Introduction to Human Nutrition

332 Introduction to Human Nutrition

Salmonella

Although there are approx.

2400 different

Salmonella

serotypes only a small number account for most human infections, with S.

Typhimurium and

S.

Enteritidis predominating. Undercooked food from infected food animals is most commonly implicated. Egg-associated salmonellosis is an important public health problem

(a) Usually

12–36 h, but may be 6–72 h

(b) 2–5 days

(a) Fever, abdominal

pain, diarrhea, nausea and sometimes vomiting. Can be fatal in older people or those with weakened immune system

(b) ~10

6 cells

(a) 7°C(b) 35–37°C(c) 4.0(d) 0.93

Heat-sensitive

(a) Gram

negative

(b) Facultative

anaerobe

(a) Water, soil, animal

feces, raw poultry, raw meats, and raw seafood

(b) Raw meats, poultry,

eggs, raw milk and other dairy products, raw fruits and vegetables (e.g., alfalfa sprouts and melons)

Vibrio cholerae

serogroup non-O1

Vibrio cholerae

non-O1 is

related to

V. cholerae

O1

(the organism that causes Asiatic or epidemic cholera), but causes a disease reported to be less severe than cholera. It has been generally believed that water was the main vehicle for transmission, but an increasing number of cases have been associated with food

(a) 1–3 days(b) Diarrhea

lasts 6–7 days

(a) Diarrhea, abdominal

cramps, fever, some vomiting, and nausea

(b)

>^10

6 cells

(a) 10°C(b) 37°C(c) 5.0(d) 0.97

Heat-sensitive

(a) Gram

negative

(b) Facultative

anaerobe

(a) Costal waters, raw

oysters

(b) Shellfi sh

Vibrio

parahaemolyticus

V. parahaemolyticus

can be

considered to be the leading cause of seafood-borne bacterial gastroenteritis. It is frequently isolated from fi sh from both marine and brackish-water environments

(a) 12–24 h(b)

<7 days

(a) Diarrhea, abdominal

cramps, nausea, vomiting, headache, fever, chills

(b)

>^10

6 cells

(a) 5°C(b) 37°C(c) 4.8(d) 0.94

Heat-sensitive

(a) Gram

negative

(b) Facultative

anaerobe

(a) Costal and

estuarine waters, raw shellfi sh

(b) Fish and raw

shellfi sh

Table 14.2

Continued

Bacteria

Comment

Food-borne illness

(a) Min. temp (b) Opt. temp (c) Min. pH

a

(d) Min. A

bw

Heat resistance

(a) Gram stain(b) Aerobic/anaerobic

(a) Source(b) Associated foods

b

(a) Onset(b) Duration

(a) Symptoms(b) Infectious dose