Silvia Ruta

PhD Student
PhD in Agricultural, Food and Environmental Science - XXXIX Cycle
Tutor: Cinzia Caggia

August 2023 – Currently: PhD course in Agricultural, Food and Environmental Science, University of Catania; supervisor Prof.ssa Cinzia Caggia. Research project: “Microbiology in dairy processing and ageing and the role of wooden tools”. The main aim of research project are: i) estimate the contribution of microbial biofilms formed on “mastredda” to the curd acidification process and to the final organoleptic characteristics typical of Sicilian stretched-curd cheeses; ii) in-depth examination of the dynamics and metabolic activities of the microorganisms found in the rind using to provide insight into whether the microorganisms present on wooden shelves biofilms could be transferred to the rind and contribute to the ripening Sicilian cheeses.

September 2022 – August 2023: Research project collaborator, Soc. Coop. Agricola Bionatura.  Research project in collaboration with Corfilac (RG) investigating the effect of stretching temperatures during cheesemaking of pasta-filata cheeses on the survival of dairy pathogens. Key skills: isolation, phenotypic, and genotypic characterization of pathogenic bacteria from food samples; Research results elaboration and preparation of two posters for the American Dairy Science Association (Ottawa, June 25-28) and for the International Microbial Diversity Conference (Parma, September 26-29).

April 2022 – June 2022: Erasmus+ Traineeship, APC Microbiome Ireland. Research project investigating the microbial and phage population in Pecorino Siciliano PDO cheese. Key skills: cultivation of lactic acid bacteria from food samples: understanding of selective and differential media and growth conditions; differentiation between different lactic acid bacteria based on phenotypic and genotypic characteristics; isolation of bacteriophage and propagation; extraction of DNA from food samples and individual microorganisms; PCR and agarose gel electrophoresis; presentation research findings; writing a research report.

November 2021 – December 2021: Undergraduate Internship, Experimental Zooprophylactic Institute of Sicily – A. Mirri. Key skills: total bacterial counts by flow cytometry; urea & staphylococcus analysis of milk. Examining non-conformity cases in certified products; verification of the tracking and traceability of food.

January 2021 – March 2022: Tutorship activities, University of Palermo. Didactic tutoring activities in Food Microbiology and Animal Science.

2020 – 2022: Master’s Degree (Entrepreneurship and Quality in the Food System (IQSA)) - University of Palermo. Experimental thesis: “Microbiological characterisation of lactic acid bacteria involved in the production process of PDO Provola dei Nebrodi cheese”; supervisor Prof. Antonio Alfonzo. Final mark:110/110 cum Laude.

July 2017 – January 2018: Undergraduate Internship, Leocata Mangimi S.P.A. Key skills: welfare assessment of dairy cows; forages evaluation and sampling; unifeed evaluation and particle size analysis; formulation of diets for dairy cows.

2015 – 2019: Bachelor’s Degree (Agricultural and Technological Science) - University of Catania. Thesis: ‘Effects of feed particle size on the digestibility of lactating dairy cow diets’, supervisor Prof. Marco Bella. Final Mark: 110/110.

2010 – 2015: Scientific High School Diploma, Istituto di Istruzione Secondaria Superiore Archimede - Rosolini.

Activities of the research project:

  1. Discover whether mastredda effectively transferred microorganisms to the curd during the cheesemaking process of Provola dei Nebrodi PDO and Ragusano PDO cheeses by dependent and independent culture approaches. Those two kinds of cheese have been selected because in Provolola dei Nebrodi PDO the mastredda is used only for curd acidification, whereas in Ragusano PDO mastredda is used for curd acidification and moulding (after the stretching process). Therefore, in these two kinds of cheese "mastredda" biofilm could contribute differently in relation to the quantity of microorganisms transferred and the time the curd lise-on;
  2. Estimate the contribution of each species transferred from mastredda to the curd and to cheese investigating biochemical modifications. In detail: the technological traits of the strains isolated will be carried out. In addition, transcriptome will be detected in order to highlight carbohydrate fermentation pathways (in curd after acidification) and the proteolytic and lipolytic activity will be investigated in differents ripening stages;
  3. Discover if microorganisms present on wooden shelves biofilms could be transferred to the rind and to explore their contribute to the ripening of a Sicilian cheese listed in the foreword through a culture-independent approach and metatranscriptome analysis of proteolytic and lipolytic genes.


- Ruta, S., Murray, M., Kampff, Z., McDonnell, B., Lugli, G. A., Ventura, M., ... & Mahony, J. (2023). Microbial Ecology of Pecorino Siciliano PDO Cheese Production Systems. Fermentation9(7), 620.


-  Factors affecting food security in raw-milk Pasta-filata cheese manufacture; 7th International Conference on Microbial Diversity: Agrifood microbiota as a tool for a sustainable future; September 26-29, 2023 – Parma, Italy.

   The poster won the awards as best poster within all topic session.

- Effect of stretching temperature on the growth of four dairy pathogens bacteria in raw-milk Pasta-filata cheese manufacture; ADSA Annual Meeting, June 25- 28, 2023 – Ottawa, Ontario, Canada.