Meat Science Exam 3

Top 10 pathogens

1. Staphylococcus (from humans)

2. Salmonella (everywhere/polutry)

3. E. coli (beef/ruminats

4. Listeria (fruits/dairy)

5. Clostridium botulinum (canned food/neurotoxin)

6. Hepatitis A (dirty water)

7. Taenia solium (tapeworm)

8. Liver fluke

How many cases each year does CDC estimate are from food-born illness?

48 M cases

How many hospitalizations each year does CDC estimate are from food-born illness?

128,000 hospitalizations

How many deaths each year does CDC estimate are from food-born illness?

3,000 deaths

How much cost each year does CDC estimate are from food-born illness?

$6.9 B For top 5 foodborne pathogens

What direction does Monotrichous flagella come from? What is the use for this?

• Flagella comes one direction

• Can go through blood-brain barrier

• Use action myosin to travel

• Pass from mothers to babies in womb

Ex: L. Monocytogenea

What direction does Peritrichous flagella come from? What is the use for this?

Flagella comes from multiple directions

Ex: salmonella

Label the following structure on the bacteria (chromosomes, capsule, cell wall, plasma membrane, cytosol, ribosomes, food granule, flagella, plasmid, pili)

What is the function of plasmid?

It contains DNA that carries anti microbial genes for antibodies resistance

Layers of gram positive bacteria

1. Peptidoglycan (protein, sugar) thick/gram multilayer, purple

2. Periplasmic space (nutrients, cushion)

3. Plasma membrane

Layers of Gram Negative Bacteria

1. Lipopolysaccharide (lipid, many sugar) and protein

   1. Has PORIN (drugs/molecules enter cell through)

      1. Antibodies kill easily but cause release endotoxins

2. Periplasmic space

3. Peptidoglycan (mono layer/thin layer)

4. Periplasmic space

5. Plasma membrane

Ex: salmonella, E. coli.

Gram Staining Process ???

Fixation → crystal violet → iodine treatment → decolorisation → counter stain with safranin

• Crystal violet form covelent bond with iodine in cell

• Decolorisation (gram (-), loose color since it has thin Peptidoglycan layer) (gram (+) turns purple)

• Safranin stains pink in gram (-)

What are microbes?

microorganisms not visible to naked eye

Ex: bacteria, parasites, viruses and fungi

How often do bacteria multiple on average?

every 20 minutes 

In 6hrs 1 cell becomes 1 M cells

What are fungi?

Single, or multi-celled organisms such as yeast, mold, mushrooms

What are viruses?

Non-living, non-cellular organisms that require a host to grow

What are bacteria?

Living, single called organisms

What organisms are parasites?

1. Flatworms (taenia, round worms)

2. Round worms (anisakis)

3. Protozoa (eukaryotic, single-cell, motile)

How often do clostridium borfringens multiple and where are they found?

multiply every 9 minutes and thrive in anaerobic conditions (no oxygen) Ex: canned food, meats

-can cause can to be distorted from gas byproduct 

What do Rods, Cocci, and Spiral bacteria look like?

1. Rods - bacilli or diplobaccilli (2 rods)

2. Cocci - spherical, dipolococci (2 spheres)

3. Spiral - spirilla

What does pairs, clusters and chains bacteria look like? Give example of each

1. Pairs - enterococcus

2. Clusters - staphylococcus aureus

3. Chains - lactococuslactis 

What temperature do you cook food at to prevent clostridium bacteria from multiplying?

> 140 F -1hr→ 70 F -4 hrs→ <40 F (hold), total: 5 hrs , no more than 6

How long does it take CDC to be notified of food-borne illness outbreak?

Hospitalized (day 3) → Lab results out (day 5) → Presumptive positive (day 7) → people surveyed to find origin (takes 7-10 days)

Total time: 28 days until CDC notified

What is an infection?

Pathogen is ingested and living pathogen multiplies inside body

What is an Intoxication?

Pathogen produced toxins that were ingested

Toxin mediated infection

Living pathogen inside body and produces toxin in body

What does it mean to be susceptible?

inability to prevent or overcome invasion

What does it mean to be immunocompromised?

weak immune system from disease or treatments

Ex: old age, health (AIDs, cancer), pregnancy, nutritional status, meds

At what temperature and for how long should steak be cooked at?

145 F for 3 minutes or less of steak is sterile and handled by hygienic people

What does FATTOM standard for?

include factors of food that support microbial growth

Food, Acidity, Time, Temp, Oxygen level, Moisture

Which of the FATTOM are intrinsic factors?

Inside factors that affect microbial growth

Food, acidity, moisture

Which of the FATTOM are Extrinsic?

outside factors affecting microbial growth

Time, temp and oxygen level

How does pH affect bacteria?

Low pH (lots of H+) penetrated gram (-) bacteria through their PORIN and kill them, gram (+) has thicker membrane - more resistant to low pH

What is the pH for ideal pathogen growth, meat/poultry and prevent microbial growth?

ideal pH for pathogen: 4.6 - 7.5

pH of meat & poultry: 5.1 - 6.4

pH to prevent microbial growth: < 4.6

At what temperatures does pathogen grow? What temperature is recommended for storage, display, and transport of meat?

Pathogens grow at 41 F - 135 F

Meat should be kept at 28 F

Where is contamination is from?

Farm, commodity/ingredient/packaging/processing, retail, consumer

How does food become contaminated?

Contaminated ingredient or packaging material, improper processing (undercooking, bad cooling, bad holding), cross contamination, poor personal hygiene