Giáo trình công nghệ sau thu hoạch - Chương 4

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Giáo trình công nghệ sau thu hoạch - Chương 4 CHƯƠNG 4 BỆNH SAU THU HOẠCH10/23/2009 1 Th.S Truong Thi My Linh Harvesting, transport, marketing etc.10/23/2009 2 Th.S Truong Thi My LinhBệnh sau thu hoạch?Thường xuất hiện trong giai đọan giữa thu hái vàhòan thiện sản phẩm, trong quá trình bảo quản ,vận chuyển, tại người bán buôn, bán lẽ...Là kết quả sự lây nhiễm các sản phẩm trước khinó được chế biến hoặc đến tay người tiêu dùng•Bệnh sau thu hoạch thông thường xuất hiện10/23/2009 3 Th.S Truong Thi My LinhPost-harvest diseases(PDs) of fruits and Vegetables Symptoms (triệu chứng) of PDs Soft rots and watery rot caused by Geotrichum, Rhizopus, Sclerotinia, Pseudomonas and Erwinia Brown rots caused by Phytophthora, Monilinia, Botrytis etc Dry rots caused by largely Fusarium spp.10/23/2009 4 Th.S Truong Thi My LinhPost-harvest diseases(PDs) of fruits and vegetablesInfection timing (sự lây nhiễm) and methods of PDsAttacks the actively growing plants and then develop on the crop in storage Botrytis cinerea on grapes, apples and pear Sclerotinia sclerotiorum on green beanInfects the crop at early stage but remain latent and cause decay only when the crop ripen or when it has been stored for some time Botryosphaeria dothidea on apples and pears Anthracnose fungusAttacks the crops only after harvest Penicillium spp. on apples, pears, citrus fruits, garlic etc.10/23/2009 5 Th.S Truong Thi My LinhPost-harvest diseases(PDs) of fruits and Vegetables Infection type (caùc daïng laây nhieãm) of PDs Through intact surface : Anthracnose fungi Through intact surface from adjoining diseased fruits/vegetables : Botrytis cinerea Through injury : Geotrichum, Penicillium, Rhizopus, Thieloviopsis etc.10/23/2009 6 Th.S Truong Thi My LinhPost-harvest diseases(PDs) of fruits and Vegetables Wounds(injuries) is very important in PDs Caùc yeáu toá khaùng Toån thöông Vi khuaånPhaûn öùng cuûa chuû theå Maàm beänh10/23/2009 7 Th.S Truong Thi My Linh Causes of mechanical injuries • Poor harvesting practices and handling • Unsuitable field or marketing containers and crates, which may have splintered wood, sharp edges, poor nailing or stapling; • Overpacking/underpacking of field or marketing containers • Careless handling, such as dropping or throwing or walking on produce and packed containers during the process of grading, transport or marketing10/23/2009 8 Th.S Truong Thi My Linh Physiological injuries also predispose (daãn ñeán) fruits and vegetables to pathogens (mầm bệnh) • Too low storage temperature • Too high temperatures • Poor ventilation( söï thoâng hôi) • Volatile compounds( hôïp chaát deã bay hôi)10/23/2009 9 Th.S Truong Thi My Linh The forms of injuries • Splitting of fruits or roots and tubers caused by dropping • Internal cruising, not visible externally, caused by impact; • Superficial grazing or scratches affecting the skins • Crushing of leafy vegetables and other soft produceEach injury provide entry for penetration of postharvest pathogens10/23/2009 10 Th.S Truong Thi My Linh Injuries cutting through or scraping away the outer skin of produce• Provide entry points for moulds and bacteria causing decay• Increase water loss from the damage areas;• Cause an increase in respiration rate and thus heat production10/23/2009 11 Th.S Truong Thi My Linh Bruising( veát thaâm tím) injuries, which leave the skin intact (khoâng bò ñuïng chaïm) and may not be visible externally (beân ngoaøi) cause:• Increased respiration rate ...