Antônio Nonato de Oliveira

Contagem celular somática: relação com a composição centesimal do leite e período do ano no Estado de Goiás

Milk quality is a crescent concern in Brazil and the Goias State does not have any current studies on this subject, although it is among the major producers in the country. The aim of this survey was to verify the relationship between somatic cell count (SCC) and milk composition (fat, protein, lactose and total solids content) and the influence of year period in SCC in Goias State, Brazil. Data were obtained from October 2002, to September 2003 in the Laboratory of Milk Quality of the Center of Food Research in the Veterinary School of the Federal University of Goias. SCC was analyzed through flow citometry and milk composition by infrared differential absorption. The year period was divided in two seasons: a rainy season, from November to April, and a dry season, from May to October. Protein, lactose and total solids content decreased as SCC elevated. Environmental temperature showed positive and significant correlation to score of somatic cells, and the highest averages of SCC occurred in the dry season.

Microbiological quality and other characteristics of refrigerated chicken meat in contact with cellulose acetate-based film incorporated with rosemary essential oil

Antimicrobial active packaging delays or inhibits microorganism growth in packed products, and it can be used in a variety of food systems. The objective of the present research was to develop packaging incorporated with natural antimicrobial agents (active film). The effects of the active film on the spoilage, pathogenic microorganism counts, pH and color of the refrigerated chicken breast cuts were analyzed. Cellulose acetate-based active films incorporating two concentrations (20% and 50%, v/w) of rosemary (Rosmarinus officinalis L.) essential oil were manufactured and placed in contact with the chicken breast cuts for six days. An analysis of variance and mean comparison tests (Tukeys test, p<0.05) were performed on the results. The films that contained 20% essential oil and were intercalated with chicken breast samples did not demonstrate significant effects on the control of psychrotrophic or total coliform microorganisms during the storage period; however, the films incorporated with 50% essential oil demonstrated efficacy toward the control of coliforms during the storage of the samples (6 days, 2 ± 2oC). The pH was related to the psychrotrophic microorganism count and was not influenced by the treatment. The color was not influenced by the time of storage or the treatment. The results demonstrate that active films incorporating 50% rosemary essential oil are effective at controlling certain microorganisms in chicken breast cuts.

PCR and ELISA (VIDAS ECO O157(®)) Escherichia coli O157:H7 identification in Minas Frescal cheese commercialized in Goiânia, GO.

Escherichia coli O157:H7 has been incriminated in food poisoning outbreaks and sporadic cases of hemorrhagic colitis and hemolytic uremic syndrome in many countries. Considering the high susceptibility of Minas Frescal cheese to contamination by E. coli O157:H7, the aim of this study was to determine the occurrence of this pathogen through PCR (Polymerase Chain Reaction) and ELISA (VIDAS ECO O157®, bioMérieux, Lyon, France) test. Thirty cheese samples manufactured by artisan farmhouse producers were collected from open-air markets in Goiânia and thirty from industries under Federal Inspection located in Goiás State which trade their products in supermarkets in Goiânia. E. coli O157:H7 was detected in 6.67% samples collected in open air markets using ELISA, and 23,33% with PCR. The pathogen was not detected in samples from industries under Federal Inspection.

Spatial locality in pocket switched networks

The current Internet design falls short in scenarios characterized by intermittent connectivity and absence of supporting infrastructure. Pocket switched networking allows communication between portable handheld user devices in such environments through the store-carry-forward paradigm. This involves storing data in device memory, exploiting user movement to physically transport the data, and forwarding through available short-range wireless interfaces. In this regard, user devices can be leveraged as data mules for point-to-point communication in two main scenarios: (i) conveying data between major infrastructures in urban areas (e.g., transporting sensor data to gateways in smart cities); and (ii) extending wireless coverage to provide connectivity in developing regions (e.g., bridging user devices and remote Internet access points). User movement in such scenarios exhibit spatial locality, which is the preference to a geographical location than others. This feature influences the data transfer opportunities that exist between different sets of users. This paper investigates the impact of locality on routing in pocket switched networks by: (i) evaluating the performance of existing routing strategies for point-to-point communication over different degrees of locality; and (ii) providing insights towards enhancing routing performance for realizing the aforementioned application scenarios through locality awareness.

Collecting Sensed Data with Opportunistic Networks: The Case of Contact Information Overhead

The rising human population in urban environments drives the mission towards smart cities, which envisions a wide deployment of sensors in order to improve the quality of living. In this regard, opportunistic networks (OppNets) present an economical means of collecting delay tolerant data from sensors to their respective gateways for providing various Smart City services. Due to the distributed nature of the network, encounter-based routing protocols achieve acceptable throughput by requiring nodes to exchange and update contact information on an encounter basis. Unfortunately, sufficient insight into the associated overhead is lacking in the literature. Hence, we contribute by modelling contact information overhead and investigating its impact on OppNet routing, particularly in terms of data exchange success and energy consumption on portable handheld devices. Our findings reveal that the expected contact information overhead in Smart City scenarios significantly reduces data exchange success and increases energy consumption on portable handheld devices, thereby threatening the feasibility of the technology. We address this issue by proposing an algorithm that can be incorporated into encounter-based routing protocols to reduce contact information overhead without compromising throughput. Simulation results show that our proposed algorithm reduces the average contact information overhead, increases throughput and reduces average energy consumption.

Níveis de células somáticas sobre a proteólise do queijo Mussarela

The aim of this trial was to evaluate the effect of somatic cells count on the microbiota and proteolysis of Mozzarella cheese during the storage period. Cows presenting different levels of SCC were selected: 200,000 cells/mL; >200,000 to 400,000 cells/mL; >400,000 cells/mL to 750,000 cells/mL and >750,000 cells/mL, which were not treated with antimicrobial prior or on the milk sampling day. The cheeses produced were evaluated after 1, 15 and 30 days of storage for coliforms count at 35oC, coliforms count at 45oC, psychrotrophic and lactic acid bacteria. Meanwhile, extent and depth of proteolysis indexes were determined. The complete trial was repeated four times and experimental design used was randomized blocks. ANOVA was used for repeated measurements and the p-value was adjusted for multiple comparisons by Tukeys test. High somatic cell count milk showed lower concentration of protein and higher of non-protein nitrogen. There was a decrease of lactic acid bacteria in cheese made from milk containing high somatic cells count (>750,000cells/mL). Nevertheless, during the storage period, a significant increase in the extent and depth of proteolysis occurred in cheeses produced from milk with SCC higher than 400,000 cells/mL. Therefore, in order to produce a high quality Mozzarella cheese, it is necessary to control the raw material, so that SCC should be lower than 400,000 cells/mL.

Efeito da temperatura e do tempo de armazenamento de amostras de leite cru nos resultados das análises eletrônicas

The aim of this study was to evaluate the effects of temperature and storage time of cooled samples of raw milk on the results of milk quality electronic analysis. Refrigerated raw milk samples were collected from expansion tanks for individual use of farms located in the middle region of the state of Goias, and stored at four different temperatures (3°C, 11°C, 17°C, and 25°C) for 16 days. Total bacterial count (TBC), somatic cell count (SCC), and chemical composition were performed daily. The results were submitted to analysis of variance in split plot design in randomized blocks, and the means were compared by Duncan test. We concluded that, when azidiol is added as preservative to samples for TBC, they can be analyzed up to 16 days after collection when stored at temperatures of 3°C and 11°C, and up to 10 days when stored at 17°C. Moreover, when bronopol is added as preservative, samples for SCC and chemical composition analysis can be stored for up to 16 days after collection when stored at temperatures of 3°C and 11°C, and for up to seven days when stored at 17°C.

QUALIDADE DO LEITE CRU REFRIGERADO OBTIDO ATRAVÉS DE ORDENHA MANUAL E MECÂNICA Quality of refrigerated raw milk obtained by milking machine and manual

The objective of this paper to evaluate the centesimal composition, SCC and TBC, of the cooled raw milk obtained from milking manual and mechanic in Sudoeste Goiano. Samples were collected from cooled raw milk at 87 dairy farms that performed manual milking and 55 properties with mechanic milking in the period December 2010 to February 2011. Electronics Analysis were performed at the Laboratorio de Qualidade do Leite do Centro de Pesquisa em Alimentos da Escola de Veterinaria e Zootecnia da Universidade Federal de Goias. The experimental design was completely randomized with two treatments: one treatment of milk obtained by manual milking and the two treatment of milk obtained by mechanic milking. Statistical analysis was performed using the software SISVAR-UFLA, was used to test FISCHER 5% significance for the analysis of averages. In physico-chemical composition, lactose was the only component that varied according to the type of milking, and in the milk obtained by manual milking its concentration was higher than that obtained by milking machine. High TBC cooled raw milk showed poor preservation of milk production at source. The SCC of milk milked manually if framed within the ceiling set by the legislation, however mechanically milked in milk SCC was highest. These results indicate the need for care hygienical-sanitary more effective, in order to prevent the incidence of mastitis in dairy herds in the region.