Bacteriological Quality of Raw Milk Used for Production of a Brazilian Farmstead Raw Milk Cheese

Abstract

The objective of this study was to evaluate the bacteriological quality of raw cow's milk utilized for the production of Traditional Minas Serro cheese, a Brazilian farmstead raw milk cheese. Raw milk samples were collected from six farmstead cheese operations manufacturing raw milk cheese from cow's milk. Coliform count (CC) and Escherichia coli counts were determined using Petrifilm™ EC plates, and Staphylococcus aureus counts were determined using Petrifilm™ Staph Express count plates. The standard plate count (SPC) was determined using plate count agar. The somatic cell count (SCC) was determined with a DeLaval cell counter. The detection of Listeria monocytogenes was based in the ISO 11290-1 protocol. A total of 165 samples were analyzed, and the SPC was 1.85-7.88 log CFU/mL. Coliform were detected in 140 (84.8%) of the 165 samples, with counts of 1-6.39 log CFU/mL. E. coli was detected in 17 (10.3%) samples, with counts of 1-2.18 log CFU/mL. The SCC in raw milk was 10,000-1,390,000 cells per mL, with mean and geometric mean values of 247,000 and 162,181, respectively. The SCC did not differ significantly between the seasons (p>0.05), but differed between different farms (p<0.05). None of the 155 samples were positive for the presence of Listeria monocytogenes. S. aureus was isolated in 145 (94.1%) of the 154 samples, and the count was 1.47-5.03 log CFU/mL. The median of SPC, CC, and S. aureus counts differed significantly between seasons and between farms (p<0.05). Our results indicate that raw milk for production of farmstead raw milk cheese has a low incidence of L. monocytogenes and a high incidence of S. aureus, and suggest that measurements (such as SCC or SPC) may not serve as a predictor of other bacterial (including pathogenic) presence.

Genetic relationship between Escherichia coli strains isolated from dairy mastitis and from the stable fly Stomoxys calcitrans

“…These results thus reinforce the reported by Costa Sobrinho et al (2012) that the poor hygiene promotes the establishment and the circulation of microorganisms between animals of the herd, especially when good management practices are not commonly used.…”

“…This diversity was expected, since when dispersed in the environment, the occurrence of genetic exchange between different bacteria population can be enhanced. These microorganisms are subjected to adverse conditions (Costa Sobrinho et al 2012, Lopes et al 2012) instead of particular epidemiological situations, as shown by the fact there were no shared profiles between farms or the municipalities visited. This is the first study evaluating the genetic relationship of E. coli sub-populations isolated from mastitic milk and from flies.…”

Microbiological quality and safety assessment in the production of moderate and high humidity cheeses

“…However, there was no detection of this group of microorganisms in pasteurized milk samples (<0.3MPN mL -1 ), showing the pasteurization effectiveness process used by the dairies evaluated, which was confirmed by results of phosphatase (negative) and peroxidase (positive) tests. High levels of thermotolerant coliforms reported in raw milk samples analyzed can be related to deficient sanitary conditions of dairy farms or to hygienicsanitary problems in the milking process (MORAES et al, 2009;SOBRINHO et al, 2012;GALINARI et al, 2014;PIERI et al, 2014). Bacteria belonging to group of thermotolerant coliforms colonize mammals' intestine and their detection can indicate the presence of other pathogenic microorganisms of enteric origin.…”

“…Coagulasepositive Staphylococcus aureus is one of the most common pathogens infecting dairy cows and a major causative agent of mastitis. This microorganism is commonly isolated from raw milk and represents a potential risk for public health due to the possibility of staphylococcal toxin production (SOBRINHO et al, 2012). S. aureus, the main species of the CPS group, can produce toxin when it reaches 10 5 to 10 6 CFU per gram of food.…”

“…The presence of pathogens in milk products are a major concern in public health (SOBRINHO et al, 2012) and cheese consumption has been associated with foodborne disease outbreaks (FBDOs) in different parts of the world, since natural cheeses can support the growth of microorganisms including foodborne pathogens (CHOI et al, 2016). According to Brazilian regulatory standards, use of raw milk in ripened cheese production for a period less than 60 days is only allowed when technical and scientific studies attested that reducing the period will not compromise the product quality and safety (BRAZIL, …”