1. Introduction FOOD Microbiology MEDI 2371
Prof. Dr. Abdelraouf A. Elmanama Islamic University of Gaza , Palestine

2. Course evaluation
Midterm Exam =25
Final Exam = 60
Attendance = 5
Quizzes =10
Course description
Food products safety and security are issues of growing importance especially with growing number of foodborne illnesses related to raw and ready-to-eat food products. This course deals with basic concepts in food microbiology, factors affecting various types of foods, sources and growth of microbes in food, foodborne microorganisms and their relationship to the food supply and public safety. Factors, that influence microbial proliferation in foods, affect food spoilage, food preservation and disease are provided. Food borne illnesses outbreak investigation is also discussed. Quality systems used in food industries (HACCP) constitute an integral part of the course.

3. Intended Learning Outcomes
Upon the completion of this course, students will be expected to:
1) Develop knowledge of the microbiology of food systems, including the intrinsic and extrinsic factors, which govern microbial proliferation in foods,
2) Understand theory of the effects of microorganisms in foods, including food preservation, fermentation, spoilage and disease,
3) Obtain a working knowledge of the techniques used to identify, enumerate and determine the metabolic activities of food-borne bacteria,
4) Develop/improve critical thinking, problem solving, and communication skills.

4. Outline of course content
Introduction
Historical role of microbiology in food preservation and safety
Microbial classification and taxonomy
Sources of organisms of significance to foods
Survey of organisms of significance to foods
Sampling methodology
Microbial ecology of foods
Microbial food spoilage
Methods of Food Preservation
Food borne Illnesses
Sanitation and quality control programs
Trends in Food Microbiology
Rapid and molecular methods
Emerging pathogens and surveillance

5. Definition
Food Microbiology: is the study of microorganisms that inhabit, make or contaminate food.
Many microorganisms are used to make food e.g
Bacteria which converts liquid milk into yogurt or cheese,
Yeast for making bread, through fermentation.
Other microorganisms or the toxins they produce cause spoilage of food.

6. Foodborne diseases e.g gastroenteritis and salmonellosis results from eating contaminated food with various types of microorganisms.
Safety of food must be ensured to protect human health.
Food preservation is being used to avoid health hazards.
Preservation methods include
Drying,
Cooking,
Smoking,
Salting,
Sugaring,
Low temperature storage
Radiation.

7. Fermentation/Food production Foodborne diseases.
Following the discovery of microorganisms, scientists associated the role of these organisms with:
Food spoilage,
Fermentation/Food production
Foodborne diseases. F

8. FOOD Microbiology MEDI 2371
Historical Development of Food Microbiology
Prof. Dr. Abdelraouf A. Elmanama Islamic University of Gaza , Palestine

9. Historical Development of Food Microbiology
FOOD Fermentation
Louis Pasteur (1860) showed that fermentation of lactic acid and alcohol from sugar was the result of growth of specific bacteria and yeast.
He concluded that souring of milk was caused by the growth of organisms in it.
Theodor Schwan (1837) named the organism involved in sugar fermentation as Saccharomyces (sugar fungus).
Emil Chirstian hansen (1883) used pure culture of yeasts to ferment sugars.

10. FOOD Spoilage
Harry Russell (1895) showed that gaseous swelling with bad odors in canned peas was due to growth of heat-resistant bacteria (spores).
Tyndall(1876) observed that bacteria in decomposing substances were always traceable to air, substances or containers.
Bacillus coagulans was first isolated from coagulated milk by Hammer (1915).
In 1902 the term psychrophile was first used by Schmidt- Nielsen for organisms that grow at 0 oC.

11. Food Poisoning
In 1857 milk was incriminated as a transmitter of typhoid fever by W. Taylor In 1888 Gaertner first isolated Salmonella enteritidis from meat that had caused 57 cases of food poisoning. In 1894 T. Denys was the first to associate Staphylococci in food poisoning. In 1896 Van Ermengen first discovered Clostridium botulinum.

12. In 1906 Bacillus cereus food poisoning was recognized
In 1906 Bacillus cereus food poisoning was recognized. In 1937 paralytic shellfish poisoning was recognized. In 1939 gastroenteritis caused by Yersinia enterocolitica was first recognized by Schleifstein and Coleman In 1951 Vibrio parahaemolyticus was shown to be an agent of food poisoning. In 1960 the production of aflatoxin by Aspergillus flavus was first reported. In 1986 Bovine spongiform encephalopathy was first diagnosed in cattle in U.K.

13. Food Preservation
In 1810 preservation of food by canning was developed by Appert in France. Fish and Fruits were first canned in In 1842 H- Benjamin in U.K. introduced freezing foods by immersion in an ice and salt brine. In 1878 the first successful cargo of frozen meat went from Australia to England. In 1890 pasteurization of milk began in USA. In 1907, Metchnikoff isolated one of yogurt bacteria (Lactobacillus bulgaricus). In 1943, Procter in USA employed ionizing radiation to preserve hamburger meat.

14. Groups of Microorganisms In Food
FOOD Microbiology MEDI 2371
Groups of Microorganisms In Food
Prof. Dr. Abdelraouf A. Elmanama Islamic University of Gaza , Palestine

15. Groups of Microorganisms In Food
Viruses
Enteric Viruses
Hepatitis A and Hepatitis E Viruses
Rotavirus
Astrovirus
Enteric Adenovirus
Human Caliciviruses (Noroviruses and Sapporo Viruses)

16. Parasites Ascaris Trichinella Taenia Giardia Entamoeba Cyclospora
Toxoplasma

17. Molds Produce Mycotoxins Species of Aspergillus, Fusarium,
Penicillium,
Claviceps
Mycotoxins include:
Aflatoxin,
Ochratoxin,
Ergot Alkaloids

18. Bacteria Yersinia Vibrio Staphylococci Campylobacter Listeria
Salmonells
Shigella
Escherichia coli
Clostridia
Bacillus cereus

19. Important Bacterial Groups in Food
Bacteria have
A rapid growth rate.
Ability to grow under a wide range of conditions such as:
Temperature
Aerobiosis pH
Water activity
Utilization of food nutrients
They better survive adverse conditions such as survival of spores at high temperatures.

20. 1- Lactic Acid Bacteria
These bacteria produce large quantities of lactic acid from carbohydrates,
species from genera
Lactococcus
Leuconostoc
Pediococcus
Lactobacillus
Streptococcus thermophilus.

21. 3- Propionic Acid Bacteria
2- Acetic Acid Bacteria
They are bacteria that produce acetic acid , such as Acetobacter aceti
3- Propionic Acid Bacteria
They produce propionic acid and are used in dairy fermentation e.g Propionibacterium freudenreichii

22. 4- Butyric Acid Bacteria
They are the bacteria that produce butyric acid in relatively large amounts, Clostridium butyricum is included in this group.
5- Proteolytic Bacteria
Clostridium butyricum
They are bacteria that can hydrolyze proteins because they produce extracellular proteinases, they include species in the genera Micrococcus, Alteromonas,
Staphylococcus Flavobacterium
Bacillus Alcaligenes
Clostridium some Enterobacteriaceae
Pseudomonas Brevibacterium.

23. 7- Saccharolytic Bacteria
6- Lipolytic Bacteria
They hydrolyze triglycerides as they produce lipases. Species in genera
Micrococcus, Alteromonas
Staphylococcus Flavobacterium
Pseudomonas
7- Saccharolytic Bacteria
They hydrolyze complex carbohydrates, Species in the genera Bacillus Pseudomonas Clostridium Enterobacter.

24. 8- Thermophilic Bacteria
They are the bacteria that are able to grow at 50 oC and above. Species from genera Bacillus Streptococcus Clostridium Lactobacillus Pediococcus,
9- Psychrotrophic Bacteria
They are the bacteria that are able to grow at refrigerated temperature. Some species from
Pseudomonas Yersinia
Alteromonas Aeromonas
Listeria,

25. 10- Thermoduric Bacteria
They are the bacteria that are able to survive Pasteurization temperature treatment. Some species from Micrococcus, enterococcus, Lactobacillus, Bacillus(spores), and Clostridium (spores) are included in this group.
11- Halotolerant Bacteria
Bacteria that are able to survive high salt concentration. Some species from Bacillus, Stahylococcus, Vibrio are included in this group.

26. 12- Aciduric Bacteria 13- Osmophilic Bacteria
They are the bacteria that can survive low pH.
Some species from Lactobacillus, Lactococcus, Enterococcus, and Streptococcus are included in this group.
13- Osmophilic Bacteria
Bacteria that can grow at a relatively higher osmotic environment than that needed for other bacteria.
Some species from genera Staphylococci, Leuconostic, and Lactobacillus are included in this group.
They are much less osmotic than yeasts and molds.

27. 14- Gas producing Bacteria
They are bacteria that produce gas(CO2, H2, H2S) during metabolism of nutrients. Species from genera Leuconostic, Lactobacillus, Propionibacterium, Escherichia, Enterobacter, Clostridium and Desulfotomaculum are included in this group.
15- Slime- producing Bacteria
They are the bacteria that produce slime because they synthesize polysaccharides.
Examples include Xanthomonas, Leuconostic, Alcaligenes, Enterobacter and lactobacillus.

28. 15- Spore-Forming Bacteria
They are the bacteria that have the ability to produce spores.
Species from Bacillus, Clostridium, and Desulfotomaculum are included in this group. They are further divided into:
Aerobic sporeformers
Anaerobic sporeformers
Flat sour sporeformers
Thermophilic sporeformers
Sulfide-producing sporeformers

29. 17- Aerobic Bacteria 18- Anaerobic Bacteria
They are the bacteria that require oxygen for growth and multiplication. Examples include Pseudomonas, Bacillus, and Flavobacterium
18- Anaerobic Bacteria
They are the bacteria that cannot grow in the presence of oxygen.
Species from Clostridium are included in this group.

30. 19- Facultative anaerobic Bacteria
They are bacteria that are able to grow in both the presence and absence of oxygen. Lactobacillus, Pediococcus, Leuconostoc. Enteric pathogens, and some species of Bacillus, Serratia and Coliforms are included in this group.
20- Coliform Bacteria
Species from Escherichia, Enterobacter, Cirtbacter and Klebsiella are included in this group.
They are used as index of sanitation.

31. 20- Fecal Coliform Bacteria
Mainly Escherichia coli is included in this group. They are also used as an index of sanitation.
21- Enteric Pathogenic Bacteria
Pathogenic Salmonella, Shigella, Campylobacter, Yersinia, Escherichia, Vibrio, Listeria, and others that can cause gastrointestinal infection are included in this group

32. Descriptive Terms
Indicator organism (s) An indicator organism or group of organisms is one whose numbers in a product reflect the success or failure of (good manufacturing practices). GMP Coliform group of microorganisms and Escherichia coli are commonly used as indicator organisms.

33. Index organism
An index organism is one whose presence implies the possible occurrence of a similar but pathogenic organism.
E. coli is used as an index organism and its presence indicates possible presence of pathogenic enterobacteriacea e.g Salmonella sp.

34. Food borne diseases
1- Those which cause the disease by infection (food infection) 2- Those which produce toxin in food (food poisoning or intoxication) Those which cause infection cause infection when consumed together with food. Common organisms in this category include Salmonella typhimurium, Vibrio parahaemolyticus enteropathogenic E. coli, Yersinia enterocolitica

35. Toxin-Producing Organisms
These are microorganisms which cause intoxication, they must grow in food in large numbers and produce enough toxin and when consumed together with food cause intoxication.
Common microorganisms in this category include
Clostridium botulinum,
Staphylococcus aureus
Toxigenic fungi e.g. Aspergillus flavus.

36. Infectious Microorganisms
These are the organisms whose presence in small numbers in food or water and when consumed can cause infection.
In this case the food acts as a vector but not necessarily as a growth medium.
Infectious organisms can be transmitted by various ways including man to man and are said to be contagious.
Organisms in this group include;
Vibrio cholerae O1,
Salmonella typhi,
Shigella sonnei,
Hepatitis A …etc.

37. Spoilage Organisms
Spoilage organisms are the organisms whose growth in the food causes undesirable characteristics in that food.
Any organism which is not intentionally added into food is considered a contaminant.
Growth of the contaminant in that food will spoil the food making it unfit for human consumption.
Some useful microorganisms e.g. Lactic acid bacteria are considered as spoilage organisms when in alcohol but not in milk.

38. End of Lecture Thank you
Please review presentation and summarize important points