Evaluation of minimum ripening time of artisanal mountain cheese from Santa Catarina prior to selling

Abstract

Artisanal mountain cheese (queijo artesanal serrano; AMS) is produced from raw milk, which makes it a suitable medium for the multiplication of pathogenic microorganisms. The ripening process involves physical, chemical and microbiological factors unfavorable to pathogen development. For this reason, the Brazilian legislation requires a minimum ripening time of 60 days. However, according to Normative Instruction (NI) no 30, of August 7, 2013, and Decree no. 9.013, of March 29, 2017, this time can be reduced provided that scientific studies show that there is no alteration in the safety of the product. This study aimed to evaluate the microbiological quality of AMS in 19 cheese factories in the Serra Catarinense region, at 14, 21, 28 and 35 days of ripening, and to determine which period would meet the microbiological limits. A total of 76 samples of AMS, 19 samples of water and 19 samples of raw milk were studied. The microorganisms were investigated following Ordinance no. 146, of March 7, 1996. The investigation and count of coliforms at 30 °C, E. coli and coagulase-positive Staphylococcus followed protocols by Silva et al. (2010), using Petrifilm™. The investigation of Salmonella spp. followed Silva et al. (2010), whereas the investigation of Listeria monocytogenese and count of mesophilic aerobes followed NI no. 30, of June 26, 2018. Water potability was evaluated by the Most Probable Number (MPN) technique, in accordance with NI no. 30/2018 and Consolidation Ordinance no. 5, of September 28, 2017. Results were tested by Analysis of Variance and Linear Regression using the SAS statistical package with significance determined at p < 0.05. No safe ripening period for sale could be determined. At 35 days of ripening, 14 farms still showed counts above the limit for the microorganisms described in the legislation. On one of the farms, the presence of L. monocytogenes was detected in the four evaluated periods, demonstrating that ripening was not efficient to eliminate the pathogen. The microbiological quality of the milk was not satisfactory, with 63.16% of the samples not conforming to the standards. As regards the potability of the water used in the cheese factories, 52.63% of the analyzed samples showed unsatisfactory results. The research revealed heterogeneity in the hygienic-sanitary standards adopted by the cheese factories, indicating that there is a need for training in Good Agricultural Practices and Good Manufacturing Practices, support from institutions, periodic inspection and commitment of producers to standardize the process.