FOOD MICROBIOLOGY LABORATORY STUDIES
Learning outcomes of the course unit
The aim of the course is to give to the student a deep theoretical and practical knowledge on the phenotypic and genotypic methods mainly used for the qualitative and quantitative analysis of microorganisms in foods. In particular, this course wants to make the student independent about:
bibliographic research about the product studied (raw material, characteristic steps of product processing, storing, contamination risk, quality and food safety criteria…)
identification of the microorganisms (useful or harmful) for which is necessary to project an analysis in different categories of food
evaluation of knowledge, instrumentation and material at disposal
management, organization and hand labor in practical analysis
analysis and interpretation of results
To reach the purposes, the knowledge gained in General microbiology and Food microbiology and Industrial microbiology courses is necessary. A good knowledge of English, together with the use of on-line search engine, allow to enter to a wide documentation. Moreover, the use of Microsoft Word and Excel programs can be useful for a right expression of results.
Course contents summary
Role of microorganisms in foods and meaning of contamination: microorganisms indicator of typical, quality and safety
Good laboratory practices
Set up of a food microbiology laboratory: instrumentation required and its use
Sterility concept and methods to sterilize. Autoclave working
Media for cultivation of microorganisms in foods (liquid, solid, general, elective, selective, differential…)
Microbiological quantitative and qualitative analysis: methods of analysis and sample preparation
Preparation of cultural media and sterilization of material
Butter analysis. Sampling following FIL IDF norm. Determination of total microflora, total coliforms, yeasts and moulds. Methods of deep and double layer inoculation
Ice cream analysis. Sample rivification. Determination of mesophilic and thermophilic microflora, total coliforms and E. coli. Research of S. aureus. Use of selective and differential media
Soft drink and fruit juice analysis. Determination of yeasts, moulds and lactic acid bacteria. Use of surface inoculation method
Meat analysis. Faecal streptococci research by selective media
Drinking water and tap water analysis. Determination of total microflora and Pseudomonas aeruginosa research by filter membranes technique
Vegetables analysis. Research of total microflora, yeasts and moulds by selective media
Fish analysis. Research of total coliforms and E. coli by using differential media
DNA extraction from food matrix. DNA quantification and evaluation by spectrophotometer
Antonietta Galli Volonterio. Microbiologia degli Alimenti. Casa Editrice Ambrosiana.
Regione Lombardia. Metodi raccomandati per analisi microbiologiche non normate di alimenti. www.regione.lombardia.it
Food Microbiology: Foundamentals and Frontier. Edited by Doyle P.M.,Beuchat, L.R., Monteville, T.J., 2th ed. ASM Press, Washington, D.C.
The course of 3 cfu is characterised by laboratory lessons, for a total amount of 36 hours. In the laboratory the students have at disposal an own working space and the instrumentation necessary to the analysis. During every lesson the microbiological problem related to a food product is discussed, its analysis and the correct use of material and instrumentations are showed. Moreover, the results obtained in previous analysis are discussed.
The students are evaluated through a practical exam following the objectives of the course. This exam is constituted by a preliminary bibliographic research about a food product chosen by the student. The individuation of the microbiological problematic linked to this food lead to the choice of the right methodology of analysis and to the organization of this by preparation of the material. During the analysis the student has to show the control of the microbiological main concepts and a good manual work, and has to be able to interpret and express the results in a correct way. Moreover, the student has to present a notebook with all the analysis done during the course, including the exam one.