Pasquali Frédérique, Valero Antonio, Possas Arícia, Lucchi Alex, Crippa Cecilia, Gambi Lucia, Manfreda Gerardo, De Cesare Alessandra
Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, Bologna, Italy.
Department of Food Science and Technology, University of Córdoba, Agrifood Campus of International Excellence ceiA3, Córdoba, Spain.
Front Microbiol. 2022 Aug 25;13:959648. doi: 10.3389/fmicb.2022.959648. eCollection 2022.
Artisanal cheeses are produced in small-scale production plants, where the lack of full automation and control of environmental and processing parameters suggests a potential risk of microbial contamination. The aim of this study was to perform a longitudinal survey in an Italian artisanal factory producing a spreadable soft cheese with no rind to evaluate the inter- and intra-batch variability of physicochemical and microbial parameters on a total of 720 environmental and cheese samples. Specifically on cheese samples, the evaluation was additionally performed on physicochemical parameters. Cheese samples were additionally collected during 15 days of storage at constant temperatures of 2 and 8°C, as well as a dynamic profile of 2°C for 5 days and 8°C for 10 days. Furthermore, Enterobacteriaceae isolates were identified at species level to have a better knowledge of the environmental and cheese microbiota potentially harboring human pathogens. High inter-batch variability was observed for lactic acid bacteria (LAB) and total bacteria count (TBC) in cheese at the end of production but not for pH and water activity. A temperature of 8°C was associated with a significantly higher load of Enterobacteriaceae in cheeses belonging to batch 6 at the end of storage, and this temperature also corresponded with the highest increase in LAB and TBC loads over cheese shelf life. Results from generalized linear mixed models (GLMMs) indicated that drains in the warm room and the packaging area were associated with higher levels of TBC and Enterobacteriaceae in cheese. Regarding foodborne pathogens, no sample was positive for verotoxigenic (VTEC) or , whereas six and one pullorum isolates were collected in cheese samples during storage and processing, respectively. Regarding Enterobacteriaceae, 166 isolates were identified at species level from all batches, with most isolates belonging to and , , , and evidencing the need to focus on standardizing the microbial quality of cow milk and on hygienic procedures for cleaning and disinfection especially in warm and maturation rooms. Further studies should be performed to investigate the potential pathogenicity and antimicrobial resistance of the identified Enterobacteriaceae species in artisanal cheeses.
手工奶酪在小规模生产工厂中生产，这些工厂缺乏对环境和加工参数的完全自动化及控制，这表明存在微生物污染的潜在风险。本研究的目的是在一家意大利手工工厂进行纵向调查，该工厂生产一种无外皮的可涂抹软奶酪，以评估总共720个环境和奶酪样品的理化及微生物参数在批次间和批次内的变异性。具体针对奶酪样品，还对理化参数进行了评估。在2℃和8℃恒温下储存15天期间额外收集了奶酪样品，以及在2℃下储存5天和8℃下储存10天的动态情况。此外，对肠杆菌科分离株进行了种水平鉴定，以便更好地了解可能携带人类病原体的环境和奶酪微生物群。在生产结束时，奶酪中的乳酸菌（LAB）和总细菌数（TBC）存在较高的批次间变异性，但pH值和水分活度不存在批次间变异性。在储存结束时，8℃的温度与第6批奶酪中显著更高的肠杆菌科菌负荷相关，并且该温度也对应着奶酪保质期内LAB和TBC负荷的最高增加。广义线性混合模型（GLMMs）的结果表明，暖房和包装区域的排水与奶酪中较高水平的TBC和肠杆菌科菌有关。关于食源性病原体，没有样品对产志贺毒素大肠杆菌（VTEC）呈阳性，而在储存和加工期间，分别在奶酪样品中收集到6株鸡白痢沙门氏菌和1株鸡伤寒沙门氏菌分离株。关于肠杆菌科，从所有批次中在种水平鉴定出166株分离株，大多数分离株属于阴沟肠杆菌、产气肠杆菌、阪崎肠杆菌、聚团肠杆菌和弗氏柠檬酸杆菌，这表明需要专注于规范牛奶的微生物质量以及清洁和消毒的卫生程序，特别是在暖房和成熟室。应进行进一步研究，以调查手工奶酪中鉴定出的肠杆菌科菌种的潜在致病性和抗菌耐药性。
