Explain the microorganisms involved in the spoilage of bread, fruits and vegetables, meat, fish, eggs and milk.

1. 1 · Open in two lines. Each food is spoiled by the microbes that suit its pH, moisture and nutrients. Moist neutral foods spoil through bacteria; acid, sweet or dry foods through yeasts and moulds.
2. 2 · Bread.
   • Mouldiness: Rhizopus (black), Penicillium (green), Neurospora (pink).
   • Rope: Bacillus subtilis; red bread: Serratia.
3. 3 · Fruits and vegetables.
   • Fruits: Penicillium, Botrytis, Rhizopus, Aspergillus; anthracnose of mango (Colletotrichum).
   • Vegetables: bacterial soft rot by Erwinia and Pseudomonas.
4. 4 · Meat and fish.
   • Meat: surface slime by Pseudomonas; deep putrefaction by Clostridium.
   • Fish: Pseudomonas and Shewanella; TMAO → TMA gives the fishy smell.
5. 5 · Eggs and milk.
   • Eggs: green rot (Pseudomonas), black rot (Proteus), red rot (Serratia); mould pin spots.
   • Milk: souring (lactic acid bacteria), gas (coliforms), ropiness (Alcaligenes), sweet curdling (Bacillus cereus).
6. 6 · Draw a summary table. [Table: food | organism | type of spoilage | signs]
7. 7 · Nutrition link. In an institutional kitchen, chill bacteria-prone foods, keep bread and pickles dry, and throw away ropy bread or rotten eggs.
8. 8 · Close in one line. Matching the preservation method to the spoiler keeps each food safe for longer.

Scoring tip: Learn one organism and one sign for each food; a neat table carries most of the marks.