The term potable water refers to water that is
A. safe to swim in but not drink.
B. safe to drink.
C. only good for irrigation.
D. contaminated with chemicals.
An effective means used early in the 19th century to clear water of the majority of bacteria was the use of
A. chlorine.
B. iodine.
C. alcohol.
D. sand filters
Why might a large number of competing microorganisms in a food sample result in lack of sensitivity of culture methods for detecting pathogens?
A. Many microbes secrete compounds that can be toxic for their competitors. If you need a pathogenic microbe to grow in a culture in order to detect it, these toxic compounds might inhibit the growth of the pathogen and impede the test.
B. You can't obtain a pure culture from a food sample that has a large number of microbes present. It would be impossible to detect only one from within the sample.
C. Culture methods often rely on biochemical changes taking place in medium for identification. With multiple microbes present, you may not be sure that the biochemical change observed is from the presence of a pathogen or from some other non-dangerous bacterium that also induces the biochemical change.
D. The sheer number of microbes present might shut down the growth/replication of a pathogenic microbe in a food sample due to a 'starving out' effect. If it can't grow/replicate, it won't be detectable by a culturing method test.
E. Many microbes secrete compounds that can be toxic for their competitors. If you need a pathogenic microbe to grow in a culture in order to detect it, these toxic compounds might inhibit the growth of the pathogen and impede the test AND culture methods often rely on biochemical changes taking place in medium for identification. With multiple microbes present, you may not be sure that the biochemical change observed is from the presence of a pathogen or from some other non-dangerous bacterium that also induces the biochemical change.
High concentrations of nucleic acids in the diet may lead to high levels of uric acid in the blood.
Indicate whether this statement is TRUE or FALSE.
Why would the use of a known, reliable starter culture improve the safety of fermented meat products?
A. It doesn't. All fermented meat products are inherently unsafe since we can't determine what fermentation products are left behind in the food. Some of them may be toxic.
B. By using pure starter cultures, we KNOW what we're adding in, and how much. We can control the microbial fermentation precisely to best prepare the food product.
C. We need to be very careful which microbes are introduced into a food product. Some microbes can interact with microbes already present in the food, producing toxins and toxic byproducts that might harm human beings.
D. Not every fermenting microbe ferments the same way. Even different strains of the same species might produce different products. Some of these products might not be safe for human consumption.
E. By using pure starter cultures, we KNOW what we're adding in, and how much. We can control the microbial fermentation precisely to best prepare the food product AND not every fermenting microbe ferments the same way. Even different strains of the same species might produce different products. Some of these products might not be safe for human consumption.
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