A microbiological and physical-chemical based evaluation of artisanal Minas cheese production in Rio Paranaíba city, Minas Gerais, Brazil

Abstract

The aim of this study was to evaluate the microbiological and physical-chemical features of the water and milk used in the preparation of artisanal cheese produced in seven dairies, located in Rio Paranaíba, Minas Gerais, Brazil, in order to ascertain the conformity of these parameters with the current legislation. Physical-chemical analyzes of water (alkalinity, acidity, residual chlorine, chlorine and pH), milk (fat, protein, total solids, nonfat dry extract, acidity, cryoscopy and density) and cheese (moisture content, presence of starch and alkaline phosphatase) were performed. Also, it was determined the most probable number of coliform at 30 °C, at 45 °C and mesophilic count in the samples of water, milk and cheese. Cheese weight, diameter and height were also determined to verify the patterning of the physical format of cheeses. The water used by dairies showed satisfactory microbiological characteristics. However, the water in properties 2 and 7 showed mean values of alkalinity approximately 2 times higher and lower than the recommended range (10 to 50 mg CaCO3.L-1), respectively. Considering the confidence intervals, no water sample showed satisfactory results for alkalinity and residual chlorine determinations. With regards to raw milk samples, three samples showed mesophilic bacteria count greater than 1 x 105 CFU/mL (property 1, 5 and 7), whereas four and two samples showed number of coliforms at 30 °C and at 45 °C higher than 1100 NMP/mL, respectively. The milk produced in the property 2 showed confidence interval values for density (1.033 to 1.035), above the recommended limit. In addition, the confidence interval for the freezing point of milk in all properties were out of recommended values (-0.550 to -0.530 °H). Seventy-five percent of the cheeses had coliform counts at 30 °C greater than 1 x 103 MPN/g and 100% of the samples had humidity valueabove 45.9% (maximum allowed after maturation). The weight of cheeses from the properties 2, 4, 5, 6 and 7 also exceeded the recommended limit (1-1.2 kg). The artisanal cheese-making process requires some adjustments to meet the standards of current legislation, aiming to bring added value and greater product safety.