Learning objectives
Module 2 of the course on Food Hygiene and Industrial Microbiology aims at understanding the effect of the presence and development of alterative and virtuous microorganisms in food. In particular, the knowledge concerning the main alterations originated by micro-organisms in food and the risk associated with the presence of pathogenic microorganisms in food, must be developed. The intrinsic, extrinsic and implicit factors that influence the development and survival of microorganisms in food must also be known. Knowledge of these aspects will provide the essential elements for understanding the role of micro-organisms in food production and their impact on food quality and safety. The use of this knowledge will also allow us to understand the principles of micro-organism control through physical, chemical and biological treatments or combinations thereof. The teaching aims to put the student in a position to draw conclusions about the effect of the presence and development of different microorganisms in food.
Prerequisites
no prerequisites are required. The topic of the introductory lectures will be the basic microbiology necessary to face the course.
Course unit content
The first lessons on general topics, necessary to provide the basis for understanding the most applicative parts of the course and to provide a common language. We will talk about the structure and functions of the microbial cell: bacteria and the prokaryotic cell, yeasts, molds and the eukaryotic cell, the mechanisms of transport of the nutrients necessary for the microbial cell. Then the microbial classification will be introduced according to the different sources of energy and the different uses of energy (chemotrophic and phototrophic; general description of the possible pathways of microbial degradation of glucose; aerobic / anaerobic, fermentations); Then the topics of growth and kinetics of microbial development will be addressed: Cell division; This introductory part will allow the student to orient himself in the study of microbial contamination and the effect of the development of alterative and virtuous microorganisms in different foods in order to understand the meaning of the presence of the different microorganisms associated with the different fresh and fermented products. The second part of the course will deal with the main pathogenic microorganisms of food and microbial alterations.
The third part of the course deals with the factors that influence the growth of microorganisms in food and the methods of their control in order to prevent or reduce the development of pathogenic and alterative microorganisms and to favor the development of virtuous microorganisms.
Full programme
Microbial cell: characteristics and functions, cell metabolism. Microbial nomenclature. The microbiological quality of food.
Microorganisms in food: bacteria, yeasts, molds
Food contamination: moments and sources. Process and contamination indicator microorganisms.
Protechnological, alterative, pathogenic microorganisms.
Negative aspects associated with the presence of some microorganisms, microbial degradation of food.
Negative aspects associated with the presence of some microorganisms, food microbial diseases.
Factors that influence the growth of microorganisms in food: temperature, pH, Aw, redox potential and oxygen availability, composition of a food
Growth and survival control: pH control, Aw control, use of low and high temperatures, packaging and protective atmospheres
Other technological interventions that affect microorganisms: treatments with ionizing radiation. Applications of high pressures and pulsed electric currents. Addition of food additives
Unfermented foods
Meat, fish, poultry, vegetables, fruit, milk and soft drinks
Bibliography
Pdf of course slides. Luca Cocolin Marco Gobbetti Erasmo Neviani
Microbiologia alimentare applicata
Casa Editrice Ambrosiana. Distribuzione esclusiva Zanichelli
2022. The text, available in university libraries, is to be understood as complementary and optional.
Teaching methods
The teaching will be carried out through lectures in the classroom with the help of slides that will represent teaching material also available online (on the elly page of the degree course) in pdf format for students. Video recordings of the lessons and / or other video material useful for students who find themselves following the Course remotely or asynchronously will also be uploaded on the Elly page of the Course. If it is not possible to hold the lessons in person due to force majeure, the lessons will be held in live streaming, recorded and uploaded on the elly platform, to guarantee students the opportunity to complete the training course. In the case of remote lessons, video materials and readings will be used to accompany what is covered in the lessons. For both modalities (in presence and distance), moments of confrontation with the students are foreseen to clarify and fix the most important topics.
Assessment methods and criteria
At the end of each part of the course during the course there are periodic lessons dedicated to classroom discussion with the students aimed at verifying the learning status.
The final assessment will be carried out through a single written exam for modules 1 and 2 of the Integrated Course, lasting 1.5 hours, with open questions (5), of which 1 question for each part of the course. Each question will be evaluated in 30th and the average of the marks, rounded up, of the questions will constitute the final mark. The sufficiency threshold will be reached if the average achieved is equal to or greater than eighteen thirty. If it is not possible to take written exams in person, the student's preparation will be verified by means of an oral exam in remote mode (teams).
Other information
Books for further information: Jay J.M., Loessner M.J., Golden D. A. “Microbiologia degli alimenti”. Springer (2009).
Galli Volonterio A. “Microbiologia degli alimenti”. Casa Editrice Ambrosiana (2005).
