Food Microbiology: History of Food Micro
How much atmospheric pressure is needed to sterilize a can of food? How much temperature is that?
1 atmospheric pressure. 121 Celsius (or 250 Fahenheit)
Who is the man who is accredited with first discovering the microbial world through a microscope?
1683 - Anton van Leeuwenhoek from the Netherlands examined & described bacteria thru a microscope. The Royal Society published scientific work, & invited Leeuwenhoek to communicate his microscopic observations.
What vaccines did Pasteur invent?
A vaccine used to protect sheep from anthrax by using Bacillus anthracis. A vaccine used to immune chickens from cholera using Pasteurella septica The rabies vaccine (most famous vaccine)
What are the only two bacterial genera that produce endospores?
Aerobic bacillus Clostridium anaerobic bacillus
What is the significance of drinking alcoholic beverages in an underdeveloped country?
Alcoholic beverages like beer and wine are much safer to consume than the local water supply, because the water is often contaminated with intestinal microorganisms that caused cholera, dysentery and other serious diseases. This was done in early civilizations too
Who attempted to disprove the Theory of Spontaneous Generation in 1765?
An Italian named Spallanzani tried by demonstrating that beef broth which was boiled and then sealed remained sterile.
When did government start to enact legislation to protect the quality of food?
Around the 1800s.
Government protects the public's food safety, yet still outbreaks occur despite efforts to develop the cleanest food supply in the world. Why?
As microbes are eliminated from food we create an environment free of competition which may allow opportunities for other microorganisms to grow & cause disease.
Who was "Typhoid Mary"? What happened to her?
Asymptomatic typhoid carrier who cooked for families. Over 10 years, 7 outbreaks of typhoid fever were traced back to her. She was arrested by authorities who wanted to remove her gall bladder but was released with her promise she would never cook for anyone again. She was reinstated after another outbreak was traced back to her & she stayed there until her death!
How is canning food a sterilization method?
Because of the pressure done to the food. Canning food is much like an autoclave in the lab.
How did Pasteur make the vaccine for anthrax?
By isolating an attenuated (avirulent) strain of the causative bacterium, Bacillus anthracis. Pasteur isolated the attenuated organisms by growing them at elevated temperature, 42 Celsius. Sheep exposed to the attenuated bacterium became immune to virulent strains.
What are the symptoms of a cholera infection?
Copious amounts of diarrhea! About 3 gallons of poop a day.
In 3000 BCE, what were the Egyptians doing with food?
Egyptians manufactured cheese & butter via fermentation. Again, fermented foods such as cheese and sour milk (yogurt) were safer to eat and resisted spoilage better than their raw agricultural counterparts.
Before Louis Pasteur, how was the process of fermentation thought of? How did Pasteur change that idea?
Fermentation was previously thought to be strictly a CHEMICAL process in the food. Pasteur proved fermentation is actually a BIOLOGICAL process done BY microorganisms in the food.
How did Schwann attempt to disprove Spontaneous Generation?
He also took a broth of nutrients and sterilized it by boiling, then heated the air above it to a high temperature. The result was that no microbes grew and no biological or chemical activity were observed in the broth either.
What did Louis Pasteur discover about the mechanism of fermentation?
He demonstrated that fermentation was a product of microbial activity & that different types of fermentation i.e. lactic, butyric, etc. were caused by different types of microorganisms.
What was John Needham's position on Spontaneous Generation?
He supported the idea of Spontaneous Generation.
How could microbes actually help prevent spoilage?
Identifying safe bacteria i.e. lactic acid bacteria which, when deliberately added to food, would inhibit growth of pathogens, but would not rapidly spoil the product themselves, though some lost shelf life seems inevitable. This could theoretically eliminate opportunistic infections.
Who caused the first step to disproving the Theory of Spontaneous Generation? How did they do it?
In 1665 an Italian physician by the name of Francesco Redi demonstrated that maggots on putrefying meat did not arise spontaneously but were instead the larval stages of flies by putting meat in container capped with fine gauze so that flies couldn't get access to deposit eggs.
What significant thing happened in 6000 BCE in reference to food microbiology?
In 6000 BCE, the earliest known recorded account of food spoilage.
Who demonstrated that air doesn't have to be heated to remain sterile using his famous swan-necked flasks that finally disproved spontaneous generation.
Louis Pasteur!
Who discovered milk was being spoiled by microbes?
Louis Pasteur!
Who is known as the father of food microbiology & microbiological science?
Louis Pasteur! He was the FIRST person to really appreciate and understand the CAUSAL relationship between microorganisms in infusions and the chemical changes that took place in those infusions.
What saved the French wine industry?
Louis Pasteur's discovery of micoorganisms as the cause of fermentation. By using this knowledge, he "pasteurized" wine.
How did the swan-necked flask work? How did it disprove Spontaneous Generation?
Microbes would get stuck in the bottom of the "neck" part of the flask.
Around the 1920s, there were also many outbreaks from spoilage of milk. What 4 types of outbreaks did the milk commonly cause?
Milk-borne typhoid fever Diphtheria Tuberculosis Brucellosis.
Although these early civilizations started to learn how to preserve foods, did they understand what was causing the fermentation?
No! They did not understand how these practices of preservation inhibited food spoilage or food borne disease. Their ignorance was compounded by a belief that living things formed spontaneously from nonliving matter, Theory of Spontaneous Generation.
Is boiling a method of sterilization or preservation? Why or why not?
No! Boiling water is not considered a sterilizing agent because the destruction of bacterial endospores and the inactivation of viruses cannot always be assured.
Has the United States always had the public interest in mind when it comes to food spoilage prevention?
No! In the U.S. many food industries hesitated to adopt industry-wide microbiological standards until they were economically threatened by the publicity which surrounded outbreaks of food borne disease.
Since 1925, the heat treatment for canned food is still practiced today. How many outbreaks of botulism has there been since?
Only 5-6 known incidents of botulism. Most of these incidents involved faulty containers, not under processing.
What type of vaccine did Pasteur use for chickens?
Pasteur developed the method to make chickens immune to cholera by using an attenuated bacterium that he had isolated in his laboratory.
What part of the method of creating the vaccine for sheep did Pasteur not understand?
Pasteur did not understand the basis for attenuation, we now know that virulence in this bacterium depends on the presence of a plasmid that cannot replicate at 42 Celsius.
How did Pasteur help modern medicine's sterilization techniques? And which doctor helped that happen?
Pasteur's argument that microbes cause disease eventually reached an English surgeon named Joseph Lister who used them to develop the first aseptic surgical procedures.
What did the Roman's in 1000 BCE start to do with their food to preserve it?
Romans used snow to preserve shrimp (low temp), records of smoked and fermented meats also appear.
In 3000 BCE, what preservative did several cultures start using for their food?
Several cultures learned to use SALT to preserve meat and other foods around this time.
What finally prompted the U.S. to develop a conservative heat treatment for canned foods? What was this process called?
Several outbreaks of botulism in the early 1920s. This heat treatment for canned foods is known as the 12D process. It reduces the probability of survival of the most heat resistant C. botulinum spores to one in a trillion (10^12 spores/gram)
In 7000 BCE, the Babylonians manufactured _______ what?
The Babylonians manufactured beer via fermentation.
Where did the first example of preserving food by "canning" occur? Who started it?
The French government offered 12,000 francs to anyone who could develop a practical way to preserve food. A French confectioner named Nicholas Appert was issued the patent after showing that meat could be preserved when it was placed in glass bottles and boiled.
Because Pasteur discovered the mechanism behind fermentation, it led him to conclude what theory about microbes?
The knowledge that microbes were responsible for fermentation and putrefaction led Pasteur to argue that microbes were also causative agents in disease.
What is Pasteurization? How was it first used?
The process of heating & denaturing microbes found in foods like milk. First used to destroy undesirable microbes in beer & wine.
Which toxin was responsible for many nasty outbreaks in the 1920s?
The toxin clostridium botulinum from poorly prepared canned foods. Clostridium botulinum is a Gram-positive, rod-shaped, anaerobic, spore-forming, motile bacterium with the ability to produce the neurotoxin botulinum.
Why did supporters of the Theory of Spontaneous Generation discount Spallanzani's experiment?
They discounted his work because they believed his treatment excluded O2 by having a sealed beef broth, which they thought was vital to spontaneous generation
What is the microbiological reason Napoleon's ambition to have a greater kingdom than Alexander the Great was thwarted?
While Napoleon was trying to conquer Russia, he went through Poland where epidemic typhus from lice killed most of his men with disease.
Did the U.S. Dairy Industry do anything about the outbreaks of milk-bourne illnesses?
Yes! It implemented microbiological control over milk via animal health, sanitation, pasteurization, & refrigeration, with all of these steps reinforced by bacterial standards. As a result, pasteurized milk was one of our safest foods by the mid-1900s.
When did wine first appear in history?
~3500 BCE
