Avaliação do uso de ozônio em temperaturas de leite cru refrigerado na contagem de psicrotróficos

A qualidade do leite cru está associada às boas práticas de ordenha proveniente de rebanhos sadios e com refrigeração obrigatória do leite cru na granja leiteira entre 4 e 7° C, podendo chegar até, no máximo, 9° C durante a coleta final (BRASIL 2018). Embora a refrigeração seja eficaz para aumentar a vida útil do leite cru, a manutenção das baixas temperaturas favorece a multiplicação de bactérias psicrotróficas, que produzem proteases e lipases termorresistentes, que permanecendo ativas mesmo após a pasteurização, podem afetar negativamente, tanto o próprio leite, quanto seus derivados (RIBEIRO et al., 2018). Visando reduzir a contagem de microrganismos psicrotróficos no leite cru, o presente trabalho avaliou a eficácia da aplicação de ozônio, considerado um bactericida verde por não ser poluente e não deixar resíduos no alimento, diretamente no tanque de resfriamento. As amostras de leite cru foram obtidas de um rebanho saudável e recolhidas diretamente do tanque de resfriamento da propriedade e armazenadas em frascos estéreis com volume de 6 litros sob refrigeração (4 e 9° C). A aplicação do ozônio seguiu delineamento fatorial com variáveis independentes sendo as temperaturas do leite (4 e 9° C) e os tempos de exposição ao ozônio (5 e 15 minutos) utilizando Gerador de Ozônio N202F Bivolt 500mg/h O³ Disinfector - Diluka Power. Foram retiradas amostras antes e após a ozonização. As amostras foram então armazenadas por 48 horas sob refrigeração (4° C) para permitir a proliferação da flora psicrotrófica. O teor de psicrotróficos e a contagem bacteriana total das amostras e do grupo controle foram avaliados em meio ágar bacteriológico PCA por 10 dias a 7° C e a 36° C por 24 horas, respectivamente. A aplicação de ozônio foi eficaz em reduzir a contagem de microrganismos psicrotróficos no tempo de 5 minutos a 4° C, esse resultado é extremamente satisfatório, visto que, a temperatura de aplicação é a mesma aplicada aos tanques de refrigeração nas propriedades, o que permitiria, facilmente, a aplicação nas próprias fazendas. Agradecimentos Agradecemos à equipe do Serviço de Orientação à Alimentação Pública da FMVZ-Unesp e ao proprietário da fazenda por disponilibizar o material utilizado na pesquisa. Referências BRASIL. Ministério da Agricultura, Pecuária e Abastecimento. Instrução normativa nº 76, de 26 de novembro de 2018. Regulamentos Técnicos que fixam a identidade e as características de qualidade que devem apresentar o leite cru refrigerado, o leite pasteurizado e o leite pasteurizado tipo A. Diário Oficial da União, Brasília, 2018. RIBEIRO JÚNIOR, J. C.et al. The main spoilage1 related psychrotrophic bacteria in refrigerated raw milk. Journal of dairy science, v. 101, n. 1, p. 75-83, 2018. PALAVRAS-CHAVE: Microbiologia dos alimentos, Qualidade do leite, Tecnologia verde

Effect of Integrated Nutrient Management on Growth, Yield Attributes and Economics of Spiny Brinjal (Solanum melongina L.) Var VRM (Br)-1

Background: An experiment on “Effect of Integrated Nutrient Management on Growth, Yield Attributes and Economics of Spiny Brinjal (Solanum melongina L.) var. VRM (Br)-1” were conducted at Adhiparasakthi Agricultural College farm, Vellore District, Tamil Nadu. Methods: Eleven treatments of integrated nutrient management viz., T1-RDF of N:P:K (100:50:30 kg/ha.), T2– FYM (25 t/ ha.), T3- Humic acid (20 kg/ha.), T4- RDF of N:P:K (100:50:30 kg/ha.) +FYM @25 t/ ha, T5- Humic acid (20 kg/ha.) + RDF of N:P:K (100:50:30 kg/ha.), T6- Azospirillum (2 kg/ha.), T7- Phosphobacteria (2 kg/ha.), T8- Azospirillum (2 kg/ha.) + Phosphobacteria (2 kg/ha.), T9 – 75% RDF of N (75 kg/ha.) + 100% RDF of P&K (50:30 kg/ha.) + Azospirillum (2 kg/ha.), T10 - 75% RDF of P (37.5 kg/ha.) + 100% RDF of N&K (100:30 kg/ha.) + Phosphobacteria (2 kg/ha.) and T11 - 75% RDF of N & P (75:37.5 kg/ha.) + 100% RDF of K (30 kg/ha.) + Azospirillum (2 kg/ha.) + Phosphobacteria (kg/ha.) replicated thrice in Randomised block design. Results: The various treatments of integrated nutrient managementin spiny brinjalclearly showed that growth and yield attributes were high in T11.The economic assessment of different treatments revealed that maximum net profit Rs.2,16,570/ha.with benefit cost ratio (2.60) was also recorded in treatment T11 75% RDF of N & P (75:37.5 kg/ha.) + 100% RDF of K (30 kg/ha.) + Azospirillum(2 kg/ha.) + Phosphobacteria (kg/ha.).

Evaluating the Inclusion of Cold-Pressed Rapeseed Cake in the Concentrate for Dairy Cows upon Ruminal Biohydrogenation Process, Ruminal Microbial Community and Milk Production and Acceptability

The aim of this trial was to assess the effect of feeding a concentrate including cold-pressed rapeseed cake (CPRC) on productive performance, milk quality and its sensory properties, ruminal biohydrogenation, and bacterial communities. Eighteen cows were paired, and two experimental diets (control vs. CPRC) were distributed within the pair. Concentrates were iso-energetic and iso-proteic and contained similar amounts of fat. The average days in milk, milk yield, and body weight of the animals were (mean ± SD) 172 ± 112 d, 585 ± 26 kg, and 25.4 ± 6.2 kg/d, respectively. The experiment lasted for 10 wk. Feeding CPRC resulted in lower ruminal saturated (p < 0.001) and higher monounsaturated (p = 0.002) fatty acids. Feeding CPRC increased Ruminococcus, Prevotella, and Entodinium but decreased Blautia; p-75-a5; undefined genera within orders Clostridiaceae and RF39 and within families Christensenellaceae, Lachnospiracease, and Ruminococcaceae; and fungi from the phylum neocallimastigomycota. The milk fatty acid profile was characterized by a lower n6:n3 ratio (p = 0.028). Feeding CPRC did not affect the milk yield, milk quality, or fat corrected milk (p > 0.05). Feeding CPRC improved the overall milk acceptability (p = 0.047). In conclusion, CPRC affected some microbial taxa, modified the biohydrogenation process, and improved the milk fatty acid profile and consumer acceptance without detrimental effects on milk production and composition.

Kinetics And Monte Carlo Simulation of UV Disinfection B. Subtilis Spores And SARS-CoV-2 In Dried Saliva Droplets

Surfaces can be contaminated by droplets produced coughing or sneezing. In this short, exploratory work, UV disinfection data from B. subtilis spores in dried saliva droplets were fitted to a first-order model. The model has a disinfection rate constant for single organisms, and a smaller one for aggregates (R2 ≥ 0.97). Changes in the fraction of organisms in aggregates (β) alone could account for the effects of different sized droplets in the experimental work. Since a wide spectrum of droplet sizes can be produced and some of the rate constants were uncertain, Monte Carlo simulation was used estimate the UV inactivation performance in dried saliva droplets in a range of conditions. Using conservative lognormal distribution for β, the model was applied to the UV disinfection of SARS-CoV-2 in dried droplets. It was shown that one-log reduction of SARS-CoV-2 was very likely (p>99.9%) and two-log reduction was probable (p=75%) at a dose of 60 mJ/cm2. Aggregates tend to be variable and limit the log reductions that can be achieved at high UV doses.