Credit hours In-class work per week Practice per week Credits Duration Total 3 1 8 15 weeks hours. Objective This course is offered to graduate students registered in other postgraduate programs from ESALQ in master and doctoral level, in order to train them in planning, analysis of agronomic experiments and interpret the results of the obtained data. Content Review of general statistics. Random variation. Design of experiments.
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Influence of the cleaning system of conveyor belts on microbiological quality of poultry meat. Cortezi 1. Rossi 1. Balieiro 3. This study focused on assessing the microbiology of conveyor belts surfaces, cleaned or not with pressurized water, and verification of the influence of this process on the microbiological quality of poultry meat. For the chicken leg consisting of drumstick and thigh samples, no statistically significant differences were detected on counts of indicators of microorganisms on poultry legs composed by drumstick and thigh.
Only one sample of chicken leg was positive for presence of L. These results demonstrate that there is no need to use water for cleaning conveyor belts during processing, which allows a reduction on the use of potable water in poultry slaughterhouses without jeopardizing food safety and public health. The conveyor belts in cutting and deboning rooms in poultry slaughterhouses are used to allow hygienic conditions during meat processing.
The sanitation procedure through water sprinkles on conveyor belts surfaces is routinely performed in slaughterhouses as required by the Ordinance No. The use of water during cleaning aims to prevent the occurrence of cross-contamination among meat cuts. However, water also spreads microorganisms in processing environment Hamidi et al. According to Soares et al. However, its influence on the microbiological quality of poultry cuts was not evaluated.
Thus, this study was performed in order to better understand the influence of using water during transport on conveyor belts on the microbiological quality of poultry cuts, in order to verify the risks for public health. The indicator microorganisms are useful to evaluate the microbiological quality of food, providing information regarding food contamination degree and hygienic conditions during processing and storage Santos, According to Silva et al.
Another group used for evaluation of the hygienic condition of food is psychrotrophic microorganisms, which are responsible for food spoilage and modifications on sensory characteristics Carvalho et al. Nevertheless, the main indicators of hygiene-sanitary conditions of food are bacteria included in Enterobacteriaceae family, such as Escherichia coli Silva et al. The presence of Staphylococcus aureus in food indicates that contamination occurred through improper handling or inadequate cleaning of utensils and equipment Siqueira, Furthermore, bacteria belonging to Listeria genus are also involved in food contamination and outbreaks Franco e Landgraf, Among them, Listeria monocytogenes is considered as the most important pathogenic specie and its presence is reported at refrigerated environments e.
Considering these mentioned aspects, this study focused on assessing the microbiology of conveyor belts surfaces, cleaned or not with pressurized water, and verification of the influence of this process on the microbiological quality of poultry meat.
This study was approved by the Research Ethic Committee Thus, these carcasses are hung on hooks from an automatic cutting machine that cut carcasses as follow: breast meat, wings, sirloin and thighs with drumsticks.
Afterwards, these cuts are transported on a polyethylene conveyor belt 12 meters which moves clockwise and has a self-cleaning system that uses pressurized chlorinated water 0. This cleaning system of conveyor belts did not allow the direct contact of poultry cuts with the water. Mechanical cleaning and meat fragments removal were performed using stainless steel scrapers. A total of samples were collected during 10 distinct visits in the slaughterhouse.
During each visit, a set of 16 samples were collected as follow:. Dry conveyors belts 4 samples per collection : swab of the beginning of conveyor belt 1 sample , poultry cut transported on the beginning of conveyor belt 1 sample , swab of the end of conveyor belt 1 sample , and poultry cut processed transported on the end of conveyor belt 1 sample.
Wet conveyors belts 4 samples per collection : swab of the beginning of conveyor belt 1 sample , poultry cut transported on the beginning of conveyor belt 1 sample , swab of the end of conveyor belt 1 sample , and poultry cut processed transported on the end of conveyor belt 1 sample. The operational cleaning was performed in this industry when deboning was finished. Swabs were transferred to sterile Falcon tubes containing 10mL of 0. All samples were collected during deboning operation.
The rinse technique on sterile plastic bags was used for chicken leg samples Silva et al. The content of falcon tubes were transferred to Erlenmeyer flasks containing 90mL of 0. The samples of chicken cuts were weighed and 1mL of 0. Compendium…, The sampled area was divided by the volume of diluent used and the results were expressed as CFU cm For Staphylococcus spp.
Listeria spp. Aliquots of 25g of deboned chicken legs thigh and drumstick were added to mL of LEB. The samples were transferred to asterile polyethylene bag and processed in a stomacher for 1 minute. After this period, an aliquot of 0. The black, regular colonies, surrounded by dark halo esculin hydrolysis were considered as suspected for Listeria spp.
Those characteristic colonies of Listeria spp. Five characteristic colonies of Listeria spp. For those plates with count lower than five colonies, all colonies were selected. The biochemical characterization of L. The counts of microorganisms were converted to the base logarithm of the number of colony-forming units plus 1. The adopted model is presented in the Explanatory Note. Data on Listeria spp. The model used for Listeria spp. Table 1 presents the average counts of indicator microorganisms in samples collected at two different sites of the surface of conveyor belts beginning and end.
These results highlighted that the use of water probably influenced in the obtained results, not assuring an adequate cleaning of the conveyor belts surfaces. The fact that water spread microorganisms Hamidi et al. Our results disagree with those reported by Soares et al. However, the temperature of the water used in these experiments was not the same. These results demonstrate that the microbial contamination on the surface of conveyor belts can be higher when the water is used at room temperature.
In a previous study, Bersot et al. Furthermore, the water at every processing step can be a risk, requiring more attention to effective water management in the processing plan Hamidi et al.
However, there was no difference on the other groups of microorganisms. Thus, the sample collection site near or 12 meters from auto-cleaning system did not influence the microbiological contamination of poultry cuts. The results of indicator microorganisms mesophilic, psychrotrophic, Enterobacteriaceae and Staphylococcus spp.
The results of microbiological contamination thorough counting indicator microorganisms on poultry meat and areas of conveyor belts beginning and end were similar due to no detection of significant differences between chicken meat cuts conducted by dry or wet conveyor belts. Thus, the contact between poultry meat and the surfaces of conveyor belts wet or dry did not influence poultry meat contamination.
For samples collected at distinct times, only the populations of psychrotrophic microorganism were different. The population of psychrotrophic microorganisms in the beginning and end of the conveyor belts surfaces were higher on the end. However, this contamination did not influence the average count of psychrotrophic microorganisms on samples of poultry meat. No statistically significant difference was observed between both areas of the conveyor belts beginning and end where chicken legs samples were collected.
Table 3 shows the results of counts of Listeria spp. Under the conditions of this experiment, the use of no water on the conveyor belts provided a higher detection of this microorganism. These results could occurr due a reduction on the number of competitor flora because these microorganisms multiply under high-humidity condition. However, there was no significant difference on the counts of mesophilic and psychrotrophic microorganisms as shown in Table 1.
On the other hand, Listeria spp. The presence of Listeria spp. Furthermore, surfaces roughness of conveyor belts is an important factor that affects cleaning and sanitizing Chaturongkasumrit et al. Santos et al. These values are inferior to those obtained in the present study and probably this difference occurred due difference on sample size. The surface contaminated with Listeria spp. Cross-contamination often occurs when equipment and utensils such as cutting boards that are used during food processing are not properly cleaned Goh et al.
The control of Listeria spp. Regarding poultry cuts, no statistically significant differences were established, but the samples included in this study presented a high prevalence of Listeria spp. Only one sample of chicken leg was contaminated with L.
Osaili et al. Besides the fact that only one sample was contaminated with L. The population of indicator microorganisms was higher in samples obtained on the surfaces of wet conveyor belts. At the same time, the populations of microorganisms on poultry meat transport on wet or dry conveyor belts did not differ, highlighting that the use of automatic cleaning system with water is not mandatory and its removal does not pose public health into risk and allow a reduction on the use of potable water in poultry slaughterhouses.
Ordinance No. Technical regulations of technology, hygiene and sanitary inspection of poultry meat. Presence of mesophilic, psychophilic and coliform microrganism in different samples of poultry products. Program of hygienic quality in poultry production. Poultry diseases. The effect of polyesterurethane belt surface roughness on biofilm formation and its cleaning efficiency.
Food Control. Listeria monocytogenes in poultry facilities: serologic and genetic markers to trace its dissemination. Listeria monocytogenes in two different poultry facilities: manual and automatic evisceration. Washington: APHA,
Matricaria chamomilla CH 12 is a phytotherapeutic or homeopathic product, which has been used to reduce stress. Here, we examined its effect on preventing handling stress in bovines. Sixty Nelore calves were randomly distributed into two equal groups. One group was administered Matricaria chamomilla CH 12 in diet and the other the 'control' was not. Animals in both groups were maintained unstressed for 30 days to adjust to the feeding system and pasture, and were then stressed by constraint on the 31th, 38th, 45th and 60th experimental days.
Scientific Research An Academic Publisher. Banzatto, D. ABSTRACT: Growing concern to increase life expectancy has promoted several studies in the field of nutrition, especially those on food and their effects on the human body. Assays have been performed to improve their nutritional quality. In fact, there is considerable interest in encouraging development of new ingredients, with the innovation in food products and the establishment of new market niches for these ingredients.