• ADNAN MENDERES UNIVERSITY

  Department of Food Engineering

• FE 206 Food Microbiology I

• Lecture #1

• Cisem Bulut Albayrak, Ph.D.

• FE 206 Food Microbiology I

• Section I

• Tuesdays

• Lecture 08:30-10:15

• Lab 10:30-12:15

• Textbook

• Doyle and Buchanan, Food Microbiology: Fundamentals and Frontiers, 2013, 4th ed. ASM Press, ISBN: 978-1555816261

• Available in University Library as e-book

• Grading

• Attendance

• Student attendance is mandatory and students must attend all sessions

• Small tolerance may be shown

• At least 70 % attendance in lectures and

  80% in labs are expected

• Binomial nomenclature

• Saccharomyces cerevisiae

• Escherichia coli

• Homo sapiens

• Types of Microorganisms in Food

• Important Microorganisms in Foods

–Fungi

–Bacteria

–Parasites

–Viruses

–Algae

–Prions

• Fungus – Fungi

• Chytridiomycetes-Members are found in soil, fresh water, and saline estuaries.

• Zygomycetes- fungi that reproduce sexually by forming zygospores

• Ascomycetes

• Basidiomycetes

• Deuteromycetes (Fungi Imperfecti): No known sexual growth

• Fungus physiology and structure

• Most fungi are multicellular, forming a network of hyphae (sing. hypha)

• Hyphae that extend above the surface can produce asexual spores called conidia (sing. conidium)

–Conidia are often pigmented and resistant to drying

• Hyphae form compact tufts called mycelia

• Most fungal cell walls are made of chitin

• Fungal Diseases

• Fungi can cause disease (mycosis) in plants and animals

–Mycoses in humans range in severity from “athlete’s foot”     to       histoplasmosis

• Fungal Reproduction and Phylogeny

• Asexual reproduction in three forms

–Growth and spread of hyphal filaments

–Asexual production of spores

–Simple cell division (budding yeasts)

• Some fungi produce spores as a result of sexual reproduction

–Sexual spores can originate from the fusion of two haploid cells to form a diploid cell (ascospores, basidiospores, zygospores)

–Spores are resistant to drying, heating, freezing, and chemicals

• Ascomycetes

• Key genera: Saccharomyces, Aspergillus, Penicillium, Microsporum, Morchella

• Around 50,000 species of molds, yeasts, an plant parasites

• Also known as (aka) Sac fungi

• Budding Yeast

• Basidiomycetes

• Key genera: Agaricus, Amanita

• Over 30,000 described species

• Many are recognizable as mushrooms and toadstools

–Also yeasts and pathogens of plants and humans

• Undergo both vegetative and sexual reproduction

• Zygomycetes

• Key genera: Rhizopus, Mucor, Encephalitozoon

–Known primarily for food spoilage

–Commonly found in soil and decaying plant material

–All are coenocytic (multi nuclei)

–Sexual spores are called zygospores

• Rhizopus stolonifer (black bread mold) is representative

• Microsporidia: unicellular, obligate parasites

–Often infect immune-compromised individuals

• Important Bacterial Groups

• Lactic acid bacteria (LAB)

–Gram (+), non-sporulating rods/cocci, produce lactic acid

–Lactobacillus, Lactococcus

• Acetic acid bacteria

–Gram (-), obligate aerobic, chemoorganotrophic

–Acetobacter

• Butyric acid bacteria

–Spore forming anaerobes

–Clostridium butyricum

• Important Bacterial Groups

• Proteolytic bacteria

• Lipolytic bacteria

• Thermophilic bacteria

• Psychrophilic bacteria

• Halophilic bacteria

• Sporeformers

• Sources of Microorganisms in Foods

• Water

–Water used in production

–Washwater

• Plants and Plant Products

–Human pathogens from contaminated soil, water

–Mold from soil

• Sources of Microorganisms in Foods

• Food Utensils and Packaging Materials

–Open served foods

• Intestinal Tract of the Human and Animals

–Pathogens

–E. coli, Salmonella

–Candida

–Enteroviruses

• Sources of Microorganisms in Foods

• Food Handlers

–Personal hygiene

• Food Ingredients

–Chemicals

–Spores

• Sewage!!!

• Sources of Microorganisms in Foods

• Animals, Birds, and Fish

–Natural flora of animals

• Air, Dust, and Soil

–Bacterial spores

–Fungus spores

• Miscellaneous Sources

• Animal feeds, Rodents, Insects

• Primary Sources of Microorganisms

• Pathogenic Escherichia coli – intestine

• Salmonella – intestine, poultry, eggs

• Campylobacter jejuni – poultry

• Staphylococcus aureus – nasal cavity

• Streptococcus pyogenes – nasal cavity

• Listeria monocytogenes – cheese, milk, fish

• Bacillus cereus – starchy foods, rice, pasta

• Brucella – raw milk and products

• Clostridium perfringens – soil

• Resources

• Brock Biology of Microorganisms, Pearson