1.1 Flashcards
____ harbor one or more types of microorganisms
Food
MICROORGANISMS
Desirable role - 1. ______
Undesirable role - 2. _____, 3. ______
- Fermentation
- Spoilage, 3. Food borne dseases
- __________ reported that, using a microscope, he had seen minute living worms in putrid meat and milk.
In 1664, 2. ___________ described the structure of molds.
The first person to see different types of microorganisms, especially bacteria, under a microscope that probably did not have a magnification power above 300×, was 3. ________. He observed bacteria in saliva, rainwater, vinegar, and other materi- als; sketched the three morphological groups (spheroids or cocci, cylindrical rods or bacilli, and spiral or spirilla); and also described some as being motile. He called them animalcules, and between 1676 and 1683, he reported his observations to the newly formed leading scientific organization, The Royal Society of London, where his observations were read with fascination.
- Athanasius Kircher
- Robert Hooke
- Anton Van Leeuwenhoek
By 1838, 1._______ (who introduced the term bacteria) had proposed at least 16 species in four genera.
By 1875, 2._______ had developed the preliminary classification system of bacteria. He was also the first to discover that some bacteria produced spores.
The existence of 3.________ was recognized in the mid-19th century, they were observed only after the invention of the electron microscope in the 1940s.
- Ehrenberg
- Ferdinand Cohn
- submicroscopic viruses
1.______ - generation of some form of life from nonliving objects, had many powerful followers among the educated and elite classes. Since the time of the Greeks, the emergence of maggots from dead bodies and spoiled flesh was thought to be a result of this generation.
2. What Period? __________
- The theory of spontaneous generation
- Renaissance Period
1._______ disproved the theory about spontaneous generation by showing that the maggots in spoiled meat and fish could only appear if flies were allowed to contaminate them.
In 1749, 2._______ showed that boiled meat and meat broth, following storage in covered flasks, could have the presence of animalcules within a short time. This was used to prove the appearance of these animalcules by spontaneous generation.
3._______ showed that boiling the meat infusion in broth in a flask and sealing the flask immediately prevented the appearance of these microscopic organisms, thereby disproving Needham’s theory.
- Redi
- Turbevill Needham
- Lazzaro Spallanzani
1._________ showed the need of oxygen for life
2.______ (1830), by passing air through acid; 3._______ (1838), by passing air through red-hot tubes; and 4.______ (1854), by passing air through cotton showed that bacteria failed to appear in a boiled meat infusion even in the presence of air.
5.________ demonstrated that, in a boiled infusion, bacteria could grow only if the infusions were contaminated with bacteria carried by dust particles in the air.
- Antoine Laurent Lavoisier and his coworkers
- Schulze
- Theodore Schwann
- Schröeder
- Louis Pasteur
1.________, in 1875, showed that wine fermentation from grapes and the souring of wine was caused by microorganisms. He also proved that spoilage of meat and milk was associated with the growth of microorganisms. Later, he showed the associa- tion of microorganisms with several diseases in humans, cattle, and sheep, and he also developed vaccines against a few human and animal diseases caused by microorganisms, including rabies.
2.________, in Germany (in the 1880s and 1890s), isolated pure cultures of bacteria responsible for anthrax, cholera, and tuberculosis. He also developed the famous Koch’s postulates to associate a specific bacterium as a causative agent for a specific disease. Along with his associates, he also developed techniques of agar plating methods to isolate bacteria in pure cultures and to determine microbial numbers in a sample, the Petri dish (by Petri in his laboratory), staining methods for better microscopic observation of bacteria, and the use of steam to sterilize materials to grow bacteria.
- Pasteur
- Robert Koch
Microbiology was divided into several subdisciplines, such as…….(5)
medical microbiology
industrial microbiology
soil microbiology
plant pathology
food microbiology
Around _______ B.C., agriculture and animal husbandry were adopted by the early civilizations, a food supply, especially agri- cultural produce, became available in abundance during the growing seasons.
8000 B.C.
_______ B.C., many food preservation methods, such as drying, cooking, baking, smoking, salting, sugaring (with honey), low-temperature storage (in ice), storage without air (in pits), fermenta- tion (with fruits, grains, and milk), pickling, and spicing were used, probably mainly to reduce spoilage.
Between 8000 and 1000 B.C.
This method is used to produce various types of desirable foods from milk, meat, fish, eggs, grains, fruits, and vegetables. Not just to preserve food
Fermentation
Function of Food Microbiology
- Transmission of disease
- Fermentation of food
- Spoilage of food
In the _________, studies continued to understand the association and importance of microorganisms, especially pathogenic bacteria in food.
Early 20th century
• 1._______ in the 1870’s – major development in food microbiology
• Followed by many other scientist before the end of the 2.________ century
• Establishment of early food microbiology in the 3.________ century
- Pasteur
- Before the end of 19th century
- 20th century
FOOD FERMENTATION
1822 C.J. Person named the microscopic organism found on the surface of wine during
vinegar production as 1.________.
Pasteur, in 1868, proved that this organism was associated with the conversion of alcohol to acetic acid and named it. 2.________. In 1898, Martinus Beijerinck renamed it 3._________.
1837 Theodor Schwann named the organism involved in sugar fermentation as 4._______(sugar fungus).
1838 Charles Cogniard-Latour suggested that growth of 5._______ was associated with alcohol fermentation.
1860 Louis Pasteur showed that fermentation of lactic acid and alcohol from sugar was the result of growth of specific bacteria and yeasts, respectively.
1883 Emil Christian Hansen used pure cultures of 5.________ to ferment beer.
- Mycoderma mesentericum
- Mycoderma aceti
- Acetobacter aceti
- Saccha romyces
- yeasts
FOOD SPOILAGE
1804 1.__________ developed methods to preserve foods in sealed glass bottles
by heat in boiling water. He credited this process to Lazzaro Spallanzani (1765), who
first used the method to disprove the spontaneous generation theory.
1819 2.________ developed canning preservation of foods in steel cans. 3._________
introduced tin lining of metal cans in 1839.
1870 4.________ recommended heating of wine at 145°F (62.7°C) for 30 minutes to destroy
souring bacteria. F. Soxhlet advanced boiling of milk for 35 minutes to kill contami- nated bacteria. Later, this method was modified and named 5._______ and used to kill mainly vegetative pathogens and many spoilage bacteria.
1895 6._______ showed that gaseous swelling with bad odors in canned peas was a result of the growth of heat-resistant bacteria (spores).
- Francois Nicolas Appert
- Peter Durand
- Charles Mitchell
- L. Pasteur
- pasteurization
- Harry Russell
FOOD BORNE DISEASE
1820 1.________ described food poisoning from eating blood sausage (resulting from
botulism). Fatal disease from eating blood sausage was recognized as early as
a.d. 900.
1849 2._______ suggested the spread of cholera through drinking water contaminated
with sewage. In 1854, Filippo Facini named the cholera bacilli as 3._______,
which was isolated in pure form by Robert Koch in 1884.
1856 4._______ suggested that water contamination with feces from infected persons
spread typhoid fever and advocated the use of chlorine in the water supply to overcome the problem. In 1800, G. de Morveau and W. Cruikshank advocated the use of chlorine to sanitize potable water.
- Justin Kerner
- John Snow
- Vibrio cholerae
- William Budd
MICROBIOLOGY TECHNIQUES
1854 1.________ and 2.________ used cotton to close tubes and flasks to
prevent microbial contamination in heated culture broths.
1876 3.________ used methylene blue (a synthetic dye) to stain bacteria in aqueous suspensions.
1877 4._______ showed the heat resistance of Bacillus subtilis endospores.
1878 5.________ isolated Streptococcus (now Lactococcus) lactis in pure culture by serial
dilution from sour milk.
1880s 6._______ and his associates introduced many important methods that are used
in all branches of microbiology, such as solid media (first gelatin, then agar) to purify and enumerate bacteria, the Petri dish, flagellar staining, steam sterilization of media above 100°C, and photography of cells and spores.
1884 7._________ developed Gram staining of bacterial cells.
- Heinrich Schröder, 2. Theodore von Dusch
- Car Weigert
- Ferdinand Cohn
- Joseph Lister
- Robert Koch
- Hans Christian Gram
◾ Development of strains with desirable metabolic activities by genetic transfer among strains
◾ Developmentofbacteriophage-resistantlacticacidbacteria
◾ Metabolic engineering of strains for overproduction of desirable metabolites
◾ Development of methods to use lactic acid bacteria to deliver biologically relevant proteins
or vaccines
◾ Sequencing genomes of important lactic acid bacteria and bacteriophages for better understanding of their characteristics
◾ Food biopreservation with desirable bacteria and their antimicrobial metabolites
◾ Development of strains with desirable metabolic activities by genetic transfer among strains
◾ Developmentofbacteriophage-resistantlacticacidbacteria
◾ Metabolic engineering of strains for overproduction of desirable metabolites
◾ Development of methods to use lactic acid bacteria to deliver biologically relevant proteins
or vaccines
◾ Sequencing genomes of important lactic acid bacteria and bacteriophages for better understanding of their characteristics
◾ Food biopreservation with desirable bacteria and their antimicrobial metabolites
Food Fermentation/Probiotics
◾ Identification and control of new spoilage bacteria associated with the current changes in food processing and preservation methods
◾ Spoilageresultingfrombacterialenzymesoffrozenandrefrigeratedfoodswithextendedshelflife
◾ Development of molecular methods, including nanotechnology, to identify metabolites of
spoilage bacteria and predict the potential shelf life of foods
◾ Importance of environmental stress on the resistance of spoilage bacteria to antimicrobial
preservatives
◾ Microbial community, ecology, and quorum sensing in food
Food Spoilage
Classification of Microorganisms
Bacteria
Archaea
Eukarya
Nomenclature Examples
Saccharomyces cerevisiae
Penicillium roquefortii
Listeria monocytogenes
Lactobacillus acidophilus
Yeast —— Mold
1. Cell type
2. Cell structure
3. Cell characteristics
Yeast
1. Eukaryotic
2. Unicellular
3. Oval, spherical, or elongaed
Mold
1. Eukaryotic
2. Multicellular
3. Non motile, filamentous, and branced
Bacterial cell
1. Cell structure
3 morphological forms
2.
3.
4.
E.g.
5.
6.
- Unicellular
- Spherical (cocci)
- Rod shaped (bacilli)
- Curved (comma)
- Bacillus thuringiensis
- Klebsiella
Classification of bacteria according to respiration
- Obligate aerobes
- Obligate anaerobes
- Facultatively anaerobic bacteria
- Microaerophilic bacteria
- Aerotolerant baceria
- ______ - can grow with or without oxygen
- ______ - require oxygen to survive
- ______ - do not require oxygen but can tolerate its presene
- ______ - Bacteria that cannot propagate oxygen
- ______ - Require low levels of oxygen
- Facultatively anaerobic bacteria
- Obligate aerobes
- Aerotolerant bacteria
- Obligate anaerobes
- Microaerophilic bacteria
- _____ are regarded as noncellular entities or particles. The proteins forming the head (surrounding the nucleic acid) and tail are called capsids. A 2. _______ attaches itself to the surface of a host bacterial cell and inoculates its nucleic acid into the host cell.
Viruses implicated in food borne outbreaks:
3. ________ - small, naked, polyhedral enteric virus approximately 30 nm in diameter.
4. ________ - virus that causes vomitting
- Virus
- bacteriophage
- Hepatitis A
- Norovirus
