Option F:Microbes and Biotechnology

F.4 Microbes and Food Production

F.4.1 Explain the use of Saccharomyces in the productions of beer, wine, and bread

(grain)

(Anaerobic fermentation)

F.4.1 Explain the use of Saccharomyces in the productions of beer, wine, and bread

(grain)

(Anaerobic fermentation)

F.4.1 Explain the use of Saccharomyces in the productions of beer, wine, and bread

• Yeast feeds off of starch in flour which gives of CO2 using anaerobic respiration

• This makes dough rise• High temperatures in oven kill yeast and evaporate ethanol

F.4.2 Outline the production of soy sauce using Aspergilus oryzae

• Ingredients: soy beans, wheat, salt, and flour

• Soy beans are fermented using Asperigillus oryzae

• The mold is added to steamed soy beans and roasted wheat

• Carbohydrates fermented to alcohol and lactic acid

• A mash is obtained• Proteins broken down into

dipeptides/amino acids• Colour due to 6-8 months maturation

process• Sauce is pasteurised

F.4.3 Explain the use of acids and high salt or sugar concentrations in food preservation

Weak acids: lowers intracellular pH of microbe and prevents its growth (acetic acid and pickled onions)

High salt: creates high osmotic potential which kills microbes by drawing out water (salted meat)

High sugar: creates high osmotic potential which kills microbes by drawing out water (preserved fruits)

F.4.4 Outline the symptoms, method of transmission and treatment of one named example of food poisoning

Food poisoning

Symptoms Transmission Treatment

Salmonella

Ciguatera

Clostridium botulinim

• Undercooked contaminated food

Diarrhea, fever, cramps, Reiter’s syndrome

• Antibiotics• Oral rehydration• Eating Lactobacillus

• Toxins from algae/dinoflagellates/protists in fish

Nausea, vomiting, diarrhea, headaches, vertigo

• No effective treatment

• Foodborne infectionSkeletal muscle paralysis, blurred vision, difficulty speaking and breathing

• Antitoxin• Intensive respiratory

care• Immunoglobulin