More questions

You do not need a Google Blog account to read the blog. Answers to your questions:

1. Is Pseudomonas species salt-tolerant and can stand food w/ 7% salt w/v?

A:Many Pseudomonas spp are salt-tolrant and can grow on food at 7% salt w/v.

2. What is the pH range for Pseudomonas species to grow? Can it grow in food w/

pH 5.2?

A: Pseudomonas spp are highly diversified in many properties. They are not acid tolerant and likes to grow around neutral pH. They probably cannot grow in food at pH5.2.

3. As Listeria monocytogenes grows at pH>5.5,then it must be impossible to grow

in food w/ pH 4.8??

A: pH limits are influenced by many factors including the type of acids in the food. Where did you get the limit of pH>5.5? Your statement does not indicate that pH5.5 is the limit. Some reports showed that L.m. can grow at pH as low as 4.25.

4. Is Escherichia coli 0157 H7 salt-tolerant and can stand food w/ 7% salt w/v?

A: O157:H7 is not salt-tolerant. It would grow very poorly in food at 7% salt w/v. Some reports showed that it cannot grow at all at salt content above 8.4%.

5. What is the pH range for Saccharomyces cerevisiae to grow?

A: Saccharomyces cerevisiaw grows around neutral and slightly acidic pH. It is not usually characterized by their pH range. It is a fungus and can tolerate strong acids better than weak organic acids.

-----Original Message-----
From: wwwwwwwwwwwwwwwwwwww
Sent: Monday, May 07, 2012 12:27 AM
To: b097709@mailserv.cuhk.edu.hk
Subject: Questions on FNSC4180 Food Microbiology

Dear Prof. Kwan,

  I would like to ask you some questions on the course via e-mail as I don't

have a google blog account.Thank you very much!!!

1. Is Pseudomonas species salt-tolerant and can stand food w/ 7% salt w/v?

2. What is the pH range for Pseudomonas species to grow? Can it grow in food w/

pH 5.2?

3. As Listeria monocytogenes grows at pH>5.5,then it must be impossible to grow

in food w/ pH 4.8??

4. Is Escherichia coli 0157 H7 salt-tolerant and can stand food w/ 7% salt w/v?

5. What is the pH range for Saccharomyces cerevisiae to grow?