Food microbiology

Sven-Olof Enfors

KTH School of Biotechnology

Stockholm 2011

Content

1. Introduction . .............................................................................................................................. 1

2. The ecological basis of food spoilage ................................................................................... 5

2.1 The microflora......................................................................................................................... 5

2.2 The physico-chemical properties......................................................................................... 8

2.3 Main chemical spoilage reactions ..................................................................................... 15

3. Spoilage of different types of food ...................................................................................... 23

3.1 Meat and fish ........................................................................................................................ 23

3.3 Carbon dioxide storage and vacuum packages............................................................. 27

3.4 Milk .......................................................................................................................................... 32

3.5 Egg............................................................................................................................................ 33

3.6 Fruits and vegetables .......................................................................................................... 34

3.7 Cereals .................................................................................................................................... 36

3.8 Preserved foods ................................................................................................................... 37

4. Food borne pathogens .......................................................................................................... 39

4.1 Microbial food intoxications ............................................................................................... 40

4.2 Food borne infections ......................................................................................................... 45

5. Food preservation .................................................................................................................. 53

5.1 Heat sterilisation and pasteurisation .................................................................................. 53

5.2 Chemical preservation......................................................................................................... 65

6. Fermented foods ..................................................................................................................... 73

6.1 Beer brewing ........................................................................................................................ 74

6.2 Fermented milk products.................................................................................................... 81

6.3 Fermented meat products ................................................................................................. 88

6.4 Fermented vegetables ......................................................................................................... 89

7. Subject index .......................................................................................................................... 91