Inhibition and destruction of MOs

Growth curve manipulation lethal agent

Accelerated effects, flat or no growth

1. flat curve-destruction

2. peak and steep decline, post heat decline

Growth curve mixed population

growth continues, mixed population results in equal number of sensitive and resistant cells, some may die while others proliferate (growth continues)

Growth curve end-product accumulation

growth declines as the produce builds up (ex. acid), becomes toxic for MOs, BUT a buffer can neutralize acid or substrate changes can be made (additional feedstock) to continue growth

Growth curve cell resistance due to biofilm formation

continuous growth

Most widely used method to kill and inhibit MOs + pathogens

ALWAYS heat treatment * will always be in HACCP, specific GMPs, and is always a critical control point

Thermal death time (TDT)

a measurement of time required to completely sterilize a suspension of bacterial cells and spores at a given temperature

Preservation and processing methods of using chemicals to kill MOs

1. Bactericide

2. Bacteriostat

Bactericide

complete death

sterilization

Bacteriostat

washing/sanitization

inhibition

big pic chemical and MO contam

we want to inhibit MOs with chemical preservatives BUT we do not want to replace one type of contamination with another

Chemical sanitizers are used because they are...

far cheaper for cleaning facilities when compared to steam cleaning or thermal sanitization

Newer method for killing MOs

Pressure

high pressure processing is used for prod like guac, hummus, non-pasteurized juice, coconut water, etc. heat-sensitive products

HPP crushes cells

Ways to kill a cell

1. Heat

2. Chemicals

3. Radiation

4. O2 removal

5. Pressure

Time temp control

keep hot food hot

keep cold food cold

keep frozen food frozen

TCS

temperature control for safety foods

TCS foods specific example

hot rotisserie chicken is sold on hot stand, not in fridge, must be kept hot

TCS food categories

red meat/ poultry

cooked meat products (home-made stromboli is not at farmers market)

milk/dairy products (cream-filled donut)

raw shell eggs (must be in cooler with thermometer)

fish/shellfish

cooked rice, potato, pasta

raw seed sprouts, soy products

cut produce (sliced tomato, cubed cantaloupe)

garlic/oil mixtures (clost. botulinum)

Constant temp checking is required for ...

TCS foods

Temp checks

delivery = each time it arrives

storage = once minimum

fridge/ refrigerated display/ freezer = daily at least

dry = periodically

thawing = whenever thawed

cooking = cooked

cooled = cooled

reheated = reheated

hot holding = frequently throughout

cold holding = frequently

Holding temps

Hot holding 57C (135F) or above

DANGER between hot/fridge

Fridge 5C

Frozen -18C (0F)

objective of food holding is to...

minimize time in the danger zone, for example if rotisserie were to be stored in a fridge it would need to be blast cooled to minimize time in the danger zone

When to calibrate thermometers (6)

1. before and after first use

2. at regular interval, daily or more depending on crit. control.

3. after damage (drop, etc)

4. funny reading

5. after confirmed foodborne illness connected to temp abuse

6. after sanitization/ between food products

two ways to calibrate thermometers

boiling water

ice water