Micor Lab Quiz 6 (HO1, HO2, 24, 25)

Acidophilic

*Acid-tolerant microbes*

A health hazard associated with eating undercooked hamburger meat is infection or intoxication from: a. Staphylococcus aureus b. Listeria monocytogenes c. Helicobacter pylori d. Escherichia coli

E. coli

Lacto-fermentation

It's a microbial process that produces lactic acid at the end products.

The most common contaminant of poultry is bacteria of the genus: a. Staphylococcus b. Listeria c. Clostridia d. Salmonella

Salmonella

A common characteristic of bacterial pathogens found in the soil is: a. spirilla shape b. cocci shape c. spore formers d. Gram negatives

Spore formers

Virulent

Strain of form of microbe has characteristics that make it more dangerous (e.g., resistant to numerous antimicrobial drugs, produce toxins, etc.)

The difference between foodborne intoxication and infection is: a. presence of viable bacteria in the food b. types of symptoms experienced c. fever onset d. length of incubation period

presence of viable bacteria in the food

Wine Production

produced when the yeast Saccharomyces cerevisiae ferments grapes. S. cerevisiae naturally in grapes skin, but more are added to fermentation process to prevent contamination by undesired microbes. S. cerevisiae uses the sugars in the grapes to produce *Ethanol* (drinkin alc.) and *CO2* (gas) which gives varieties of flavors found in wine.

Avirulent

strain or form of a microbe that has few, if any, characteristics that make it dangerous (e.g., does not form toxins or have a protective capsule)

Which level of soil would contain the highest concentration of microbes? a. loam b. bedrock c. topsoil d. humus

topsoil

Bacteria In Dental Plaque

*BIOFILM* -a community that adheres to surface w/a sticky film produce by colonized bacteria. -streptococcus responsible for producing biofilm: *S. mutans + S. sanguinis* -young or immature plaque contains primarily of Gram-positive Streptococcus cells. -as plaque mature, a shift in bacterial population occurs. Gram-negative, long rod-shaped bacteria begin to grow in the biofilm and spirochetes. -this shift occurs at the same time w/a decay in dental health, especially w/the present of spirochetes.

Plaque

*Layer of dextran; using SUCROSE* (common table sugar) -S. mutans/S. sanguinis, THEY form dextran by breaking DOWN sucrose via this following reaction: *SUCROSE = GLUCOSE + FRUCTOSE*

Pasteurization

*Louis Pasteur* a microbiologist who found that heating the liquids just enough to kill most of the bacterias resolve the problem of competing microbes that *sour* food products into acetic acid, vinegar. -the process of heating food, followed by a quick cooling -reduce spoilage and kills potentially harmful pathogens.

Normal Microbiota

*Normal flora* -human lives w/an extraordinary number of microbes. -found *in and around* the human body w/out our notice. -can potentially cause disease when given the right opportunity. For example, there are million bacteria (Streptococcus) in each milliliter of saliva.

*S. mutans/S. sanguinis*

*S. mutans and S. sanguinis* are abundant in mouth and being the important contributor to dental caries. Both forming a sticky polysaccharide layer made of dextran (plaque) as substrate. Allows them to stick tightly to teeth.

Halophilic

*Salt tolerant microbes*

Lactic Acid Bacteria + The Fermentation of *Cabbage*

*Sauerkraut* Example: Japanese tsukemono, Korean kimchi, or Filipino atchara. -fermented cabbage product is produced by the microbial process called *Lacto-fermentation* which produce lactic acid at the end product. -Lactic acid is found naturally on cabbage leaves. -most commonly: *Lactobacillus + Leuconostoc* takes part in fermenting the sugars in cabbage/producing lactic acid.

The most common pathogens found in soil are:

*Spore-forming bacteria, Bacillus, and Clostridium* 1. *anthrax* (Bacillus species)- a fatal respiratory disease that infects cattle, but can transfer to human. 2. *tetanus* (spore of a Clostridium)- when introduced to a deep puncture wound, germinate to cause the disease. 3. *mycoses* (Pseudomonas aeruginosa) is a common infection in the hospital, and also in soil. also, *Blastomyces, Coccidioides, Aspergillus*, and *Histoplasma*: these organisms are associated w/a deep systemic respiratory disease, characterized as *PPI* (primary Pulmonary infection).

Lactic Acid Bacteria and The Fermentation of *Milk*

*Yogurt* the process responsible is *Lacto-fermentation* which ferment the lactose present in milk such as, cow, goat, sheep, camel and yak's milk. -to make yogurt remove undesired microbes prior to adding the inoculum. Hence, predominant desired lactic acid bacterias. -heating/treating the milk with heat: 80 Celsius (176 F) for 15 mins.

Lysozyme

*a chemical defense against bacteria* -lysozymes are barriers that are capable of degrading the peptidoglycan cell walls of bacteria. -found in many body secretions: tears, saliva, + mucus which prevent bacterial entry. -also found in chicken egg whites.

Kefir

*fermented milk product* Due to lactic acid found in the milk which suppressed the growth of harmful bacterias in the intestines at old age.

Probiotics

*live microorganisms thought to be beneficial for the overall health of the human host* -such as maintaining the digestive system, prevention of cancers, lowering cholesterol, BP, and improve immunity. -most COMMON probiotic *Lactobacillus, Bifidobacterium, and Acidophilus* -the popularity of probiotic is fairly recent, but the idea of probiotic date back since 1900's by *Ilya Metchnikoff*. In 1950's *probiotic* was established due to the rises of fermented foods. Metchnikoff hypothesized those that consume *Kefir* lives longer.

Fermentaion

*metabolism of organic substrates to produce organic waste products*. # of beneficial bacterias outnumbers the # of pathogenic bacterias. *WE humans* benefit from microbes and their products are in the food industry. -Common fermentation products: ethanol, drinking alc, lactic acid (to make yogurts/cheese). -The organisms responsible for these products include *yeasts* (ethanol/CO2 fermentation) and lactic acid bacteria (lactic acid fermentation).

The Effects of *Pasteurization* On Wine Fermentation

-to lower the # of potential pathogens to ensure the safety of the food product -to increase the shelf life of the food product by reducing the total number of viable microbes. -sterilization will destroy the quality and taste of the food product. Example of food pasteurization(s): 1. *High temperature/Short time* (HT/ST) pasteurization involve incubation at a temp of (161 F) for 15-20 seconds. 2. *Ultra-high temperature* (UHT) involves a temp of (275 F) for a fraction of a second.

At which dilution would you expect to find the lowest microbial numbers? a. 10 -1 b. 10 -2 c. 10 -3

10 -3

Sucrose and Dental Health

Another species of Streptococcus found in mouth: *S. salivarius*. -typically colonizing the surface of the tongue. -all 3 Streptococcus: S.mutans, s. sanguinis, and S.salivarius can be found in saliva. -can be distinguished based on the colony morphologies.

Based on a previous laboratory exercises and lecture material, which of te following would be expedcted to be recovered only from a deep soil sample? a. Bacillus bacteria b. Aspergillis fungi c. Clostridium bacteria d. Histoplasma fungi

Clostridium bacteria

Lactic Acid Bacteria

Various Streptococcus *Obligate FERMENTERS* -produce lactic acid as the waste product. -can always be found in the mouth; weakens teeth. -*lactic acid provides 2 purposes*: gives off sour flavors and lower pH level to inhibits microbial growth. -acidophilic -halophilic

which of the following is a pathogen normally found in soil? a. Clostridium tetani b. Clostridium perfringens c. Pseudomonas aeruginosa d. all of these

all of these

Which of the following is not found in soil? a. algae b. protists c. viruses d. all of these are found in soil

all of these are found in soil

The most common microbes found in soil are: a. yeasts b. algae c. bacteria d. molds

bacteria

Microbial Succession

change in the population of microbe over time during fermentation. heterogeneous (mixed species of microbes) yield to the homogenus population of just lactic acid bacteria as the pH lower.

a rapid way to distinguish between Escherichia coli and Salmonella in food is to a. determine lactose fermentation b. perform a Gram stain c. examine microscopic cellular morphology d. perform an oxidase test

determine lactose fermentation

Which of the following is least likely to harbor viable microbes when kept at room temperature? a. potato salad b. dried fruits c. uncooked sausages d. uncooked chicken

dried fruits

Which of the following soil microbe most often causes respiratory infections? a. fungi b. bacteria c. viruses

fungi

The nonliving component of soil is: a. humus b. pumice c. silicon d. laterite

humus