C6 Fermented meat

Question 1

What are the factors in fermented meat that inhibits microbial growth?

Answer 1

• Lactic acid produced by LABs reduce pH and water activity
• Addition of salt lower water activity
• Nitrites and nitrates inhibits microorganisms

Question 2

What is the ideal meat and fat ratio for fermented sausage?

Answer 2

• 2:1

Question 3

What are the bacterial starter cultures used for fermenting sausage?

Answer 3

• Lactobacillus (heterofermentative) and pediococcus (homofermentative): For acidulation and optimal flavor development
• Micrococci: Resistant to acid environment

Question 4

What are the advantages of using starter culture for fermenting sausages?

Answer 4

• Acidification
• Production of known enzymes: catalase, protease, lipase
• Avoidance of discoloration
• Bacteriocin production.

Question 5

What causes the formation of biogenic amines in fermented meat? How do prevent it?

Answer 5

• Formed by the decarboxylation of amines by microorganisms possessing decarboxylase activity
• Prevented by using starter cultures with negative decarboxylase activity such as Lb sakei.
• Some biogenic amines include cadaverine, putrescine, spermidine, histamine.

Question 6

What are the changes incurred by fermentation on meat?

Answer 6

• Proteolysis: Proteolytic enzymes of LAB and endogenous proteinase cathepsin D hydrolyzes peptides into amino acids.
• Lipolysis: Muscle lipase and microbial lipase cause the hydrolysis of fats, releasing free fatty acids, aldehydes, ketones, alcohols and esters. MCFA precursors of aroma compounds, SCFA provides strong cheesy odors
• Catalase activity: H2O2 produced from lactobacillus interfere with sensory properties, cause discoloration and lipid oxidation. Coagulase negative staphylococci produce catalase and superoxide dismutase to prevent the formation of H2O2.
• Flavor and aroma formation produce aroma compounds.

Question 7

What are some coagulase negative staphylococci?

Answer 7

• S. carnosus and S. xylosus