WHAT IS SPOILAGE? • Spoilage is the process in which food deteriorates to the point in which it is not edible to humans, or its quality of edibility becomes reduced OR • Any change which renders a product unacceptable for human consumption. • Complex event in which a combination of microbial and biochemical activities may interact. • One of the major reason that led to preservation. FACTORS DETERMINING THE SPOILAGE • Microbial colonization depends on – characteristics of product – The way processed – The way stored • Factors are characterized into four: – Intrinsic parameters – Extrinsic parameters – Modes of preservation and processing – Implicit parameters INTRINSIC PARAMETERS • Physical, chemical and structural properties. • Inherent in the food itself. • Important factors include water activity, acidity, redox potential, available nutrients and natural antimicrobial substances. EXTRINSIC PARAMETERS • Factors in the environment where food is stored • Temperature, humidity and atmosphere conditions. MODES OF PRESERVATION AND PROCESSING • Physical or chemical treatment • Change characteristics of food product • Determine the micro flora associated with the product IMPLICIT PARAMETERS OR MICROBIAL INTERFERENCE • These are the result of the development of synergistic or antagonistic microbes • It can be said as the destruction of one organism by another species releasing H2 O2 , bacteriocin and other di-acetyl compounds. • Synergistic: Production or availability of essential nutrients due to the growth of certain organisms, which allow the growth of another group which were otherwise unable to grow. • Antagonistic : Competition for essential nutrients, changes in pH value or redox potential or formation of antimicrobial substances. TYPES OF SPOILAGE Two types of Spoilage: • Microbial spoilage • Non- Microbial Based on rate of spoilage: • Highly perishable – Meat, fish, poultry, eggs, milk, most fruits and vegetables. • Semi perishable – Potatoes, some apple varieties, nutmeats • Stable or non-perishable – Sugar, flour, dry beans SPOILAGE OF FRUITS AND VEGETABLES • The organism responsible for taints are acid tolerant bacteria: – Lactobacillus spp. • Deterioration can be caused by action of animals, birds, bruising, wounding, cutting, freezing, dessication or other mishandling and growth of microorganisms; environmental conditions, contact with spoiled foods. • Microbial spoilage maybe due to: – Plant pathogens acting on stems, leaves, flowers or roots – Saprophytic organisms • Types of spoilages: – Baterial soft rot • Caused by Erwinia carotovora, ferment pectins • Pseudomonas marginalis, Bacillus and Clostridium cause water soaked appearance, a soft, mushy consistency and bad odour. – Anthracnose • Caused by Collectotrichum lindemuthianum. • Spotting of leaves and fruits – Black mold rot • Caused by Aspergillus niger • Dark brown to black masses of spores of the mold termed as smut • Rhizopus soft rot – Caused by species of Rhizopus – Soft and mu