Food or edible material: processes – compositions – and products – Inhibiting chemical or physical change of food by contact... – Biocidal or disinfecting chemical agent
Reexamination Certificate
1999-02-26
2001-04-17
Pratt, Helen (Department: 1761)
Food or edible material: processes, compositions, and products
Inhibiting chemical or physical change of food by contact...
Biocidal or disinfecting chemical agent
C426S052000, C426S056000, C426S321000, C426S335000, C426S532000, C426S615000, C426S654000, C426S655000
Reexamination Certificate
active
06217925
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a general method for isolation and growth of nitrite-resistant bacteria with a high level of inducible nitrate reductase activity. In particular, the present invention relates to a method of isolation and growth of bacteria with a high level of inducible nitrate reductase activity using Chinese cabbage and celery extracts as a source of the bacteria and media.
The present invention also relates to a general method of inhibiting bacterial growth in foods by adding nitrate-rich vegetable extracts. More specifically, the present invention demonstrates an anti-bacterial effect of Chinese cabbage and celery extracts on beef during storage.
2. Description of Related Art
Sodium nitrate and nitrite are added to meat as preservatives to ward off bacteria. These compounds are also responsible for a bright-red color of cured meat (Committee on nitrite and alternative curing agents in food, national Academy of Sciences, Chapter 3, 1981). Vegetables such as celery, spinach, beets, turnip greens, radishes and lettuce have a high nitrate content (Committee on nitrite and alternative curing agents in food, national Academy of Sciences, Chapter 5, 1981). As a result, nitrate consumed by U.S. residents is primarily through vegetables. However, the main source of nitrite in the U.S. is cured meats (Committee on nitrite and alternative curing agents in food, national Academy of Sciences, Chapter 5, 1981; White, 1975).
In mammalian cells, nitric oxide synthase catalyzes formation of nitric oxide from L-arginine. Nitric oxide plays a significant role in signal transduction and cell to cell communication. Nitric oxide release can be assayed by measuring its stable degradation products, nitrite and nitrate (Schmidt, 1995).
The most commonly used method for analysis of nitrite is a colorimetric method using the Griess reaction (Committee on nitrite and alternative curing agents in food, national Academy of Sciences, Chapter 5, 1981; Schmidt, 1995). Nitrate is determined by measurement of nitrite by the Griess reaction after reduction of nitrate to nitrite (Committee on nitrite and alternative curing agents in food, national Academy of Sciences, Chapter 5, 1981; Schmidt, 1995). Nitrate is reduced to nitrite by passing the reaction mixture through a column packed with cadmium shavings or by adding granulated cadmium in the mixture (Committee on nitrite and alternative curing agents in food, national Academy of Sciences, Chapter 5, 1981; Vodovotz, 1996).
Recently, nitrate was enzymatically reduced to nitrite by incubation with nitrate reductase. Nitrate reductase has been studied in bacteria, fungus and plants. Thus far three different kinds of nitrate reductases have been found. Assimilatory nitrate reductase converts nitrate to ammonia, vianitrite, which is assimilated to nitrogen metabolism.
Ammonia, the end product of the pathway inhibits nitrate reductase activity and oxygen does not have any effect on the nitrate reductase activity (Kubo, et al., 1988; Hyde et al., 1990). A membrane-bound, respiratory (dissimilatory) nitrate reductase converts nitrate to nitrite (Carlson, et al. 1982) and then the formed nitrite is converted to nitric oxide and nitrous oxide by respiratory nitrite reductase (Smith, et al. 1992). This pathway, which produces ATP from ADP using nitrate in anaerobic condition, is insensitive with ammonia.
Recently, the third nitrate reductase, periplasmic nitrate reductase, has been found. Contrary to the other nitrate reductases, the periplasmic nitrate is not encoded on the chromosome, but by the megaplasmid and the gene products with a signal peptide are found in the periplasm (Bursakov, et al. 1997; Siddiqui, et al. 1993; Carter, et al. 1995). This nitrate reductase may be involved in cellular redox balance.
A few commercially available nitrate reductases are nitrate reductase which are obtained from
E. coli
(Worthington Biochemical Co. and Sigma Co, Aspergillus (Boehringer-Mannheim), and corn (The Nitrate Elimination Co.).
The significance of the presence of nitrite and nitrate in meat relates to health concerns. Adding nitrite and nitrate to meat became a health problem because sometimes nitrite reacts with the amines in meat. This reaction forms a chemical, nitrosamines, that is found to cause cancer in laboratory animals (Graham, 1980). To avoid the health problem caused by this nitrosamine formation, some meat products contain BHA and BHT, preservatives of another kind. However, neither of these preservatives are naturally occurring.
It would therefore be useful to develop a method for the isolation and growth of nitrite released in bacteria with high nitrate reductase activity. Additionally, it would be useful to develop a method for the retardation of bacterial growth in foods using plant extracts.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a method for retarding bacterial growth in foods by adding plant extracts. Also provided is a bacterial growth inhibitor for foods containing a plant extract. A method for isolating nitrate-resistant bacteria with nitrate reductase activity by growing nitrate-resistant bacterial and nitrate rich media is also provided. Also provided is a method of measurement utilizing nitrate-resistant bacteria with high nitrate reductase activity.
REFERENCES:
patent: 3374099 (1968-03-01), Bell et al.
patent: 849358A2 (1998-06-01), None
Committee on Nitrite and Alternative Curing Agents in Food, National Academy of Sciences (1981) Chapter 3. The Utility of Nitrate and Nitrite Added to Foods in The Health Effects of Nitrate, Nitrite, and N-nitroso Compounds, Washington, DC National Academy Press.
Committee on Nitrite and Alternative Curing Agents in Food, National Academy of Sciences (1981) Chapter 5, Nitrate, Nitrite, and Nitrogen Oxides: Environmental Distribution and Exposure of Humans in The Health Effects of Nitrate, Nitrite, and N-Nitroso Compounds, Washington, DC National Academy Press.
White, Jr., J.W. (1975) Relative Significance of Dietrary Sources of Nitrate and Nitrite. J. Agric. Food Chem. 23, 886-891.
Schmidt, H. H. H. (1995) Determination of Nitric Oxide via Measurement of Nitrite and Nitrate in Culture Media. Biochemica 2,77.
Vodovotz, Y. (1996) Modified Microassay for Serum Nitrite and Nitrate. BioTechniqaues 20, 390-394.
Kubo, Y., Ogura, N. and Nakagawa, H. (1988) Limit Proteolysis of the Nitrate Reductase From Spinach Leaves. J. Biol. Chem. 263, 19684-19689.
Hyde, G. and Campbell, W., (1990) High-level expression on Escherichia coli of the Catalytically Active Flavin Domain of Corn Leaf NADH:nitrate reductase and its comparison to human NADH:cytochrome b5 Reductase. Biochem. Biophys. Res. Commun. 168, 1285-1291.
Carlson, C.A., Ferguson, L.P. and Ingraham, J.L. (1982) Properties of Dissimilatory Nitrate Reductase Purified from the Denitrifier Pseudomonas Aeruginosa. J. Bacteriol. 151, 162-171.
Smith, G.B. and Tiedje, J.M. (1992) Isolation and Characterization of a Nitrite Reductase Gene and Its Use as a Probe for Denitrifying Bacteria. Appl. Environ. Microbiol. 58, 376-384.
Bursakov, S.A., Carneiro, C., Almendra, M.J., Duarte, R.O., Caldeira, J., Moura, I. and Moura, J.J. G. (1997) Enzymatic Properties and Effect of Ionic Strength on Periplasmic Nitrate Reductase (NAP) From Desulfovibrio Desulfuricans ATCC 27774. Biochem. Biophys. Res. Commun. 239, 816-822.
Siddiqui, R.A., Warnecke-Eberz, U. Hengsberger, A., Schneider, B., Kostka, S. and Friedrich, B. (1993) Structure and Function of a Periplasmic Nitrate Reductase in Alcaligenes Eutrophus H16. J. Bacteriol. 175, 5867-5876.
Carter, J.P., Richardson, D.J. and Spiro, S. (1995) Isolation and Characterisation of a Strain o fPseudomonas Putida That Can Express a Periplasmic Nitrate Reductase. Arch. Microbiol. 163, 159-166.
Enoch, H.G., and Lester, R.L., The Purification and Properties of Formate Dehydrogenase and Nitrate Reductase fromEscherichia Coli. J. Biol. Chem. 250, 6693, 1975.
Fox, B.A. and Cameron, A.G. Food Spoilage and Preservation. In Food Science, Nutrit
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Pratt Helen
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