional growth during the out-of-class study abroad experience. The conceptual framework adopted in this study views language and intercultural learning from social constructivist perspectives. Central to this framing is the notion that the internalisation of higher mental functions involves the transfer from the inter-psychological to the intra-psychological plane, that is, a progression process from the socially supported to individually controlled performance. From this perspective, language serves as a way to communicate about, and in relation to, actions and experience. Three research questions were addressed and studied through qualitative methodology. 1. How do the pre-service teachers and their home-stay families perceive the out-of-class component of the program in terms of opportunities for the development of language proficiency and communicative competence? 2. How do the pre-service teachers and their home-stay families perceive the out-of-class component of the program in terms of the development of intercultural competence? 3. How do the pre-service teachers and home-stay families perceive the outof- class component of the program in terms of teachers’ professional growth? Data were generated from multiple data collection methods and analysed through thematic analysis from both a “bottom up” and “top down” approach. The study showed that the pre-service teachers perceived that the immersion program influenced, to varying degrees, their language proficiency, communication and intercultural awareness, as well as their self-awareness and professional growth. These pre-service teachers believed that effective language learning centres on active engagement in the target language community. A mismatch between the views and evaluations of the two groups – the pre-service teachers and the home-stay family members – provides some evidence of misalignments in terms of expectations and perceptions of each other’s roles and responsibilities. The study has highlighted challenges encountered, and provided suggestions for ways of meeting these challenges. The inclusion in the study of the home-stay families’ perceptions and commentaries provided insights, which can inform program development. There is clearly further work to be done in terms of predeparture orientation and preparation, not only for the main participants themselves, the students, but also for the host families.

Effect of cold water immersion on repeated cycling performance and limb blood flow

The purpose of the present study was to compare the effects of cold water immersion (CWI) and active recovery (ACT) on resting limb blood flow, rectal temperature and repeated cycling performance in the heat. Ten subjects completed two testing sessions separated by 1 week; each trial consisted of an initial all-out 35-min exercise bout, one of two 15-min recovery interventions (randomised: CWI or ACT), followed by a 40-min passive recovery period before repeating the 35-min exercise bout. Performance was measured as the change in total work completed during the exercise bouts. Resting limb blood flow, heart rate, rectal temperature and blood lactate were recorded throughout the testing sessions. There was a significant decline in performance after ACT (mean (SD) −1.81% (1.05%)) compared with CWI where performance remained unchanged (0.10% (0.71%)). Rectal temperature was reduced after CWI (36.8°C (1.0°C)) compared with ACT (38.3°C (0.4°C)), as was blood flow to the arms (CWI 3.64 (1.47) ml/100 ml/min; ACT 16.85 (3.57) ml/100 ml/min) and legs (CW 4.83 (2.49) ml/100 ml/min; ACT 4.83 (2.49) ml/100 ml/min). Leg blood flow at the end of the second exercise bout was not different between the active (15.25 (4.33) ml/100 ml/min) and cold trials (14.99 (4.96) ml/100 ml/min), whereas rectal temperature (CWI 38.1°C (0.3°C); ACT 38.8°C (0.2°C)) and arm blood flow (CWI 20.55 (3.78) ml/100 ml/min; ACT 23.83 (5.32) ml/100 ml/min) remained depressed until the end of the cold trial. These findings indicate that CWI is an effective intervention for maintaining repeat cycling performance in the heat and this performance benefit is associated with alterations in core temperature and limb blood flow.

Effects of cold water immersion on knee joint position sense in healthy volunteers

The purpose of this study was to determine the effects of cryotherapy, in the form of cold water immersion, on knee joint position sense. Fourteen healthy volunteers, with no previous knee injury or pre-existing clinical condition, participated in this randomized cross-over trial. The intervention consisted of a 30-min immersion, to the level of the umbilicus, in either cold (14 ± 1°C) or tepid water(28 ± 1°C). Approximately one week later, in a randomized fashion, the volunteers completed the remaining immersion. Active ipsilateral limb repositioning sense of the right knee was measured, using weight-bearing and non-weight bearing assessments, employing video-recorded 3D motion analysis. These assessments were conducted immediately before and after a cold and tepid water immersion. No significant differences were found between treatments for the absolute (P = 0.29), relative (P = 0.21) or variable error (P = 0.86). The average effect size of the outcome measures was modest (range –0.49 to 0.9) and all the associated 95% confidence intervals for these effect sizes crossed zero. These results indicate that there is no evidence of an enhanced risk of injury, following a return to sporting activity, after cold water.

Consecutive days of cold water immersion: effects on cycling performance and heart rate variability.

We investigated performance and heart rate (HR) variability (HRV) over consecutive days of cycling with post-exercise cold water immersion (CWI) or passive recovery (PAS). In a crossover design, 11 cyclists completed two separate 3-day training blocks (120 min cycling per day, 66 maximal sprints, 9 min time trialling [TT]), followed by 2 days of recovery-based training. The cyclists recovered from each training session by standing in cold water (10 °C) or at room temperature (27 °C) for 5 min. Mean power for sprints, total TT work and HR were assessed during each session. Resting vagal-HRV (natural logarithm of square-root of mean squared differences of successive R-R intervals; ln rMSSD) was assessed after exercise, after the recovery intervention, during sleep and upon waking. CWI allowed better maintenance of mean sprint power (between-trial difference [90 % confidence limits] +12.4 % [5.9; 18.9]), cadence (+2.0 % [0.6; 3.5]), and mean HR during exercise (+1.6 % [0.0; 3.2]) compared with PAS. ln rMSSD immediately following CWI was higher (+144 % [92; 211]) compared with PAS. There was no difference between the trials in TT performance (-0.2 % [-3.5; 3.0]) or waking ln rMSSD (-1.2 % [-5.9; 3.4]). CWI helps to maintain sprint performance during consecutive days of training, whereas its effects on vagal-HRV vary over time and depend on prior exercise intensity.

Effect of cold water immersion after exercise in the heat on muscle function, body temperatures, and vessel diameter

Cold water immersion (CWI) is a popular recovery modality, but actual physiological responses to CWI after exercise in the heat have not been well documented. The purpose of this study was to examine effects of 20-min CWI (14 degrees C) on neuromuscular function, rectal (T(re)) and skin temperature (T(sk)), and femoral venous diameter after exercise in the heat. Ten well-trained male cyclists completed two bouts of exercise consisting of 90-min cycling at a constant power output (216+/-12W) followed by a 16.1km time trial (TT) in the heat (32 degrees C). Twenty-five minutes post-TT, participants were assigned to either CWI or control (CON) recovery conditions in a counterbalanced order. T(re) and T(sk) were recorded continuously, and maximal voluntary isometric contraction torque of the knee extensors (MVIC), MVIC with superimposed electrical stimulation (SMVIC), and femoral venous diameters were measured prior to exercise, 0, 45, and 90min post-TT. T(re) was significantly lower in CWI beginning 50min post-TT compared with CON, and T(sk) was significantly lower in CWI beginning 25min post-TT compared with CON. Decreases in MVIC, and SMVIC torque after the TT were significantly greater for CWI compared with CON; differences persisted 90min post-TT. Femoral vein diameter was approximately 9% smaller for CWI compared with CON at 45min post-TT. These results suggest that CWI decreases T(re), but has a negative effect on neuromuscular function.