Download Lecture 27

Lecture 27:
Avoiding Food-Borne
Pathogens
Nutrition 150
Shallin Busch, Ph.D.
Symptoms
• Onset can be between 1 hr and 50 days
- Usually within a few days
• Common symptoms are abdominal pain,
nausea, cramping, vomiting, diarrhea, fever,
flu-like symptoms
• Rarer symptoms are bloody stools, liver
disease, kidney failure, nervous system
impairment
• Can cause death
Foodborne Illnesses
• Infection: Eating foods contaminated
with infectious microbes
– Salmonella, Campylobacter jejuni
• Intoxication: Eating foods
contaminated with natural toxins or
microbes that produce toxins
– Staphylococcus aureus, Clostridium
botulinum
Contamination and Society
• Historically, food borne illnesses occurred
in small settings and affected few people
• With more people eating food prepared and
packaged by others, the risk for epidemics
due to improper handling of food has
increased
– 80% of food borne illnesses are caused by
errors in commercial settings
Commercial Food Contamination
• Salmonella and Peter Pan peanut butter
– 290 ill, 46 hospitalized
• Listeria and tainted lunch meats
– Killed 15 people, made 100 others sick
• E. coli and fast or packaged food
– Green onions at Taco Bell
• 71 ill, 53 hospitalizes, 8 kidney failure
– Spinach in packages
• 199 ill, 102 hospitalized, 2 died
– The Jack and the Box in Seattle
Preventing Contamination
• Keep a clean, safe kitchen
• Avoid cross-contamination
– Using same utensils for raw and cooked foods
• Keep hot food hot
– Cooking meats to adequate temperature and
maintaining that temp. until serving
• Keep cold foods cold
• 400 fell ill, 3 small children died
Recommended Safe Temperatures (Fahrenheit)
180 ˚
Whole poultry
170 ˚
165 ˚
160 ˚
Poultry breast, well-done meats
145 ˚
140 ˚
Bacteria multiply
rapidly at temperatures
between 40˚ and 140˚ F.
40 ˚
0 ˚
Stuffing, ground poultry, reheat leftovers
Medium-done meats, raw eggs, egg dishes,
pork, ground meats
Medium-rare beef steaks, roasts, veal, lamb
Hold hot foods
DANGER ZONE: Do not keep foods between
40˚ F and 140˚ F for more than 2 hours.
Refrigerator temperatures
Freezer temperatures
Refrigerator Storage
1-2 Days: raw ground meats (including
sausage), raw fish and poultry,
gravies
3-5 Days: Raw steaks, roasts, or chops;
cooked meats, poultry, veggies, mixed
dishes; opened lunch meats;
mayonnaise salads
Refrigerator Storage
1 week: hard-cooked eggs, bacon, or hot
dogs; smoked sausages or seafood
2-4 weeks: raw eggs (in shells);
unopened lunch meats, bacon, hot
dogs; dry sausages; most aged and
processed cheeses
2 months: opened mayonnaise, most dry
cheese
Pasteurization
• Heat processing of food that inactivates
some, but not all, microorganisms in the
food (Whitney and Rolfes)
• Does not sterilize food
• Bacteria in pasteurized food can still cause
spoilage
• Milk, other dairy products, juices, beer
Irradiation
• Sterilizing a food by exposure to energy
waves, similar to UV light and microwaves
• Kills bacteria without heat (“cold
pasteurization”)
• Approved by FAO, WHO, American Medical
Association
• Does NOT make food radioactive
• Minimal vitamin loss
Irradiation cont.
• Some food change texture, odor, flavor
• Approved foods do not change taste,
texture or appearance:
– Eggs
– Raw beef, lamb, poultry, pork
– Spices and tea
– Wheat
– Vegetable like potatoes, tomatoes, onions
– Fresh fruit like strawberries, citrus, papaya
Why Irradiation?
• Controls mold in grains
• Destroys harmful bacteria
• Sterilizes spices and teas for storage
at room temp
• Controls insects
• Delays ripening and sprouting