Abstract
Milk heat stability, evaluated through alcohol or alizarol test, is affected by several factors, the main one is milk acidificat ion. However, enzymatic hydrolysis, high somatic cells counts (SCC), excess of calcium ions and ethanol addit ion also af fect its stability to alcohol , reducing its correl ation with heat stability. The objective of this work was to determine the occurrence of instable non acid milk (LINA) in Sapopema-PR, evaluate heat stability of LINA and its relation with SCC and total bacteria count (TBC) and also evaluate the interference of alcohol concentration, used to perform alcohol test, on milk stability. A total of 85 samples were submit to alcohol test at 68, 72, 75 e 78%, determination of Dornic acidity, boiling test , SCC and TBC. High occurrence of LINA was observed. The highest frequency of LINA 65,88% occurred at alcohol concentration of 78% v/v and the lowest 15,29% at 68% v/v. With one exception, LINA samples were stable to boiling test, showing that its rejection by industry that produces pasteurized milk and dairy products would be unnecessary. The means obtained to SCC and TBC were elevated in both LINA samples and instable samples with acquired acidity.
Highlights
The highest frequency of LINA 65,88% occurred at alcohol concentration of 78% v/v and the lowest 15,29% at 68% v/v
LINA samples were stable to boiling test, showing that its rejection by industry that produces pasteurized milk and dairy products would be unnecessary
The means obtained to somatic cells counts (SCC) and total bacteria count (TBC) were elevated in both LINA samples and instable samples with acquired acidity
Summary
Esse trabalho faz parte do Projeto “Leite do Paraná” do programa Universidade Sem Fronteiras, da Secretaria de Estado da Ciência, Tecnologia e Ensino Superior do Paraná. Entre os meses de junho e julho de 2009, 85 amostras de leite cru de propriedades leiteiras do município de Sapopema, na região do Norte Pioneiro do Paraná. As amostras foram colhidas em bags estéreis e mantidas em caixas isotérmicas com gelo reciclável até a chegada no Laboratório de Inspeção de Produtos de Origem Animal da Universidade Estadual de Londrina. Todas as amostras foram analisadas no momento da sua chegada no laboratório. Foram realizadas as provas de acidez Dornic e prova da fervura, de acordo com a Instrução Normativa 68 (BRASIL, 2006). A contagem bacteriana total (CBT) e a contagem de células somáticas (CCS) foram realizadas por citometria de fluxo pela Associação Paranaense de Criadores de Bovinos da Raça Holandesa (APCBRH), laboratório de referência do Paraná. Os resultados das análises de amostras consideradas instáveis ao alizarol sem acidez adquirida (LINA) foram então comparados com os resultados das amostras estáveis ao alizarol
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