MICROBIOLOGY - ALCAMO

CHAPTER 24: MICROBIOLOGY OF FOODS

Case of the Patty Melt

• The 3rd largest _________________in our country occurred in October, 1983, at the _____________

• ________________________________• Between October 14th and 16th, 36 people began to

feel the _______________________________• _______________________________________• _______________________________________• All had to ____________________, and all but

one person ____________________

Case of the Patty Melt

• Investigators from the

__________ came to investigate

• They identified the _________________

• _________________________________

• But, they had to determine ______________________________________________

• They were able to isolate _____________

• __________________________________

Case of the Patty Melt

• Once sautéed, the onions were left ___________________________________

• The onions had _________________________________________________________

• ____________________in

the __________________of

warm onions and _________

_________________________

Why Did It Happen??

• Most foods (even cooked foods) ____________________________________________

• There is plenty of __________________________________________________________________________________________

• We will be talking about _______________ that contaminate food, the ______________ of them, and how to prevent them

Food Spoilage

• Has been a problem since humans started __________________________________

• __________________________________

• Marco Polo explored new trade routes to get __________________________________

• __________________________________

• _________________________ were not yet invented

Food Spoilage

• Food is considered spoiled if it

is __________________________

• Usually it will have an _________

• ____________________________

• Sometimes you can’t tell if there ___________________________________________

• Consumption of toxins or MO’s can cause a ___________________________________

ENTRY OF MO’S TO FOOD

• _______ – MO’s fall onto fruit and vegetables and __________________________________________________________

• ______ – crops carry _____________________________________________________

• _____________________– transport MO’s on their ____________________________

_____________________________________

ENTRY OF MO’S TO FOOD

• _______________– processing and storage– Careless butcher – can ___________________

______________________________________– Raw fruits and vegetables – _______________

Factors Affecting Growth of MO’s

___________:• Food must be __________

____________________________________________

• MO’s do not grow in foods

like ___________________________

_________________________________

Factors Affecting Growth of MO’s

_______:• Most foods are _________

_____________________

• Many bacteria grow well

under these conditions

• If food pH is below 5.0 ________________

• __________________________________– usually mold

Factors Affecting Growth of MO’s

______________________:• It may be ___________________________

_____________________________________

• MO’s have a harder time _________________________________________________

• Mo’s can exist within the _____________

• _______

Factors Affecting Growth of MO’s

Chemical Composition of Food:• _______________________

_______________________ – found on fruits

• _________________________________– found on meats

• ___________________________might encourage MO’s to grow and ____________________________________________

Factors Affecting Growth of MO’s_____________:

• __________________(all oxygen removed) do not support the growth of ______________________________________________

• __________________________________

____________________________________

Factors Affecting Growth of MO’s

____________________:

• The refrigerator is ________________

_________________________________

• A hot warehouse storeroom would _______________________________

Chemistry of Spoilage

• Spoilage often due to _____________________________________________________– Yeasts – ______________________________

______________________________________– Certain bacteria – _______________________

_______________________________________– Carbohydrates can break down into

• _________________________

• _________________________

Chemistry of Spoilage

– In General:

• ______________________________

• ______________________________

____________

Food Industry Divides Food By Its Properties

______________________– Spoil rapidly

Examples: _________________________________________________________________

Highly Perishable

• ___________________– muscle tissue of animals usually sterile

• Spoilage usually occurs during _____________________________________________

• ___________________________handled so often

• _______________– less compact tissue and ____________________________

Highly Perishable

• __________________________– contamination is usually from MO’s that have ___________________________

• ___________________________________– passed on to consumers via poultry and egg products

• ________________________, but shell can get penetrated by bacteria after a few hours

Food Industry Divides Food By Its Properties

___________________________________

Examples: ______________________________________________________

Food Industry Divides Food By Its Properties

__________________________________________________________________________

__________________________________

Breads and Bakery Products

• _______________________are the

sources of spoilage

• Most contaminants __________________________________________

• _______________________are also excellent for bacterial growth

• Most bakery products ____________________________________________________

Grains

• 1. The mold __________________________________________– These toxins are associated with ___________

______________________________________

• 2. The fungus ___________________________________________________________– These toxins may _______________________

______________________________________– The drug ______________________________

Food Preservation• Centuries ago humans learned that they could

preserve food– ___________________________________________

• In the mid 1700’s _______________________________________________________________

• Several generations later ________________________________________________________

• The purpose remains the same – ______________________________________________________________________________________________

Heat• Kills MO’s by _______________________

• Useful in the _____________________:– Machines ___________________________– Subject food to _______________________

____________________________________– Food is ______________________________– Containers ___________________________

• Process designed to _______________________________________________________________________________________

• If canning is not done properly, _______________________________________________• They ____________________________________________________________________

Low Temperatures

• ______________________________________________________________________

• Organisms are __________________________________________________________

• Modern refrigerator operates at about 5 C– ______________________________________

______________________________________– But,___________________________________

______________________________________

Low Temperatures

• Freezer ________________________________________________________________

• But, __________________________________________________________– ___________________– ___________________

• ______________________is best• Food should _________________because the

bacteria __________________________________________________________

TEMPERATURE

Drying Food

• Dried foods have ___________

___________________________

___________________________

• Used to __________________

_________________________________

– now there are machines

• ___________________________________bacteria resist drying and can survive to spoil the product once ________________

Osmotic Pressure

____________________________________, the food ___________________________

• Mo’s ______________________

• Salted foods– ____________________________

• Sugared foods– ____________________________

Chemical Preservatives• Must

_____________________________________________________________________________________________________

• Smoking foods ____________________________________________________________________________________________

• Major group of chemical preservatives are the ________________– _____________________________________

Chemical Preservatives• Some foods have their _________________

___________________________________

• There are antimicrobial substances in:– ______________________________________– ______________________________________– ______________________________________

Radiation• ____________– _________________

____________________________emitted by the radioactive isotope – cobalt 60– The radiations are not radioactive and _______

______________________________________

• They __________________________________________________________________– Can cause the __________________________

______________________________________– Maybe form new and toxic chemicals??

Foodborne Disease• _______________– Person affected by

an _________________________– Bacterial – _______________________

________________________________– Protozoal – ____________________________– Viral – _____________________________

• ____________________________– Person affected by _________________________– _____________________________________

_____________________________________

Preventing Foodborne Disease

• In the U.S. ____________________________________________________________

• Can avoid them by taking basic precautions– _____________________________________– _____________________________________– _________________________– _________________________– _________________________– _________________________

_________________________

WASH CUTTING BOARD CAREFULLY

WASH HANDS

Preventing Foodborne Disease

• _____________ are implicated

the most so ______________________________________________________________

• _______________________– Don’t take _____________(cream pies, salads)– ___________________________________– a

different one from the grill

FOODS FROM MO’S• __________________:

– __________________________________________________________

– Bacteria _______________ ____________________________________ (yogurt and cheese)

FOODS FROM MO’S• __________________:

– 1. less vulnerable to _____________________– 2. less likely to be _______________________– 3. sour taste has been ____________________

______________________________________– ___________ – Leuconostoc and Lactobacillus– ______________ – Enterobacter, Leuconostoc

and Lactobacillus– _____________ – Acetobacter aceti

FOODS FROM MO’S

• Other Foods:– _____________________– _____________________– _____________________– __________________