Natera Vanice, Isidoro William, Landgraf Mariza, Lacorte Gustavo Augusto, de Melo Franco Bernadette Dora Gombossy, Hoffmann Christian, Pinto Uelinton Manoel, Jurkiewicz Cynthia
Food Research Center, Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Food Research Center, Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, SP, Brazil; Instituto Federal de Minas Gerais - Campus Bambuí, Bambuí, MG, Brazil.
Food Res Int. 2025 Nov;219:116888. doi: 10.1016/j.foodres.2025.116888. Epub 2025 Jun 20.
Minas Gerais is known for producing raw milk artisanal cheeses, particularly Serra da Canastra. These cheeses are traditionally produced using a natural whey starter culture (NWS) known as pingo. The role of pingo in shaping cheese characteristics remains poorly understood. This research evaluated the microbiological and physicochemical effects of pingo on the artisanal cheese using a laboratory-scale model. Experimental cheeses were produced with pingo using two input frameworks: raw milk with high bacterial content and thermized milk with lower bacterial content. Control cheeses were made without pingo. Samples were analyzed during production and over 60 days of ripening for microbial counts (lactic acid bacteria (LAB), coliforms and Escherichia coli), pH, a, acidity and NaCl content. The microbial composition was determined by 16S rRNA sequencing. The logistic model was adjusted during 24 h of manufacture and the Weibull model was adjusted during ripening. Results indicated that during the production of the cheeses the maximum growth rate (μ) for E. coli was 25 % lower in cheeses produced with thermized milk and NWS compared to cheese without the addition of NWS. In raw milk cheeses, μ for E. coli was 2.3 to 3.0 times higher and no effect of NWS was observed, suggesting that NWS inhibits the growth of indicator microorganisms during cheese manufacturing only when the initial contaminant count is low. The time for the first decimal reduction (δ) of E. coli and coliforms during cheese ripening decreased by half with the addition of pingo, regardless of the type of milk used. The main genera identified in NWS was Streptococcus and a low relative abundance of Lactococcus. Cheeses produced with NWS presented a high prevalence of Streptococcus, followed by Lactococcus and Lactobacillus. In contrast, the cheese produced with raw milk and without NWS presented a high prevalence of Lactococcus. This study highlights the crucial role of pingo in reducing microbial loads and enhancing cheese safety, particularly when high- quality milk with low bacterial content is used, but its effectiveness is limited in poor-quality milk frameworks.
米纳斯吉拉斯州以生产手工生乳奶酪而闻名，尤其是卡纳斯塔山脉奶酪。这些奶酪传统上是使用一种名为“pingo”的天然乳清发酵剂制作而成。然而，pingo对奶酪特性形成的作用仍鲜为人知。本研究采用实验室规模模型评估了pingo对这种手工奶酪的微生物学和理化影响。使用pingo通过两种输入框架制作实验奶酪：细菌含量高的生乳和细菌含量低的热巴氏杀菌乳。对照奶酪不使用pingo制作。在生产过程以及长达60天的成熟过程中，对样品进行微生物计数（乳酸菌、大肠菌群和大肠杆菌）、pH值、a*值、酸度和氯化钠含量分析。通过16S rRNA测序确定微生物组成。在制作的24小时内拟合逻辑模型，在成熟期间拟合威布尔模型。结果表明，在奶酪生产过程中，与未添加NWS的奶酪相比，使用热巴氏杀菌乳和NWS制作的奶酪中大肠杆菌的最大生长速率（μ）低25%。在生乳奶酪中，大肠杆菌的μ值高2.3至3.0倍，且未观察到NWS的影响，这表明仅当初始污染物计数较低时，NWS才会在奶酪制作过程中抑制指示微生物的生长。无论使用何种类型的牛奶，在奶酪成熟过程中添加pingo后，大肠杆菌和大肠菌群首次减少一个对数级（δ）的时间缩短了一半。在NWS中鉴定出的主要属是链球菌属，乳酸球菌属的相对丰度较低。使用NWS制作的奶酪中链球菌的流行率很高，其次是乳酸球菌属和乳杆菌属。相比之下，用生乳且不使用NWS制作的奶酪中乳酸球菌属的流行率很高。本研究强调了pingo在降低微生物负荷和提高奶酪安全性方面的关键作用，特别是在使用细菌含量低的优质牛奶时，但在质量较差的牛奶体系中其效果有限。
