18459 - Protection of Food Crops ( Corso Integrato) - Postharvest Pathology of Food Crops

Learning outcomes

By the end of the course, students will be able to recognize the main causes of losses in postharvest products and commodities, distinguishing disorders of biotic origin from those caused by adverse environmental factors, and to identify the main causal pathogens. They will also be able to apply integrated biological protection strategies, assessing their sustainability and their effects on product quality and storability.

Course contents

1. Chilling injury (3 hours)

Practical importance of chilling injury and limitations to the use of the cold chain. Classification of fruit and vegetable species according to their susceptibility to low temperatures. Symptoms and physiological and cytological alterations associated with chilling injury. Factors affecting susceptibility and prevention strategies. Observation and discussion of images showing the main symptoms of chilling injury.

Knowledge and skills acquired in the teaching unit

• understands the effects of low temperatures on metabolism and the main physiological and cellular mechanisms involved in chilling injury;
• understands differences in the susceptibility of plant products to chilling injury in relation to geographical origin, cell membrane composition, and mechanisms regulating reactive oxygen species (ROS);
• can recognize the main symptoms of chilling injury in postharvest fruit and vegetable products;
• knows the main strategies for preventing or limiting the occurrence of chilling injury.

  2. Integrated protection of plant products (7 hours)

  Integrated postharvest protection techniques during storage, transport, and distribution, based on the use of physical, chemical, and biological methods.

  2.1 Physical methods

  High temperatures: application of heat treatments (hot water and hot air), effects on the host (plant product) and on pathogens.

  Low temperatures (refrigeration): importance of the cold chain in the storage and distribution of fresh plant products, effects on the host (plant product) and on pathogens.

  Oxygen and carbon dioxide: importance of controlled atmosphere, dynamic controlled atmosphere, and modified atmosphere in the storage and distribution of fresh plant products, effects on the host (plant product) and on pathogens.

  Ethylene removal: influence of ethylene on product ripening and senescence, removal techniques, effects on the host (plant product) and on pathogens.

  Environmental hygrometry (relative humidity): importance and management of relative humidity during storage of plant products, effects on the host (plant product) and on pathogens.

  Low-dose ultraviolet light: methods of application, effects on the host (plant product) and on pathogens.

  Ionizing radiation: sources, safety of use and application limits, effects on the host (plant product) and on pathogens.

  2.2 Chemical methods

  Disinfectants: main types of disinfectants used on plant products, application methods, efficacy, limitations, and undesirable effects.

  Plant protection products and food additives: classification, hazard classes, technical and hygiene-related limits, modes of action, formulation types, and application methods. Regulations on residues and issues related to their presence in fresh and stored products.

  2.3 Biological methods

  Biological control: use of natural substances (origin, activity, undesirable effects, and application limits) and antagonistic microorganisms (bacteria, yeasts, and fungi); modes of action, compatibility with other protection methods, and application limits. Induction of host resistance.

  Knowledge and skills acquired in the teaching unit

• understands the principles of integrated protection and its role in controlling postharvest diseases;
• knows the main applications of physical methods and their effects on the host (plant product) and on pathogens;
• knows the main disinfectants that can be used on plant products and their role in controlling postharvest rots and microorganisms pathogenic to humans;
• knows the possible uses of plant protection products in postharvest and the issues related to the development of resistance, environmental impact, and residues in products;
• knows the applications, modes of action, and limitations of biological control of postharvest pathogens;
• is able to assess the advantages and limitations of the different protection methods and their possible integration into sustainable postharvest disease management strategies.

  Special section (16 hours)

  Study of the main postharvest pathosystems of fruit and vegetable products:

• pome fruit pathosystems;
• stone fruit pathosystems;
• kiwifruit pathosystems;
• grape pathosystems;
• strawberry pathosystems;
• tomato pathosystems;
• potato pathosystems;
• · onion pathosystems;
• leafy vegetable pathosystems.

  For each pathosystem, the following topics are covered:

• importance and distribution of the main diseases and disorders and their impact on qualitative and quantitative losses;
• etiology and characteristics of the main causal agents;
• symptomatology and diagnosis, including the observation of images and samples of fruit and vegetable products;
• life cycle and epidemiology of the main pathogens;
• host-pathogen-environment interactions and their influence on the onset and development of postharvest diseases;
• main abiotic disorders and related predisposing factors;
• prevention and integrated protection strategies.

  Knowledge and skills acquired in the teaching unit

• knows the main postharvest pathosystems of fruit and vegetable products and is able to recognize the main diseases and disorders of biotic and abiotic origin;
• knows the life cycle and epidemiology of the main pathogens and understands the role of host-pathogen-environment interactions in the onset and development of postharvest diseases;
• knows the main integrated protection strategies against postharvest diseases and is able to assess and adapt their application according to the pathosystem and storage conditions.

Readings/Bibliography

Patologia dei prodotti e delle derrate:

Files presented during the lectures and provided as copies to students attending the course.

V. De Cicco - P. Bertolini - M.G. Salerno- Patologia postraccolta dei prodotti vegetali. Piccin Nuova Libraria S.p.A., Padova. (l'importo dei diritti d'autore è devoluto alla Società Italiana di Patologia vegetale - SIPaV)

Atlases for disease identification:

Tonini G. Atlante delle alterazioni microrganiche postraccolta (pomacee e drupacee). Bayer s.p.a, Milano,1996. (Consultabile c/o Biblioteca "G. Goidanich"

Snowdon A.L. A colour atlas of postharvest diseases & disorders of fruit & vegetables. Vol. 1 & 2 . Wolfe Scientific ed. London, 1990. (Consultabile c/o Biblioteca "G. Goidanich").

Also available at the following link: http://books.google.it/books?id=WK-Scwl9skYC&pg=PA335&lpg=PA335&dq=susceptibility+to+potato+black+spot+measured&source=bl&ots=wSIuAJfb1g&sig=SlR6ErBMOjfl425PwbPFjgF-YFc&hl=en&sa=X&ei=GZRKT_OvEIPCtAa_x8yUBQ&redir_esc=y#v=onepage&q=susceptibility%20to%20potato%20black%20spot%20measured&f=false

Websites:

[http://postharvest.ucdavis.edu/PF/] → Produce facts →Choose the language (English, Francais, Espanol) → fruits /vegetables species → Link to produce photo album (miglior sito web)

Si consiglia di osservare i sintomi, causati dallo stesso agente patogeno o fattore abiotico , su più specie di frutti/ortaggi. Nel testo di “Patologia postraccolta” sono riportate le denominazioni delle malattie anche in lingua inglese.

AAVV. Identifying and Controlling Postharvest Tomato Diseases in Florida - http://edis.ifas.ufl.edu/

AAVV Market Diseases of Apples, Pears, and Quinces. http://postharvest.tfrec.wsu.edu/market_diseases.html#breakdown

C. L. Xiao. Postharvest Diseases of Apples and Pears - A Guide to Diagnosis and Control. http://decay.tfrec.wsu.edu/

Teaching methods

The course includes classroom lectures supported by PowerPoint presentations, which are made available to students in PDF format on the VIRTUALE platform. During the lectures, the topics will be actively discussed with students through the analysis of case studies, practical examples, and technical-scientific videos related to the subjects covered.

The lectures will be complemented by practical sessions aimed at recognizing the main postharvest diseases of fruit and vegetables. Contributions from professionals working in the field of postharvest storage and management of fruit and vegetable products are also planned, with the aim of exploring the applied aspects addressed during the course.

Students will also be encouraged to participate actively in the lessons through classroom presentations and discussion of issues addressed in scientific articles selected by the lecturer and relevant to the course topics.

Assessment methods

A single overall mark is awarded for both courses.

The examination for the course PATHOLOGY OF PRODUCTS AND COMMODITIES consists of a written test comprising 32 multiple-choice questions, with only one correct answer to each question. One point is awarded for each correct answer; there is no penalty for incorrect or unanswered questions. The time allowed is 40 minutes.

The written test is administered, subject to the availability of facilities, on computers in the computer room or, alternatively, in paper format in a classroom communicated through AlmaEsami. The test is marked immediately after completion.

The test is passed with a minimum score of 18/32. The score obtained corresponds to the grade expressed on a thirty-point scale; a score of 31/32 or 32/32 is awarded 30/30 cum laude.

Students with specific learning disabilities (SLD/DSA) or other certified educational needs are invited to request any necessary accommodations at least one week in advance by contacting the lecturer and the University of Bologna DSA Office, in accordance with the University's procedures.

Registration for the examination through AlmaEsami is compulsory. Students who decide not to take the examination on the booked date are required to cancel their registration by the closing date of the registration list.

The course, teaching materials, and written examination questions are in Italian. Erasmus students may take the examination in English.

Teaching tools

PC, video projector, plant material showing symptoms of postharvest diseases, audiovisual material.

Office hours

See the website of Annamaria Mincuzzi