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janlu:
Gastric juice has a pH of 3-4. You can start with a dilute solution of acetic acid (vinegar). You can measure pH with special paper strips available from your school chemistry department or chemical supply houses.
Matthew Mulanax
Simulated Gastric Fluid
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jlanlru:
This is a paper citaton showing how to make simulated gastric jucie.
You canse hydrochloric acid at pH 3 or som but you must be extremely careful. Hydrochloric acid is very hazardous - burns human tissue to a crisp - no joke.
I suggest using acetic acid or citric cid for your initial tests.
Look at the scienc fair project that was listed yesterday.
Inactivation of Escherichia coli O157:H7 in Simulated Human Gastric Fluid
Mark L. Tamplin*
Eastern Regional Research Center, Microbial Food Safety Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Wyndmoor, Pennsylvania
Received May 17, 2004; Accepted August 30, 2004.
Preparation of simulated gastric fluid. The SGF was produced following the formulation reported by Beumer et al. (6). The following constituents were mixed in deionized water: proteose peptone (8.3 g/liter; Difco), d-glucose (3.5 g/liter; Mallinckrodt, Paris, Ky.), NaCl (2.05 g/liter; Mallinckrodt), KH2PO4 (0.6 g/liter; Sigma Chemical Company, St. Louis, Mo.), CaCl2 (0.11 g/liter; Fisher, Fair Lawn, N.J.), KCl (0.37 g/liter; Sigma), porcine bile (0.05 g/liter; Sigma), lysozyme (0.10 g/liter; Sigma), and pepsin (0.0133 g/liter; Sigma). The SGF was adjusted to pH 1.5 with HCl, filter sterilized through a 0.22-μm-pore-size membrane, and stored at 4°C until use. Previous experiments showed that storage of the SGF at 4°C for up to 7 days did not result in significant changes in bactericidal properties (data not shown).
Matt Mulanax
This is a paper citaton showing how to make simulated gastric jucie.
You canse hydrochloric acid at pH 3 or som but you must be extremely careful. Hydrochloric acid is very hazardous - burns human tissue to a crisp - no joke.
I suggest using acetic acid or citric cid for your initial tests.
Look at the scienc fair project that was listed yesterday.
Inactivation of Escherichia coli O157:H7 in Simulated Human Gastric Fluid
Mark L. Tamplin*
Eastern Regional Research Center, Microbial Food Safety Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Wyndmoor, Pennsylvania
Received May 17, 2004; Accepted August 30, 2004.
Preparation of simulated gastric fluid. The SGF was produced following the formulation reported by Beumer et al. (6). The following constituents were mixed in deionized water: proteose peptone (8.3 g/liter; Difco), d-glucose (3.5 g/liter; Mallinckrodt, Paris, Ky.), NaCl (2.05 g/liter; Mallinckrodt), KH2PO4 (0.6 g/liter; Sigma Chemical Company, St. Louis, Mo.), CaCl2 (0.11 g/liter; Fisher, Fair Lawn, N.J.), KCl (0.37 g/liter; Sigma), porcine bile (0.05 g/liter; Sigma), lysozyme (0.10 g/liter; Sigma), and pepsin (0.0133 g/liter; Sigma). The SGF was adjusted to pH 1.5 with HCl, filter sterilized through a 0.22-μm-pore-size membrane, and stored at 4°C until use. Previous experiments showed that storage of the SGF at 4°C for up to 7 days did not result in significant changes in bactericidal properties (data not shown).
Matt Mulanax