What orginism did we use in the production of wine?
What substances are produced as a result of saccharomyces cerevesiae fermenting sucrose?
What was the purpose of the balloon?
attached over the lip of the flask to exclude o2 uptake and trap gases (Co2 which is an acid) that might be produced
What effect did the fermentation have on the pH of the wine? Why is that?
Fermentation will make the juice more acidic due to the acids added during the fermentation process. However our pH remained the same.
What two orginisms are typically used to produce yogurt?
Streptococcus thermophilus and lactobacillus bulgaricus
What products of fermentation is responsible for converting milk into yogurt?
Lactobacilli which are products of fermentation
What changes did you note after the milk was allowed to ferment?
Milky aroma--sour-milk aroma
Why cool the milk to 45*C before adding the starter culture?
because any degree higher would kill the micorbes or inhibit their growth. 45* is the optimal temp.
Destroy or inhibit the growth of other microbes. They are synthesized, secreted by certain bacteria, actinomycetes and fungi.
drugs created in the lab, where the mode of action, possible adverse effects in the host and the scope of its anti-microbe behavior is known
a standardized diffusion procedure (using confetti like filter paper discs) used to determine the drug susceptibility of microbes isolated from infectious processes?
the clear zone surrounding each disc that indicated the presence of growth inhibition
Zone of inhibition
referes to enhanced bactericidal activity. when the sum of the effects of 2 or more chemotherapeutic agents combined is greater than their effects when used alone?
prevents transpeptidation, produces a weakended peptidogylcan structure
prevents H+ bonding b/w the anticodon and t-RNA amnio acid complex and the codon on the mRNA during protein synthesis?
inhibits RNA synthesis
misreading of codons in mRNA, interfers with protein synthesis
prevents peptide bond formation b/w amino acids during protein sythesis
inhibits cell wall sythesis
destruction of cell membrane
inhibits DNA sythesis
What organisms were more resitant to antibiotics overall?
Which organisms were more sensitive to abx overall?
Which antibiotics worked against the most type of bacteria?
Whcich abx were least effective?
Which types of organisms are more resistant to abx in general?
Germicidal denaturing of proteins, disrupts cell membrane
phenol like, poisoniou-external use only, known as lysol
lipid solvent, denaturing and coagulation of proteins, wetting agent in tincutures
reacts with water to form hypochlorus acids which is bactericidal, germicide from combination with proteins, noncompetitive inhibition of enzymes
mercuric ion results in precpitation of cellular proteins, noncompetitive inhibition of specific enzymes caused by sulfhydryl group SH
precipitate cellular proteins, interfere with metabolic activity, inorganic salt are germicidal
lowers surface tension and aids in mechanical removeal of bacteria and soil, interfers or depresses the metabolic activities of microbes, disrupts cell membrane, alters cell permeability
Surface active agents
alkylating agent causes reduction of enzymes
What is the diffeence in anticeptics and disinfectants?
what they target, anticeptics are used on living tissue, disinfectants are used on objects
Explain how the effectiveness of antiseptics or disinfectants is altered by concentration, length of exposure, temp, pH and surface materials?
concentration-generally higher concentrations produce more rapid death.
LOE-varies depending on the microbes in question, typically longer the greater teh antimicrobial acitivity
Temp-increased temp=increased rate of chemical reactions which destroys microbes
pH-extreme pH are harmful to many microbes and enhance antimicrobe action
surface material-if found on blood pus etc-combination will yeild a reduction in the antimicrobe action
Which antimicrobial agent was most effective?
iodine followed by H2O2 (3% hydrogen peroxide)
Which organisms was most susceptible?
which organism was least susceptible to antimicrobial agents?
How can u calculate the CFU/g of a food substance?
count the number of colonies on plate <30 TFTC, >300 TNTC, mutilply # of colonies by dilution factor.
Do u expect food products to contain microbes? Why?
yes, food contains microbes because food contain organic nutrients that provide an excellent medium to support the growth and multiplication of microbes.
if foods contain microbes, does that mean that the food is contaminated or unsafe? Why?
no, some microbes are completely harmless post ingestion, they can be beneficial
Which food substances contained the largest numbers of microbes? Which contained the least?
Ground beef (liver) contained the most.
dried fruits (raisin) contained the least
Milk is pasteurized prior to sale. does this affect the way you view the numbers of microbes present in the milk sample?
yes, without psaeurization there wuld be alot more bacteria in milk including harmful coliforms.
Why use EMB?
emb medium permits the differentation b/w enteric lactose fermenters and nonfermenters as well as ID of the colon bacillus E. Coli with a metallic green sheen
Why are ground meat products likely to contain more enteric bacteria than many other foods sources?
perfect medium of nutrients for enteric bactera as opposed to the dried fruits which lack the rich ingrediants.
specific test for detection of coliforms, ac bacteria that is capable of using lactose as a carbon source producing acid and gas. gives an idea of the MPN
assures that the bacteria found are coliforms. uses selective and differnetial media EMB or Endo, streaked with the positive lactose fermenters. inhibits gram+ organisms and tests mainly for E. coli a positive indicator of feca pollution.
What is the MPN
the most probable number of coliforms present in the water.
How can u determine the MPN of a water sample?
estimated by determining the number of tubes n each group that shows a gas post incubation
Why use EMB as a confirmed test. What does a + test result look like on EMB?
b/c of its differential and selective properties. inhibits the growth of gram + bacteria and turns metallic green in the presence of E. coli
What is the role of the Durham tube?
detects gas formation by collecting gas bubbles.
What media is used fro determining the MPN?
Which types of water smaples are more likely to be contaminated with enteric bacteria? why?
sewage water, bogs and swamps. b/c sewage contains feces, and bogs and swamps are stagnat.
What type of bacteria are commonly found in the mouth?
lactobacillus acidophilus, streptocoocus mutans and actinomyces odontolyticus
What is the function of dextransucrase?
enzyme secreted by S. Mutans, polymerizes sucrose into a large polymer, dextran and the monosaccharide fructose. clings to teeth and forms plaque.
What is dextran, which oral bacteria produces it?
a sugar slime that contributes to dental caries, produced by S. Mutans.
When sucrose is broken down into glucose and fructose, what happens to the glucose? what happens to the fructose>
the form organic acids mainly lactic acid which decalcifies and softedn the enamel causing gingivitis.
What is the pH indicator used in the snyder test?
What information does the synder test provide
measures the amount of acid produces by the action of the lactobacilli on glucose.
incomplete lysis=green speckeled appearance on blood agar, S. Pneumoniae
lysis of RBC=smooth spreading that is yellow, S. Pyogenes
What organism is grown on chocolate agar? how is it recongnizable?
Neisseria spp. will turn pink to dark purple with the addition of p-aminodimethylaniline
What is the purpose of the candle jar?
What organism is detected on MSA? how does it appear?
Pathogenic S. aureus, turns yellow surrounding the growth.
What does a yellow discoloration on MSA mean? what is fermented?
fementation of mannitol.
What organism grows on Sabouraud agar?
both contain staphylococcus, streptococcus, both have alpha and non-hemolytic properties, entericocco and diptheroids. differnces throat is S. pneumoniae, skin is S. epidermis, skin also yeast and fungi, throat -moraxella and neisseria adn haemophlius.
throat and skin
What illnesses are associated with staphylococcus aureus?