Effect of pingo on the characteristics of artisanal cheese during ripening: Lactic acid bacteria (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry), microbiological, and physicochemical

Abstract

Raw milk artisanal cheeses hold significant social and economic value by preserving cultural traditions, supporting small-scale rural livelihoods, and strengthening local economies through traditional, value-added dairy production. These cheeses are made using pingo, a natural starter unique to each region. Despite its central role in cheesemaking, there is limited research on the importance of pingo in ensuring the safety of these traditional cheeses. This study aimed to investigate the effect of the addition of pingo on the physicochemical and microbiological properties and lactic acid bacteria (LAB) profile in artisanal cheeses during ripening. A cheesemaking facility in Serra Geral, Minas Gerais, Brazil, was selected for cheese production and ripening. A batch of milk was used to make the cheeses with and without pingo, which were then ripened for 28 d. Samples of fresh raw milk, pingo, and cheese (at 1, 7, 14, 21, and 28 ripening days) were collected for physicochemical and microbiological analysis. Lactic acid bacteria were identified by MALDI-TOF MS. The physicochemical characteristics of milk complied with legislation, and pingo was considered an acidic and salty ingredient. The microbial characteristics of the raw milk and pingo were not satisfactory, mainly for total coliforms and Staphylococcus spp., indicating the need to adopt good cheese production practices to meet One Health principles. During the 28-d ripening, the cheese became more acidic with lower moisture content. There was also a decrease in the microbial count (Escherichia coli, coagulase-positive staphylococci, and LAB). The use of pingo did not affect the cheeses' water activity, pH, acidity, and moisture content. However, it reduced the counts of total coliforms, E. coli, Staphylococcus spp., coagulase-positive staphylococci, and molds and yeasts. Lactobacillus plantarum was predominant, followed by Enterococcus faecalis. Pingo use improved the microbiological quality of the artisanal cheese throughout the 28-d ripening, and it was an important source of LAB. However, the 28-d ripening time was insufficient to reduce potentially pathogenic or spoilage bacterial counts.