What did John Tyndall discover about certain bacteria?
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Some bacteria can form resistant structures known as spores.
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What did John Tyndall discover about certain bacteria?
Some bacteria can form resistant structures known as spores.
What are some challenges associated with cultural techniques in microbiology?
They can be labor-intensive, have high recurrent costs, and long incubation times before results are obtained.
What is the hurdle concept in food preservation?
Adjusting multiple factors less severely to achieve an overall antimicrobial effect.
What did Francesco Redi's experiment involve?
Placing meat in dishes, some covered with gauze, to observe maggot development.
What are the three interrelated activities of Microbiological Risk Analysis (MRA)?
Risk assessment, risk communication, and risk management.
What was the first evidence of beer manufacture traced to?
Ancient Babylon in 7000 BC.
How do food preservation techniques affect microorganisms?
They manipulate intrinsic and extrinsic factors to slow or stop microbial growth and inactivate microorganisms.
Who conducted the earliest experiment to disprove spontaneous generation?
Francesco Redi in 1668.
What did Anthonie van Leeuwenhoek observe under the microscope?
Different types of animalcules, including cocci, bacilli, and spiral forms.
What technique did Pasteur develop to prevent contamination of microorganisms?
Aseptic techniques.
What is the role of selective and differential media in microbiology?
They favor the growth of a particular target microorganism and allow for clear distinction from other microflora.
What are some subdisciplines of microbiology?
Medical microbiology, mycology, soil microbiology, plant pathology, and food microbiology.
What discovery did Alexander Fleming make in 1928?
Some microorganisms produce natural compounds that inhibit the growth of competitors.
What should MRA contribute to?
Food safety objectives.
What are the primary causes of foodborne diseases?
Pathogenic bacteria, toxigenic molds, enteric viruses, and protozoa.
What process did Pasteur discover regarding yeast and bacteria?
Yeast ferments sugars to alcohol, and bacteria oxidize alcohol to acetic acid.
What does microbial physiology study?
Cell structure, growth factors, metabolism, and genetic composition of microorganisms.
What significant evolutionary event occurred about 1.2 billion years ago?
The evolution of sexual reproduction.
What are some examples of fermented foods?
Cheeses, yogurt, wine, beer, pickles, sauerkraut, and sausages.
What did John Turberville Needham conclude from his experiments with boiled broth?
He concluded that spontaneous generation occurred from nonliving matter.
What elements are involved in ISO 22000?
Interactive communication, system management, prerequisite programs, and HACCP.
What does the term 'probiotic' mean?
'For life'; refers to live microbial cell preparations that survive in the colon.
What are the oldest known fossils?
Prokaryotic cells, approximately 3.5 billion years old.
What does hazard characterization involve?
A qualitative/quantitative evaluation of the adverse effects of a risk, including the relationship between pathogen dose and effect.
What are the main causes of biological spoilage?
Inherent enzymes, growth of microorganisms, insect invasion, and contamination with parasites.
What are lactic acid bacteria (LAB) used for?
To produce fermented foods from animal and plant sources.
When did barley flourish in the Nile?
Around 18,000 BC.
What are Koch's postulates?
Criteria to identify the causative agent of disease.
What is biopreservation?
Extending storage life and enhancing safety of foods using natural microflora, starter cultures, and antimicrobials.
Which type of foods are more associated with foodborne diseases?
Foods of animal origin.
What preservation method did Francois Nicholoas Appert develop?
Canning, by preserving foods in sealed glass bottles using heat.
What are the four stages of microbiological risk assessment?
Hazard identification, hazard characterization, exposure assessment, and risk characterization.
What is food spoilage?
The unfitness of food for human consumption.
What percentage of the world's food supply is lost due to microorganisms?
About one-fourth.
What was proposed in the 1980s regarding the 'tree of life'?
The three domain system: Bacteria, Archae, and Eukaryote.
What factors can be studied to predict the growth and inactivation of microorganisms in food?
pH, a_w, temperature, preservatives, and other factors.
What benefits do fermented foods provide?
Increased shelf stability, aroma, flavor characteristics, and sometimes enhanced vitamin content and digestibility.
What are the economic impacts of foodborne diseases?
They can be fatal and cause large economic losses.
How old is the Earth?
About 4.6 billion years old.
Who was the first scientist to use a lens to study microorganisms?
Galileo Galilei.
What is the role of total quality management in food safety?
To control microorganisms, prevent microbial growth, and protect foods against contamination.
What was the only form of life on Earth for approximately 2 billion years?
Prokaryotic cells.
What is the cell theory proposed by Schleiden, Schwann, and Virchow?
All living things are composed of cells and all cells arise from other cells.
What methods were developed in the early twentieth century to handle microorganisms in foods?
Sanitation methods to reduce contamination and specific methods for isolation and identification.
What was the primary food source for nomadic populations during the last ice age?
Crops alongside wild animals.
What food preservation methods were developed between 8000 and 1000 BC?
Drying, cooking, baking, smoking, salting, sugaring, low-temperature storage, fermentation, pickling, and spicing.
What is the purpose of ISO 22000?
To specify requirements for a food safety management system that helps organizations identify and control food safety hazards.
How do beneficial microorganisms contribute to fermented foods?
They can reduce pH and produce antimicrobial agents like H2O2, organic acids, and bacteriocins.
What factors have increased the chances of foodborne disease outbreaks?
Mass production of foods, new processing technologies, storage changes, and increased food imports.
What did Louis Pasteur demonstrate with his S-shaped flask experiment?
He proved that bacteria could only grow in nutrient solutions that were contaminated by dust particles in the air.
What is HACCP?
Hazard Analysis and Critical Control Points, a system used in food production, processing, and preservation.
What knowledge should an individual gain from food microbiology courses?
Determination of microbiological quality of foods and sources of microorganisms contaminating foods.
What is the application of food safety principles in food production?
To ensure the safety and quality of food products.
What is pasteurization?
Heating food, such as wine, to destroy undesirable microorganisms.
What are some areas where the importance of microorganisms has been recognized?
Human and animal diseases, soil fertility, plant diseases, fermentation, food spoilages, and foodborne diseases.
What is risk characterization in food safety?
It is a qualitative/quantitative estimation of the probability and consequences of illness caused by a hazard.
What is the process for enumerating microorganisms in food?
Diluting a food sample in an inert liquid, inoculating onto a medium, and incubating.
Who constructed the first microscope and in what year?
Anthonie van Leeuwenhoek in 1676.
What new challenges does food microbiology address?
Problems introduced by new technologies in food production, processing, distribution, storage, and consumption.
What concept did Theodor Schwann extend to animals and vegetables?
That tissues originate from cells.
What did Jacob and Wollman discover in 1956?
The circular structure of the bacterial chromosome.
What is microbiology?
The branch of biological science that deals with microorganisms and agents that are invisible to the naked eye.
What can cause foodborne diseases?
Consumption of water and foods containing pathogenic microorganisms or their toxins in sufficient quantity.
Why is it important to isolate microorganisms in pure culture?
To study their morphological, physiological, biochemical, and genetic characteristics.
What antibiotic was purified by Howard Florey and Ernst Chain?
Penicillin G.
Which genera are commonly associated with probiotic microorganisms?
Lactobacillus and Bifidobacterium.
What type of cells evolved about 3 billion years ago?
Photosynthetic microorganisms known as cyanobacteria.
What is exposure assessment in microbiological risk assessment?
An estimation of the particular hazard based on food consumption patterns and incidence of the hazard.
What role do microorganisms play in food bioprocessing?
They can be used to produce fermented foods.
When did complicated eukaryotic cells (fungi) first appear?
Between 1.5 and 2.1 billion years ago.
What is 'tyndallization'?
A technique involving boiling and cooling to inactivate bacterial spores.
What theory was widely accepted from the Renaissance until the late nineteenth century regarding the origin of life?
Spontaneous generation.
What was Lazzaro Spallanzani's contribution to disproving spontaneous generation?
He showed that sealed flasks without air did not develop life, proving air was a source of contamination.
What is the significance of Good Manufacturing Practices (GMP) in food production?
GMP provides a framework for hygienic production of food, focusing on prevention rather than problem identification.
What is the significance of modifying intrinsic or extrinsic factors in food preservation?
It can achieve preservation but may dramatically change the product's qualities.
What shapes of bacteria did van Leeuwenhoek draw?
Rods, cocci, and spirals.
What is one goal of research in food microbiology?
To develop methods for rapid and effective detection of spoilage and pathogenic microorganisms.
What significant discovery did Watson and Crick make in 1953?
The structure of the DNA molecule.
What can cause foodborne illnesses?
Pathogenic microorganisms contaminating foods during handling, production, storage, serving, and consumption.
What did Sergei N. Winogradsky and Martinus W. Beijerinck contribute to microbiology?
They prepared the enrichment culture technique.
What happens to the shelf life of food when microbial growth is slowed?
The shelf life is extended, and different microorganisms may predominate.
When did the first living simplest cells evolve?
Between 3.8 and 3.5 billion years ago.
What is the focus of food microbiology?
The relationship of habitat, food preservation, occurrence of microorganisms in foods, and foodborne diseases.
What is involved in the identification of microorganisms in food?
Isolating individual colonies from mixed populations.
What classification system did Ferdinand Cohn develop?
A preliminary classification system of bacteria, discovering that some bacteria produced spores.
What advancements in microbiology occurred in the 1970s?
Development of recombinant DNA technology and genetic engineering.
What does the maximum frequency of occurrence of a hazard in food represent?
It is considered acceptable for consumer protection.
Name two pathogenic bacteria responsible for foodborne diseases.
Escherichia coli and Salmonella.
What did Theodor Schwann prove about yeast cells?
He proved that yeast cells were responsible for the conversion of sugars to alcohol, known as alcoholic fermentation.
What areas did Louis Pasteur study that contributed to food microbiology?
Milk souring, causes of diseases, and defects in wine.
What is the role of low pH, ethanol content, and dissolved CO2 in beer preservation?
They combine to restrict the range of microorganisms that can grow.
What did Matthias Schleiden propose in 1838?
That all plants are composed of cells.
What is one method to control spoilage and pathogenic microorganisms?
Designing correct procedures in food processing areas.
What areas of food microbiology have expanded since the 1950s?
Food fermentation/probiotics, food spoilage, foodborne diseases, and food safety.
What did John Tyndall show regarding boiled infusions?
He showed that boiled infusions could be stored in dust-free air without microbial growth.
How can mathematical models assist in food safety?
They can determine the influence of various parameters on microorganisms, providing rapid first-hand information.
How can new technologies be adapted in food processing?
By identifying how they can be effectively used.