Food spoilage

• What is the main focus of this unit on food spoilage?

  Understanding food spoilage, its causes, and changes in different foods
• What are the objectives of studying this unit on food spoilage?

  To explain spoilage, describe chemical changes, and discuss spoilage of different foods
• When is food considered spoiled?

  When it becomes unacceptable for consumption based on organoleptic characteristics
• What are the manifestations of microbial deterioration in food?

  Changes in appearance, texture, odour, flavour, or slime formation
• How can microbial transformations be classified?

  As positive or negative based on their effects on food
• What are some examples of positive microbial transformations?

  Cheese, yoghurt, and wine
• What are the negative aspects of microbial growth in food?

  Food deterioration and spoilage, leading to decay and food poisoning
• What is the main basis of microbial food spoilage?

  The release of enzymes by microorganisms into the surrounding liquid
• What types of changes can spoilage cause in food?

  Physical, chemical, or biological changes
• What are the factors that lead to food spoilage?

  Microbial growth, enzyme activity, infestation, chemical changes, physical changes, foreign bodies, and physical abuse
• How does individual perception affect the classification of spoiled food?

  It is subjective and varies based on taste preference, ethnic origin, and family background
• How can foods be categorized based on their perishability?

  Into non-perishable, semi-perishable, and perishable foods
• What are examples of non-perishable foods?

  Cereals, pulses, and sugar
• What defines semi-perishable foods?

  Foods that can survive without spoilage for a few weeks or months
• What are examples of perishable foods?

  Milk, meat, fish, poultry, and most fruits and vegetables
• Why is there no absolute classification of food spoilage?

  Because environmental conditions like temperature and humidity affect spoilage
• What is the significance of understanding chemical changes in food spoilage?

  It helps in practical applications in daily life and academic knowledge
• What is often not apparent in spoiled food?

  The internal changes that may cause ill health
• How do the chemical changes in food due to spoilage depend on its composition?

  They vary based on whether the food is plant-based or animal-based
• What are the main types of carbohydrates found in foods?

  Monosaccharides, disaccharides, oligosaccharides, and polysaccharides
• What happens to carbohydrates during spoilage?

  Bacteria break them down to monosaccharides, causing softening or liquefaction
• What are fats composed of?

  Esters of glycerol and fatty acids
• How do microorganisms affect fats in food?

  They degrade fats into glycerol, free fatty acids, ketones, and alcohols
• What are proteins composed of?

  Amino acids combined by peptide linkages
• What is putrefaction?

  The foul smell produced by anaerobic degradation of amino acids
• What is decay in the context of food spoilage?

  Aerobic degradation of amino acids
• How does the nutrient composition of food affect spoilage?

  Different foods have varying nutrient contents, leading to different spoilage processes
• What is the focus of the next section in the study material?

  Spoliage of different foods and the organisms causing it
• What is the primary composition of meat?

  Muscular tissue containing essential nutrients and high water content
• What influences the spoilage of meat?

  The initial contamination of the animal and hygienic conditions during slaughter
• What happens to the pH of meat after slaughter?

  The pH drops from around 7.0 to 5.6 due to lactic acid formation
• What is the process of stiffening in meat known as?

  Rigor mortis
• What is the desired action of enzymes in meat tenderization called?

  Ripening
• What happens to meat if autolysis is not stopped?

  It becomes sour
• What are the important factors that lead to the growth of microorganisms in meat?

  • Initial microflora
  • pH levels
  • Oxidation-reduction potential
  • Temperature
• How does the initial microbial load affect meat preservation?

  A higher initial microbial load reduces the keeping time of meat
• Why are hygienic conditions important for animals before slaughter?

  They help reduce the proliferation of microorganisms in stored meat
• What happens to the pH of meat after slaughter?

  The pH drops from around 7.0 to 5.6
• What causes the pH of meat to remain around 7.0 after slaughter?

  Rapid use of glycogen due to stress or excitement
• What is putrefaction in the context of meat spoilage?

  Decomposition of foods due to microbial action