Information Package / Course Catalogue
Starter Cultures
Course Code: SU256
Course Type: Area Elective
Couse Group: Short Cycle (Associate's Degree)
Education Language: Turkish
Work Placement: N/A
Theory: 2
Prt.: 0
Credit: 2
Lab: 0
ECTS: 4
Objectives of the Course

This course aims to teach students the importance of pure culture in terms of dairy products, nutrition and health, the production and preparation of pure cultures, and their use during production.

Course Content

Knowing and evaluating the importance of pure culture in dairy product production

Name of Lecturer(s)
Learning Outcomes
1.To have knowledge about the definition, classification and usage areas of starter cultures.
2.Recognizes starter cultures used in dairy products. Knows the microbiological properties, growth conditions and metabolic activities of starter cultures.
3.Explains the production, multiplication and protection methods of starter cultures. Compares the differences between probiotic and prebiotic microorganisms and starter cultures.
4.Understands the morphology of bacteriophages, their mechanism of infection, and the problems they cause in dairy operations; explains phage defense strategies.
5.Explains the symbiotic relationship between yogurt bacteria (L. bulgaricus and S. thermophilus); explains how they promote each other’s growth.
Recommended or Required Reading
1.Lactic Acid Bacteria in Dairy Industry. KILIÇ,S. 2010.
2.Pure Culture in Dairy Industry. KILIÇ,S. 2001
3.Food Microbiology. ERKMEN, O.
Weekly Detailed Course Contents
Week 1 - Theoretical
Definition, history, importance, and applications of starter cultures in the dairy industry
Week 2 - Theoretical
General characteristics of lactic acid bacteria: Gram-positive, catalase-negative, facultative anaerobic and aerobic; taxonomy and morphology
Week 3 - Theoretical
Homofermentative and heterofermentative lactic acid bacteria: Lactococcus lactis subsp. lactis, L. cremoris, L. diacetylactis; metabolic characteristics and fermentation products
Week 4 - Theoretical
Mesophilic and thermophilic cultures: optimal growth temperatures, L. delbrueckii subsp. bulgaricus, S. thermophilus, L. acidophilus, L. helveticus
Week 5 - Theoretical
The primary functions of starter cultures: lactic acid production, flavor and aroma development (diacetyl, acetaldehyde, esters), contributing to curd formation, and extending shelf life
Week 6 - Theoretical
Yogurt bacteria: The symbiotic relationship between L. bulgaricus and S. thermophilus; mutual stimulation via free amino acids, formic acid, and CO2
Week 7 - Theoretical
Types of starter cultures: single-strain, multi-strain, and mixed-strain cultures; O, L, D, and DL cultures; which culture type is used in which product
Week 8 - Theoretical
Commercial culture forms: liquid cultures (1 week at 5°C), powdered cultures (spray-dried and freeze-dried), frozen cultures (-35°C, -196°C); DVS (direct-vat-set) cultures
Week 9 - Theoretical
Methods for preparing starter cultures: preparation of the primary culture, intermediate culture, and bulk culture; milk selection, propagation steps, and aseptic conditions
Week 10 - Theoretical
The use of starter cultures in cheese production; culture combinations based on cheese type; inoculation rates (hard cheese: 0.2%, semi-hard cheese: 0.5–1%, soft cheese: 1–2%)
Week 11 - Theoretical
The role of starter cultures in cheese ripening: glycolysis, proteolysis, and lipolysis; the mechanism of flavor and aroma formation
Week 12 - Theoretical
Bacteriophages: definition, morphology (head-tail structure), infection cycle (lytic and lysogenic pathways); phage-related issues in dairy operations and prevention strategies
Week 13 - Theoretical
Protective cultures, biocontrol, and the use of starter cultures in food safety
Week 14 - Theoretical
Probiotic starter cultures (L. acidophilus, Bifidobacterium spp.); recombinant rennet; innovative culture applications and future trends in the dairy industry
Assessment Methods and Criteria
Type of AssessmentCountPercent
Assignment1%5
Quiz1%5
Midterm Examination1%30
Final Examination1%60
Workload Calculation
ActivitiesCountPreparationTimeTotal Work Load (hours)
Lecture - Theory140228
Assignment51110
Reading140228
Individual Work140228
Quiz1112
Midterm Examination1112
Final Examination1112
TOTAL WORKLOAD (hours)100
Contribution of Learning Outcomes to Programme Outcomes
PÇ-1
PÇ-2
PÇ-3
PÇ-4
PÇ-5
PÇ-6
PÇ-7
PÇ-8
PÇ-9
PÇ-10
PÇ-11
OÇ-1
4
2
OÇ-2
3
4
OÇ-3
2
1
3
OÇ-4
2
3
OÇ-5
5
2
3
Adnan Menderes University - Information Package / Course Catalogue
2026