Journal of Animal Research: v.5 n.1, p. 85-93. April. 2015
DOI Number: 10.5958/2277-940X.2015.00014.5
Growth Dynamics of Salmonella, Isolated from Different Sources,
at different Temperature and pH
M.A. Malik 1 , S.K. Kotwal 1 , M. Rashid 1 , H.K. Sharma 1 , M. Singh 1 and Neelesh Sharma 2*
1 Division of Veterinary Public Health & Epidemiology, F.V.Sc. & A.H., SKUAST-J, R.S. Pura, Jammu, INDIA
2 Division of Veterinary Medicine, F.V.Sc. & A.H., SKUAST-J, R.S. Pura, Jammu, INDIA
*Corresponding author: N. Sharma; Email:
Received: 02 March, 2015
Accepted: 02 April, 2015
A total of 350 samples 50 each from raw poultry meat, poultry cloacal swabs and human diarrheic cases, besides 200 eggs were
processed for the isolation of Salmonella. Effect of varying temperature and pH on growth of Salmonella isolates was evaluated
by growing the organism in Brain Heart Infusion Broth at 4, 10, and 30 ° C with pH values of 4.5, 5.5 and 6.5. At 10°C, the mean
generation time of the isolates at pH values of 4.5, 5.5 and 6.5 was 44.23 ± 0.44, 15.51 ± 0.08 and 10.23 ± 0.10 hrs, respectively,
while at 30°C, the generation time of the isolates at pH values of 4.5, 5.5 and 6.5 was 126.10 ± 0.68, 59.96 ± 0.14 and 36.22 ±
0.07 min, respectively. No growth observed at 4 ° C, at any given pH value. As the temperature and pH were lowered, significant
increase in generation time of the organism was observed.
Keywords : Salmonella , growth, temperature, pH.
The genus Salmonella is a typical member of the family
are contaminated poultry, pork, beef, eggs and milk (Acha
Enterobacteriaceae and consists of Gram -ve, oxidase -ve,
and Szyfres, 2003).
straight sided rod shaped bacteria which are castalase +ve,
Salmonellae can grow over a wide range of temperature,
and have both a respiratory and a fermentative metabolism
pH, and a in good culture medium rather in a poor one.
of carbohydrates. Most Salmonellae are motile by
For example, minimal temperatures for growth in food
peritrichous flagella. More than 2,500 Salmonella serovars
range from 6.7 to 7.8°C in chicken to over 10°C in custard
have been identified, most belonging to the species
and ham salad. They grow well at room temperature, but
Salmonella bongori and Salmonella enterica . Based on
optimum temperature for their growth is about 37°C and
pathogenesis, S. enterica can be divided into two broad
maximal temperature at which they can grow is about
groups, Group 1 consists of a large number of serovars,
45.6°C. The pH range for their growth is 4.1 to 9.0,
including Salmonella enterica serovars Typhimurium
growing in low-acid foods, however, salad at pH 5.5 to
and Enteritidis, which can cause paratyphoid in infected
5.7 has been found unfavourable for growth. The lowest
animals. This group colonizes the alimentary tract of food
a for growth varies with the food but is about 0.93 to
animals, and leads to gastrointestinal disease in a broad
0.95. The species and strains of Salmonella differ too,
range of hosts, including humans. Group 2 comprises a
in heat resistance and effect of environmental factors on
small number of serovars that cause systemic typhoid-like
growth (Frazier and Westhoff, 2003) . Several years ago,
disease in a restricted range of host species. A wide variety
hurdle technology was developed as a new concept for the
of domestic and wild animals viz. cattle, swine, sheep,
realization of safe, stable, nutritious, tasty, and economical
goat, horses, and fowl could be the reservoirs of zoonotic
foods (McMeekin et al ., 2000). Several environmental
Salmonellae. Practically, any food of animal origin can be
factors such as temperature, pH, water activity (aw),
a source of infection for man. The most common vehicles
atmosphere, and presence or absence of preservatives