This research aimed to evaluate the occurrence of Staphylococcus aureus isolates in milk and in the milking environment of 10 small-scale farms (<400 L/d) located in the regions of Franca and Ribeirão Preto, state of São Paulo, Brazil. Two-hundred twenty samples of milk were collected from individual cows, along with 120 samples from bulk tank milk, 389 samples from milking equipment and utensils (teat cups, buckets, and sieves), and 120 samples from milkers' hands. Fifty-six Staph. aureus strains were isolated from 849 analyzed samples (6.6%): 12 (5.5%) from milk samples of individual cows, 26 (21.7%) from samples of bulk tank milk, 14 (3.6%) from samples collected from equipment and utensils, and 4 (3.3%) from samples from milkers' hands. Pulsed-field gel electrophoresis typing of the 56 Staph. aureus isolates by SmaI restriction enzyme resulted in 31 profiles (pulsotypes) arranged in 12 major clusters. Results of this study indicate a low incidence, but wide distribution of Staph. aureus strains isolated from raw milk collected from individual cows and surfaces of milkers' hands and milking equipment in the small-scale dairy farms evaluated. However, the high percentage of bulk milk samples found with Staph. aureus is of public health concern because raw, unprocessed milk is regularly consumed by the Brazilian population.
The aim of this study was to evaluate the application of the methodology of Fourier Transform Infrared spectroscopy (FT‐IR) to the identification of adulterated raw milk. A reference spectrum with 800 representative samples of the study area was built. Through the analysis of principal components, equations with a distinct number of factors were developed. For the validation test, 100 adulterated samples were used at three different concentrations of sodium bicarbonate, sodium citrate and non‐acid cheese whey. Results indicate that the FT‐IR can be used for the identification of adulterated milk with 0,05% and 0,075% of sodium bicarbonate and citrated respectively.
-The objective of this study was to develop calibrations to determine the concentration of some milk adulterants by using the automated methodology of Fourier Transform Infrared (FTIR). For construction of calibrations, samples were collected from 100 farms in the states of São Paulo and Minas Gerais. Samples were tainted with three different adulterants commonly used in the adulteration of raw milk: sodium bicarbonate (SB), sodium citrate (SC) and cheese whey (W).Each adulterant was used at three different concentrations (SB: 0.05, 0.10 and 0.25%; SC: 0.025, 0.050 and 0.075% and W: 5, 10 and 20%). For validation, 60 samples were collected in other farms, which were not considered at the development stage of calibration. Adulterants were added at the following concentrations: 0.03, 0.06, 0.10 and 0.12% for SB; 0.02, 0.04, 0.06 and 0.08% for SC and 5, 10 and 20% for W. Performance of each calibration was evaluated in terms of accuracy (Se), detection limit (DL) and determination coefficient (R 2 ). All calibrations presented R 2 higher than 0.91 with DL of 0.015%; 0.017% and 3.9% for SB, SC and W, respectively. Accuracy was 0.005%, 0.009% and 2.26% for SB, SC and W, respectively.Results show that the FTIR methodology can be used for determining the concentration of sodium bicarbonate, sodium citrate and whey in raw milk. Associated with automated equipment, it is a viable option for monitoring these adulterants, having low operational costs and high analytical performance as additional features.
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