Effect of Temperature in Salmonella Growth

1
Effect of Temperature in Salmonella Growth
Number of Salmonella per gram
50oF (10o C)
95oF (35o C)
44oF (6.7o C)
42oF (5.5o C)
4
5
3
2
1
Days
2
Incubation Periods
Cooked ham, meat, eggs, sauces and gravies
Staphylococcus aureus
2-4 hours
Clostridium perfringens
12 hours
Cooked meats, gravy
12-36 hours
Meat, poultry, eggs
Salmonella
Canned foods, smoked fish
Clostridium botulinum
12-36 hours
Vibrio parahemolyticus
Raw fish, shellfish
12 hours
Contaminated by carrier, not foodborne
24-48 hours
Shigella
Fever
3
National Data on Etiology of Foodborne Illness
Agent
Bacteria (40 agents)
68.7
Salmonella
25.0
Staph. aureus
12.7
Clostridium perfringens
10.0
Clostridium botulinum
9.5
Viral (11 agents)
9.4
Parasites (31 agents)
0.5
1.8
Fungal (16 agents)
Plants (36 agents)
-
Fish (28 agents)
12.3
Chemicals (28 agents)
7.3
4
Investigating an Epidemic Oswego, NY
On April 19, 1940, the local health officer in
the village of Lycoming, Oswego County, New York,
reported the occurrence of an outbreak of acute
gastrointestinal illness to the District Health
Officer in Syracuse.  Dr. A. M. Rubin,
epidemiologist-in-training, was assigned to
conduct an investigation.

When Dr. Rubin arrived in the field, he learned
from the health officer that all persons known to
be ill had attended a church supper the previous
evening, April 18.  Family members who had not
attended the church supper had not become ill. 
Accordingly, the investigation was focused on the
circumstances related to the supper.
5
Interviews regarding the presence of symptoms,
including the day and hour of onset, and the food
consumed at the church supper, were completed on
75 of the 80 persons known to have been present. 
A total of 46 persons who had experienced
gastrointestinal illness were identified. Q
Is this an Epidemic? Endemic for the region?
Due to seasonal variation? Due to random
variation?
6

• Select the correct case definition
• and find the error in the others
• All participants in the Oswego church supper held
  in the basement of the church in Lycoming, Oswego
  County, New York, on April 18, 1940, between 600
  PM and 1100 PM whether they attended church or
  not whether they participated in food
  preparation, transport, or distribution or not
  whether they ate or not.
• Persons who developed acute gastrointestinal
  symptoms within 72 hours of eating supper on
  April 18, 1940, and who were among attendees of
  the Lycoming, Oswego Church supper.
• Church members who developed acute
  gastrointestinal symptoms within 72 hours of the
  church supper held in Lycoming, Oswego on April
  18, 1940.

7

• Select the correct case definition
• and find the error in the others
• All participants in the Oswego church supper held
  in the basement of the church in Lycoming, Oswego
  County, New York, on April 18, 1940, between 600
  PM and 1100 PM whether they attended church or
  not whether they participated in food
  preparation, transport, or distribution or not
  whether they ate or not.
• Persons who developed acute gastrointestinal
  symptoms within 72 hours of eating supper on
  April 18, 1940, and who were among attendees of
  the Lycoming, Oswego Church supper.
• Church members who developed acute
  gastrointestinal symptoms within 72 hours of the
  church supper held in Lycoming, Oswego on April
  18, 1940.

8

• Select the correct case definition
• and find the error in the others
• All participants in the Oswego church supper held
  in the basement of the church in Lycoming, Oswego
  County, New York, on April 18, 1940, between 600
  PM and 1100 PM whether they attended church or
  not whether they participated in food
  preparation, transport, or distribution or not
  whether they ate or not. Missing definition of
  sickness
• Persons who developed acute gastrointestinal
  symptoms within 72 hours of eating supper on
  April 18, 1940, and who were among attendees of
  the Lycoming, Oswego Church supper. CORRECT
• Church members who developed acute
  gastrointestinal symptoms within 72 hours of the
  church supper held in Lycoming, Oswego on April
  18, 1940. Did not specify that they went to the
  dinner

9
Incidence of Cases of Diarrhea Among People
Attending Lycoming,Oswego Church Supper, June 1940
10
The supper was held in the basement of the
village church.  Foods were contributed by
numerous members of the congregation.  The supper
began at 600 PM and continued until 1100 PM. 
Food was spread out upon a table and consumed
over a period of several hours.
11
Church Supper Menu
Main Dishes Baked ham Spinach Mashed potatoes Cabbage salad Fruit Salad
Side Dishes Jello Rolls Brown Bread
Desserts Cakes Vanilla Ice Cream Chocolate Ice Cream
Beverages Milk Coffee Water
12
Which menu item(s) is the potential culprit? To
find out, calculate attack rates. The foods that
have the greatest difference in attack rates may
be the foods that were responsible for the
illness.
13
Attack Rates by Items Served Church Supper,
Oswego, New York April 1940
Number of persons who did not eat specified item
Number of persons who ate specified item
Attack rate ()
Attack rate
Well
Ill
Well
Ill
Total
Total
29
12
17
46
17
29
Baked ham
32
12
20
43
17
26
Spinach
37
14
23
37
14
23
Mashed potato
47
19
28
28
10
18
Cabbage salad
52
22
30
23
7
16
Jello
38
13
25
37
16
21
Rolls
48
20
28
27
9
18
Brown bread
71
27
44
4
2
2
Milk
44
17
27
31
12
19
Coffee
51
18
33
24
11
13
Water
35
16
19
40
13
27
Cakes
Ice cream (van)
21
18
3
54
11
43
Ice cream (choc)
27
7
20
47
22
25
69
27
42
6
2
4
Fruit salad
14
Attack Rates by Items Served Church Supper,
Oswego, New York April 1940
Number of persons who ate specified item
Number of persons who did not eat specified item
Attack rate ()
Total
Attack rate
Total
Well
Ill
Well
Ill
59
29
12
17
63
46
17
29
Baked ham
62
32
12
20
60
43
17
26
Spinach
Mashed potato
62
37
14
23
62
37
14
23
60
47
19
28
64
28
10
18
Cabbage salad
58
52
22
30
70
23
7
16
Jello
66
38
13
25
57
37
16
21
Rolls
58
48
20
28
67
27
9
18
Brown bread
62
71
27
44
50
4
2
2
Milk
61
44
17
27
61
31
12
19
Coffee
65
51
18
33
54
24
11
13
Water
54
35
16
19
67
40
13
27
Cakes
14
21
18
3
80
54
11
43
Ice cream (van)
Ice cream (choc)
27
7
20
53
47
22
25
74
61
69
27
42
67
6
2
4
Fruit salad
15
Attack Rates by Items Served Church Supper,
Oswego, New York April 1940
Number of persons who ate specified item
Number of persons who did not eat specified item
Total
Well
Ill
Well
Ill
Attack rate
Total
Attack rate ()
59
29
12
17
63
46
17
29
Baked ham
62
32
12
20
60
43
17
26
Spinach
Mashed potato
62
37
14
23
62
37
14
23
Cabbage salad
60
47
19
28
64
28
10
18
7
58
52
22
30
70
23
16
Jello
66
38
13
25
57
37
16
21
Rolls
67
58
48
20
28
9
18
Brown bread
27
62
71
27
44
50
4
2
2
Milk
19
61
44
17
27
61
31
12
Coffee
24
65
51
18
33
54
11
13
Water
54
35
16
19
67
40
13
27
Cakes
3
Ice cream (van)
14
21
18
80
54
11
43
74
27
7
20
53
47
22
25
Ice cream (choc)
61
69
27
42
67
6
2
4
Fruit salad
16
Attack Rate by Consumption of Vanilla Ice Cream,
Oswego, New York April 1940
Attack Rate ()
Total
Well
Ill
Ate vanilla ice cream?
79.6
54
11
43
Yes
14.3
21
18
3
No
61.3
75
29
46
Total

• The relative risk is calculated as 79.6/14.3 or
  5.6
• The relative risk indicates that persons who ate
  vanilla ice cream were 5.6 times more likely to
  become ill than those who did not eat vanilla ice
  cream

17
Conclusion

• An attack of gastroenteritis occurred following a
  church supper at Lycoming
• The cause of the outbreak was most likely
  contaminated vanilla ice cream

18
Surveillance

• Ongoing systematic collection, collation,
  analysis and interpretation of data and the
  dissemination of information to those who need to
  know in order that action may be taken.
• World Health Organization

19
Purposes of Public Health Surveillance

• Estimate magnitude of the problem
• Determine geographic distribution of illnesses
• Portraying the natural history of disease
• Detect epidemic / Define a problem
• Generate hypotheses and stimulate research
• Evaluate control measures
• Monitor changes in infectious agents
• Detect changes in health practice
• Facilitate planning

CDC
20
Passive Surveillance

• Physicians, laboratories, and hospitals are given
  forms to complete and submit with the expectation
  that they will report all of the cases of
  reportable disease that come to their attention
• Advantages Inexpensive
• Disadvantages Data are provided by busy health
  professionals. Thus, the data are more likely to
  be incomplete and underestimate the presence of
  disease in the population

21
Active Surveillance

• Involves regular periodic collection of case
  reports by telephone or personal visits to the
  reporting individuals to obtain the data
• Advantages More accurate because it is
  conducted by individuals specifically employed to
  carry out the responsibility
• Disadvantages Expensive

22
Sentinel Surveillance

• Monitoring of key health events, through sentinel
  sites, events, providers, vectors/animals
• Case report indicates a failure of the health
  care system or indicates that special problems
  are emerging
• Advantages Very inexpensive
• Disadvantages Applicable only for a select
  group of diseases

23
Some Surveillance Programs

• National Notifiable Diseases Surveillance System
• http//www.cdc.gov/epo/dphsi/nndsshis.htm
• Morbidity and Mortality Weekly Report (MMWR)
• http//www.cdc.gov
• Cancer Surveillance, Epidemiology and End Result
  (SEER)
• http//www.seer.cancer.gov/

24

• Good surveillance does not necessarily ensure
  the making of right decisions, but it reduces the
  chances of wrong ones.
• Alexander D. Langmuir
• NEJM 1963268182-191