# Quantitative Microbiological Analysis of Artisanal Stretched Cheese Manufacture
## 1 Introduction  
The pasta filata cheeses share a unique processing step, when the curd is immersed in hot water or salt brine and mechanically stretched to a plastic consistency which can be formed or molded into a variety of shapes [1]. Some of this type of cheese are soft or semi-soft and usually consumed fresh or after a brief period of ageing (e.g., fresh Mozzarella, low-moisture Mozzarella, and Scamorza). Others, e.g., Caccioxallo, Kashkaval, Provolone, and Ragusano, are hard or semi-hard ripened cheeses with a considerable ageing period before consumption [2]. The history of some Slovakian artisanal types of steamed and stretched (pasta filata) cheeses can be observed in the Protections of Geographical Indications (PGI) of the following original agriculture products: Slovensky ostiepok, Slovenska parenica, Oravsky korbacik, Zazrivsky korbacik, and Zazrivke vojky. The records submitted to the PGI designations showed cooking, molding, or stretching processes as an integral part of traditional artisanal cheese manufacture have been used probably since the 17 th to mid-18 th centuries in the area of present Slovakia [3; 4; 5; 6; 7].  
Industrial pasta filata cheese production uses acid-coagulated or fermented rennet curd from cow, sheep, goat, or buffalo pasteurized milk. The process technology includes two essential steps: cooking and stretching. Cooking is the phase in which the curd is transferred to the hot water section of the cooker/stretcher. Typical water temperatures vary between 60 \({}^{\circ}\)C and 75 \({}^{\circ}\)C, and cooked curd temperatures vary between 55 \({}^{\circ}\)C and 65 \({}^{\circ}\)C. Stretching describes the mechanical treatment of the curd following cooking [2].  
On the other hand, traditional manufacture is based only on the artisanal cooking/stretching process of rennet curd made from raw milk [8]. Bacteria living in clustersand incorporated in the casein network mostly concentrate in the curd during its formation, and the rest of the microbiota leaves this step with the whey [9]. Stretching of the raw milk cheese curd in hot water substantially effects the distribution and viability of the present microbiota; however, it does not destroy it completely [10; 11]. Generally, the duration of the heat treatment is controlled empirically by cheese-makers based on the curd's melting and stretching properties [12]. In this context, many studies have pointed out the effect of the steaming and stretching phase on the microbial population of cheese curd, especially in relation to the presence of potentially pathogenic bacteria [13; 14; 15; 16]. With current demands for milder food processing conditions, it is a challenge to apply a minimally required heat load while inactivating the target microorganisms sufficiently [17]. Thus, quantitative studies are needed to understand the behavior of the microbial population over the course of raw milk/cheese processing and to assess consumer exposure to undesirable microorganisms from this type of raw milk cheese.  
That is why this study is focused on quantitative microbiological analysis in each processing step of raw milk steamed and stretched cheeses. The other aim was to provide a set of data for comparison with similar data from practice in order to help producers to improve the overall quality of these type artisan cheeses. In an effort to support the activity of native lactic acid bacteria (LAB), the culture Fresco DVS 1010 ([PERSON], Hersholm, Denmark) consisting of Lactococcus lactis subsp. lactis, Lc. lactis subsp. cremoris and Streptococcus salivarius ssp. thermophilus was added prior to raw milk coagulation.