Tratamentos de pré-resfriamento sobre a qualidade de carne de peito de frango, Bressan et al. -MATERIAIS E MÉTODOO presente experimento foi conduzido em frigorífi-co comercial no município de Jundiaí-SP, no período de março a julho de 1997, compreendendo estações do outono e inverno cujas temperaturas médias variam de 18 a 25 o C. TRATAMENTOS DE PRÉ-RESFRIAMENTO E RESFRIAMENTO SOBRE
Nas últimas décadas, tem-se observado um crescente interesse dos consumidores pelas questões relacionadas à segurança dos alimentos. Os governos têm sido pressionados a adotar medidas que assegurem a inocuidade dos alimentos e, consequentemente, legislações rigorosas quanto à contaminação dos alimentos por agentes físicos, químicos e microbiológicos estão sendo implantadas. Dentro desse panorama, conhecer a percepção do consumidor brasileiro sobre o tema é extremamente relevante. No presente estudo, avaliaram-se, em duas grandes cidades brasileiras (Campinas-SP e Rio de Janeiro-RJ), os critérios utilizados por consumidores para a compra de produtos alimentícios e suas visões sobre os riscos potenciais de contaminação dos alimentos. Avaliou-se também a percepção dos consumidores sobre a rastreabilidade e seu papel na melhoria da segurança dos alimentos, utilizando-se a metodologia focus group. Três sessões de discussão foram conduzidas (duas em Campinas e uma no Rio de Janeiro), tendo sido observadas diferenças entre os consumidores das distintas praças. Os consumidores de Campinas mostraram-se mais preocupados e interessados no assunto do que os do Rio de Janeiro, pois relataram buscar mais informações nos rótulos de alimentos. Menções relacionadas a riscos, como intoxicação alimentar, botulismo e agrotóxicos foram comuns para os entrevistados das duas cidades e, entre os principais produtos considerados com risco à saúde, ficaram as carnes e os frutos do mar, sendo estes últimos com maior ênfase no Rio de Janeiro. Dentre os produtos reconhecidos como seguros, destacaram-se as frutas (produzidas sem agrotóxicos), os legumes e os produtos secos/desidratados. Em todos os grupos, observou-se grande preocupação com a contaminação por agrotóxicos e metais pesados. Em termos microbiológicos, ambas as praças destacaram os riscos com bactérias, especialmente a Salmonella. O tema rastreabilidade se mostrou relevante nos três grupos, pois esta deve contribuir para o recolhimento mais eficiente de produtos, caso seja necessário. No entanto, sob a ótica do consumidor, a rastreabilidade leva ao aumento dos preços, embora aumente a confiança em relação à segurança dos alimentos. Muitas das preocupações dos consumidores refletem as informações publicadas em revistas e jornais, como o caso da crença de que hormônios são utilizados na cadeia da carne de frango. Indústria e varejistas devem incrementar a comunicação de informações científicas sobre a segurança dos alimentos, contribuindo, assim, na educação do consumidor.
The occurrence of Escherichia coli O157:H7 was evaluated in 886 samples of hamburgers produced by eight manufacturers in the south and southeast of Brazil from January to September of 1997. The pathogen was not detected in any of the samples analyzed, although 17 (1.9%) showed the presence of E. coli strains, which presented agglutination with O157 antiserum. These strains were not confirmed, since a subsequent identification indicated that they were fermentation positive for sorbitol, incapable of agglutination with the antisera of other commercial brands, and nonproducers of verocytotoxins. A high rate of false-presumptive-positive tests was observed with strains of enterobacteria when isolated by the culture method and when using a commercially purchased enzymatic immunoassay. This high rate of false presumptive positives was likely because the initial screening for sorbitol-negative strains was carried out using phenol red sorbitol 4-methylumbelliferyl-beta-D-glucuronide agar, which was shown to be inadequate for this purpose.
The first experiment was conducted to determine the effects of varying voltage, 20, 40, 80, and 100 V at 60 Hz, on stunning efficiency, blood loss, and carcass defects. In the second experiment, the same parameters were evaluated to determine the effects of varying frequency, 60, 200, 350, 500, and 1,000 Hz at 40 V. A control group for both experiments was not stunned. At 40V, 30 to 50 mA, 90% of the birds were unconscious, as shown by no response to comb piercing, and blood loss was maximized (55.3%). When varying the stunning frequency, maximum blood loss (73.1%), 90% of the birds were unconscious, and minimum carcass defects were observed at 1,000 Hz, 40 V. In the third experiment, birds were stunned at 40 V, 1,000 Hz and deboned immediately after defeathering (hot boning) and chilled or deboned after passing through all stages of a commercial abattoir operation (conventional boning). Control lots were unstunned and followed normal abattoir stages. Average shear value was significantly lower for stunned compared to unstunned birds (6.0 vs. 7.1 kg/g), although tenderness scores, as measured by a trained panel, were not significantly different (6.6 for stunned birds vs. 6.1 for unstunned). Scores for juiciness were also not significantly different (5.5 for stunned vs. 5.8 for unstunned). Average shear value was also significantly lower for conventionally boned birds (5.2 kg/g) than for hot boned birds (7.9 kg/g). Sensory analysis confirmed the shear value results. Conventionally boned breasts had an average tenderness score of 7.4 vs. an average of 5.3 for hot boned breast. No statistical differences were observed with respect to juiciness, although a score of 6.2 was observed for conventionally boned breast meat vs. a score of 5.1 for hot boned breast meat.
Ácidos or gânicos diluí dos f or am ut ilizados na sanit ização do tensor f asci ae l ateae bovino par a r eduzir sua micr obiot a super f icial e aument ar a vida-de-pr at eleir a da car ne r ef r iger ada. Após os t r at ament os e em int er valos de t r ês e cinco dias de est ocagem r ealizou-se análises micr obiológicas, det er minação de per da de peso, ver if icação do pH e análise sensor ial. O s t r at ament os r eduzir am signif icat ivament e a car ga micr obiana dos músculos e mant iver am est a r edução pelo per í odo de nove dias. Nos músculos submet idos aos t r at ament os obser vouse per das de peso super ior es ao gr upo cont r ole. Após t r ês dias de est ocagem, os escor es at r ibuí dos aos músculos t r at ados com a solução de ácidos or gânicos e ao cont r ole f or am est at ist icament e super ior es aos dos músculos t r at ados com a solução ácida, seguida de alginat o de cálcio e aos t r at ados com a solução ácida mais alginat o de cálcio. Ver if icou-se t ambém que os t r at ament os não modif icar am a apar ência dos músculos.
The purpose of this work was to evaluate the effects of different feed withdrawal (FW) periods (3, 6, 9, 12, 15, and 18 h) on live broiler weight loss, dressed and chilled carcass yields, and chilled breast meat quality attributes of chickens reared in an alternative system, without the use of any antibiotics, growth promoters, coccidiostats, or ingredients from animal sources. Live weight loss and dressed and chilled carcass yields after FW were determined, and also fillet color, waterholding capacity (WHC), pH, shear value, cooking loss, and proximate composition, and a sensory analysis was conducted. Longer FW periods resulted in significant (P ≤ 0.05) increases in live broiler weight losses, from 1.3 to 5.3% in the 18-h period. The drops in dressed and chilled carcass yields became statistically significant at 12 h of FW, with dressed carcass yields of 65.2% after 3 h of FW and 63.8% after 12 h. Chilled carcass yields dropped from 68.8% after 3 h of FW to 67.0% after 12 h. Fillet color, as indicated by the L* values, became darker with longer FW periods, as shown by regression analysis. No statistical differences were observed for the a* values, b* values, WHC, cooking losses, and proximate composition of the fillets for the different FW periods. The Pearson correlation values showed a significant but low negative correlation between fillet pH and shear force, which varied with FW period. The highest carcass yields were obtained for broilers submitted to FW periods of between 3 and 9 h.
To study the effects of chilling methods and hot-boning on quality parameters of M. longissimus lumborum (LL) of Nelore steers, sixteen left-carcass sides were electrically stimulated and the LL muscles were hot-boned and chilled at -20°C (HBVFC) or 0°C (HBO). Eight control left-carcass sides were cold-boned (AT). All muscles were vacuum-packaged and aged at 0°C for 14 d. Shear force and tenderness of the AT-treated muscles were not different from HBO-treated muscles. The shear force values of the HBVFC muscles were higher after 7 and 14 d post-mortem (pm) compared to those of the AT muscles, but there was no difference from the HBO muscles. Aging did not reduce the shear force values of the HBVFC muscles. The purge losses of the HBVFC muscles were higher than those of the HBO and AT muscles. The HBVFC muscles were less tender than the HBO and AT muscles at 14 d pm.
Ciênc. Tecnol. Aliment., Campinas, 21(2): 223-227, maio-ago. 2001 223 RESUMOFoi verificada a ocorrência de Escherichia coli O157:H7 em 340 amostras de produtos cárneos e ambiente industrial, provenientes de frigoríficos do Sul e Sudeste do Brasil, no período de abril/98 a abril/99. A presença de E.coli O157:H7 não foi detectada em nenhuma das amostras analisadas e os resultados da avaliação da sensibilidade dos métodos de detecção evidenciaram que tanto o método cultural quanto o imunoensaio da Neogem foram capazes de detectar a presença de E.coli O157:H7 em cultura pura em concentrações iniciais de menos de 0,5Log UFC/mL do caldo de enriquecimento.
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