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MICROBIOLOGY - ALCAMO CHAPTER 24: MICROBIOLOGY OF FOODS.

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Presentation on theme: "MICROBIOLOGY - ALCAMO CHAPTER 24: MICROBIOLOGY OF FOODS."— Presentation transcript:

1 MICROBIOLOGY - ALCAMO CHAPTER 24: MICROBIOLOGY OF FOODS

2 Case of the Patty Melt The 3 rd largest _________________in our country occurred in October, 1983, at the _____________ ________________________________ Between October 14 th and 16 th, 36 people began to feel the _______________________________ _______________________________________ All had to ____________________, and all but one person ____________________

3 Case of the Patty Melt Investigators from the __________ came to investigate They identified the _________________ _________________________________ But, they had to determine ____________ __________________________________ They were able to isolate _____________ __________________________________

4 Case of the Patty Melt Once sautéed, the onions were left ___________________________________ The onions had ______________________ ___________________________________ ____________________in the __________________of warm onions and _________ _________________________

5 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

6 Food Spoilage Has been a problem since humans started __________________________________ __________________________________ Marco Polo explored new trade routes to get __________________________________ __________________________________ _________________________ were not yet invented

7 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 ___________________________________

8 ENTRY OF MO’S TO FOOD _______ – MO’s fall onto fruit and vegetables and _______________________ ___________________________________ ______ – crops carry __________________ ___________________________________ _____________________– transport MO’s on their ____________________________ _____________________________________

9 ENTRY OF MO’S TO FOOD _______________– processing and storage –Careless butcher – can ___________________ ______________________________________ –Raw fruits and vegetables – _______________

10 Factors Affecting Growth of MO’s ___________: Food must be __________ ______________________ ______________________ MO’s do not grow in foods like ___________________________ _________________________________

11 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

12 Factors Affecting Growth of MO’s ______________________: It may be ___________________________ _____________________________________ MO’s have a harder time ______________ ___________________________________ Mo’s can exist within the _____________ _______

13 Factors Affecting Growth of MO’s Chemical Composition of Food: _______________________ _______________________ – found on fruits _______________________ __________– found on meats ___________________________might encourage MO’s to grow and __________ __________________________________

14 Factors Affecting Growth of MO’s _____________: __________________(all oxygen removed) do not support the growth of ____________ __________________________________ __________________________________ ____________________________________

15 Factors Affecting Growth of MO’s ____________________: The refrigerator is ________________ _________________________________ A hot warehouse storeroom would _______________________________

16 Chemistry of Spoilage Spoilage often due to __________________ ___________________________________ –Yeasts – ______________________________ ______________________________________ –Certain bacteria – _______________________ _______________________________________ –Carbohydrates can break down into _________________________

17 Chemistry of Spoilage –In General: ______________________________ ____________

18 Food Industry Divides Food By Its Properties ______________________– Spoil rapidly Examples: _____________________________ ____________________________________

19 Highly Perishable ___________________– muscle tissue of animals usually sterile Spoilage usually occurs during __________ ___________________________________ ___________________________handled so often _______________– less compact tissue and ____________________________

20 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

21 Food Industry Divides Food By Its Properties ___________________________________ Examples: ________________________ ______________________________

22 Food Industry Divides Food By Its Properties ___________________________________ _______________________________________ __________________________________

23 Breads and Bakery Products _______________________are the sources of spoilage Most contaminants _____________ _____________________________ _______________________are also excellent for bacterial growth Most bakery products _________________ ___________________________________

24 Grains 1. The mold ________________ __________________________ –These toxins are associated with ___________ ______________________________________ 2. The fungus ________________________ ___________________________________ –These toxins may _______________________ ______________________________________ –The drug ______________________________

25 Food Preservation Centuries ago humans learned that they could preserve food –___________________________________________ In the mid 1700’s ________________________ _______________________________________ Several generations later __________________ ______________________________________ The purpose remains the same – ______________ ________________________________________ ________________________________________

26 Heat Kills MO’s by _______________________ Useful in the _____________________: –Machines ___________________________ –Subject food to _______________________ ____________________________________ –Food is ______________________________ –Containers ___________________________ Process designed to _________________ ___________________________________ ___________________________________

27 If canning is not done properly, __________ _____________________________________ They _______________________________ _____________________________________

28 Low Temperatures ___________________________________ Organisms are _______________________ ___________________________________ Modern refrigerator operates at about 5 C –______________________________________ ______________________________________ –But,___________________________________ ______________________________________

29 Low Temperatures Freezer _____________________________ ___________________________________ But, _______________________________ ___________________________ –___________________ ______________________is best Food should _________________because the bacteria ________________________ __________________________________

30 TEMPERATURE

31 Drying Food Dried foods have ___________ ___________________________ Used to __________________ _________________________________ – now there are machines ___________________________________ bacteria resist drying and can survive to spoil the product once ________________

32 Osmotic Pressure ____________________________________, the food ___________________________ Mo’s ______________________ Salted foods –____________________________ Sugared foods –____________________________

33 Chemical Preservatives Must _______________________________ ___________________________________ ___________________________________ Smoking foods ______________________ ___________________________________ ___________________________________ Major group of chemical preservatives are the ________________ –_____________________________________

34 Chemical Preservatives Some foods have their _________________ ___________________________________ There are antimicrobial substances in: –______________________________________

35 Radiation ____________– _________________ ____________________________emitted by the radioactive isotope – cobalt 60 –The radiations are not radioactive and _______ ______________________________________ They _______________________________ ___________________________________ –Can cause the __________________________ ______________________________________ –Maybe form new and toxic chemicals??

36

37 Foodborne Disease _______________– Person affected by an _________________________ –Bacterial – _______________________ ________________________________ –Protozoal – ____________________________ –Viral – _____________________________ ____________________________– Person affected by _________________________ –_____________________________________ _____________________________________

38 Preventing Foodborne Disease In the U.S. _________________________ ___________________________________ Can avoid them by taking basic precautions –_____________________________________ –_________________________ –_________________________ _________________________

39 WASH CUTTING BOARD CAREFULLY

40 WASH HANDS

41 Preventing Foodborne Disease _____________ are implicated the most so ______________ ________________________ ________________________ _______________________ –Don’t take _____________(cream pies, salads) –___________________________________– a different one from the grill

42 FOODS FROM MO’S __________________: –_____________________________ _____________________________ –Bacteria _______________ _______ _____________________________ (yogurt and cheese)

43 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

44 FOODS FROM MO’S Other Foods: –_____________________ –__________________


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