Seasonality and collection routes influence the occurrence of non-acid unstable milk, the density and cryoscopy of milk supplied to a dairy industry in northern Minas Gerais

Abstract

The purpose of this study was to evaluate in the months, seasons and collection routes, the occurrence of non-acidic unstable milk (UNAM) and other milk categories, titratable acidity, density and cryoscopy in 10,654 samples from a dairy industry located in Montes Claros, MG, Brazil. Municipalities were grouped in collection routes: a) Bocaiuva; Brasilia de Minas, Coracao de Jesus and Sao Joao da Lagoa; b) Capitao Eneas and Janauba; c) Francisco Sa; Icarai de Minas and Sao Francisco; d) Juramento and Glaucilandia; e) Montes Claros; f) Pedras de Maria da Cruz, Japonvar, Lontra and Sao Joao da Ponte and g) Ubai. The milk category frequencies and alcohol test, titratable acidity, density and cryoscopy of milk by months, season and routes were evaluated. Chi-square tests and variance analysis showed the influence of month, season and route on titratable acidity, density and cryoscopy. Multiple correspondence analyzes described the association of milk and month or routes and alcohol test categories, titratable acidity, density and cryoscopy in relation to the seasons. The probability of occurrence of LINA by month and route groups was calculated by logistic regression. There were a higher percentage of samples within the normal range. Normal, UNAM, alkaline and acid milk results were respectively 79.46, 12.93, 4.14 and 3.48% of 10,271 results. Alcohol test positivity (n=10,561) was more frequent in late winter. UNAM was associated with the transition from drought to rainy season, most likely to occur in September and January. The Brasilia de Minas, Icarai de Minas and Ubai routes presented higher nonconformities and probabilities for UNAM occurrence.