Fish Microbiology and Quality Assurance (2+2)

Unit 2 - Growth and survival of microorganisms in food

2.1.5. Antimicrobial constituents and barriers
All foods have one or the other mechanism to prevent or limit potentially damaging effects by microorganisms through protective physical barriers to infection (Ex. skin, shell, and husk) and antimicrobial components. Natural covering of some foods provide excellent protection against entry and subsequent damage by spoilage microorganisms. These include outer covering of fruits, outer shell of egg, skin covering of fish and meats.

The outer covering is usually composed of macromolecules and these are resistant to degradation and create inhospitable environment for microorganisms due to low aw and shortage of readily available nutrients.The antimicrobial substances such as short chain fatty acids in animal skin and essential oils in plant surfaces help to prevent entry of microorganisms.

Physical damage to outer barrier allows microbial invasion and cause spoilage. Some foods are resistant to attack by microorganisms and remain stable due to the presence of naturally occurring substances which have antimicrobial property. Many plant species possess essential oils which are antimicrobial.

Antimicrobial property in certain foods