Microbiology

Describe the differences between spores and vegetative cells.

Vegetative cells are metabolically active and relatively heat-sensitive. Spores are dormant, highly resistant to heat, chemicals, and desiccation, and are critical food safety concerns due to their survival through processing.

Name 3 food poisoning microorganisms present in seafood.

Vibrio cholerae, vibrio parahaemolyticus, vibrio vulnificus, yersinia ruckeri, aeromonas hydrophila, etc

Answer the following about Listeria monocytogenes: Why is it a concern in refrigerated foods? Name three food categories commonly associated with outbreaks. Describe one control strategy used in food processing environments.

Why it is a concern in refrigerated foods: Listeria is psychrotrophic, meaning it can grow at refrigeration temperatures. Food categories commonly associated with outbreaks (any three): Ready-to-eat deli meats, Soft cheeses (especially unpasteurized), Smoked seafood, Pre-cut fruits and vegetables One control strategy: Environmental monitoring programs in processing facilities, Use of post-lethality treatments (e.g., HPP), Strict sanitation and separation of raw and RTE areas

Which microorganisms make the following hydrocolloids? Xanthan gum, curdlan, gellan gum

Xanthan - xanthomonas campestris, curdlan - alcaligenes faecalis var. myxogenes, gellan - pseudomonas elodea

Name 2 food born pathogens that can grow at refrigerator temperatures.

Yersinia enterocolitican, aeromonas hydrophilia, listeria monocytogenes

Define the D-value and the Z-value.

Z-value – temperature required to decrease the time necessary to obtain a 1 log reduction in cell number to 1/10th of the original value D-value – the time in minutes at a specific temperature to reduce the number of microogranisms by 1 log cycle, AKA kill 90% of micorbes.

Which of the following four choices do you need to include in developing a Standardized Recipe for a HACCP system? a) Critical Control Points; b) Cost Per Portion; c) Cooking Methods; d) Ingredients

A

Which mycotoxin is associated with liver cancer? a. aflatoxin b. ochratoxin c. patulin

a. aflatoxin

Which Aflatoxin is the most carcinogenic? a. B1, b. G1, c. G2, d. M1

a. B1

Which of the following foodborne illnesses is not caused by preformed toxins ingested from contaminated food? A. Infant botulism B. Staphylococcal food poisoning C. Bacillus cereus emetic syndrome D. Foodborne botulism

A. Infant botulism

In determining the effect of combining two antimicrobials, what does a fractional inhibitory concentration index of 0.4 signify? A. Syngergy B. Partial synergy C. Indifference D. Antagonism

A. Synergy

In a foodservice establishment, the function of an air curtain is to: a) form a shield of air that flying insects avoid; b) keep freezer and refrigerator temperatures constant; c) serve as a substitute door in the receiving area; d) prevent cockroaches and mice from entering the facility

a) Form a shield of air that flying insects avoid

In predictive food micro, growth rate is calculated by linear or non-linear regression on 'log of counts vs. time plot'. which model cannot be used for calculating growth rate: A.logistic model, B. Arrhenius model, C.Gompertz model, D.baranyi model?

Arrhenius model

Which medium is used to detect and enumerate Staphylococcus aureus directly in foods? A. apt agar, B. Baird-Parker agar, C. Potatoe dextrose Agar, D. Violet red bile agar

B. Baird-Parker Agar

Which is not a property of the muscle protein collagen? a. white color b. elastic c. heat degradable

b. elastic

Which of the following denotes the correct way to type the name of a bacteria genus and species: A.genus name and species name capitalized, B.genus name capitalized and species lower-case, C.genus and species both lower-case, or D.none of the above?

B. genus name capitalized, species name lower-case

Which is not an agent of paralytic shellfish poisoning? A. Saxitoxin B. Parasaxotoxin C. Neosaxotoxin D. Gonyautoxins (GTX) E. Decarbamoylsaxitoxin

B. Parasaxitoxin

Which of the following ingredients are most responsible for myofibrillar protein solubilization during sausage processing? A.nitrite anderythorbate B.salt and phosphate C.glucono delta lactone and nonfat dry milk D.spices

B. salt and phosphate

Adverse reaction to a food or food component that occurs through unknown mechanisms even including psychosomatic illnesses is called: A.food anaphylaxis, B.food idiosyncrasy, or C.metabolic reaction?

B.food idiosyncrasy

Of the following pathogens, which one was recognized even 30 years ago: campylobacter jejuni, Listeria monocytogenes, Bacillus cereus, Cyclospora cayetanensis?

Bacillus cereus