Organic acids concentrations

Organic acids concentrated in deposits and caused most attack. 

Table X. Percent germination and root hypocotyl length of birdsfoot trefoil as affected by organic acids (concentration 10 1n and pH 4) ...

A large component of supernatant BOD5 is comprised of organic acids and similar correlations exist between total organic acids concentration (TOA) and odour offensiveness. The correlation is not as good as that of soluble BOD5 but the estimation of TOA is a much quicker procedure. 

Potential gas-phase organic acid concentrations [P (/tg/m )] were then calculated for two assumed values of cloud liquid water content (L, g H20/m air) using the equation... 

Table II. Values Used in Calculating Equilibrium and Potential Gas-Phase Organic Acid Concentrations...

With formic and carbonic acid as potential chain transfer agents, termination would involve the proton of the undissociated acid, but HCOO" and HOCOO were very poor nucleophiles and did not reinitiate the polymerization. This amounted to an overall inhibition or retardation of the formaldehyde polymerization. 2 mole % of COj inhibited formaldehyde polymerization completely [29], as did other inorganic or organic acids which gave poorly nucleophilic anions. Higher organic acid concentration may cause cationic polymerization. 

Figure I Organic acids concentration in the liquid phases (in 100 g-modcl garbage)...

Increased effectiveness of organic acids may be achieved when used in lower concentrations, but in combination with additional inhibitors. For example, combining nisin with reduced organic acid concentrations may decrease potential flavor flaws in meat products (Samelis et al., 2005). Citric and ascorbic acids, in combination, are effective in inhibiting growth and toxin production of C. botulinum type B in vacuum-packed foodstuffs (Barbosa-Canovas et al., 2003 Samelis et al., 2005). In other studies, a combination of equal amounts of ascorbic acid and citric acid did not have additional benefits, compared with using ascorbic acid alone (Mancini et al., 2007). 

Treated carcasses are known to possess pH values ranging from 3.3-5.8 (Kanellos and Burriel, 2005 Mehyar et al., 2005 Del Rfo et al., 2007). The pH may be influenced by different factors, such as (1) the type of organic acid, (2) treatment time, (3) organic acid concentration, and (4) combinations with other decontamination techniques (Del Rfo et al., 2007 Alvarez-Ordonez et al., 2009). 

Le Marc, Y., Huchet, V., Bourgeois, C.M., Guyonnet, J.P., Mafart, P., and Thuault, D. 2002. Modeling the growth kinetics of Listeria as a function of temperature, pH and organic acid concentration. International Journal of Food Microbiology 73 219-237. 

Stopforth, J.D., Samelis, J., Sofos, J.N., Kendall, P.A., and Smith, G.C. 2003. Influence of organic acid concentration on survival of Listeria monocytogenes and Escherichia coli 0157 H7 in beef carcass wash water and on model equipment surfaces. Food Microbiology 20 651-660. 

We have operated an auxostat by monitoring organic acid concentration and controlling by dilution with fresh feed. Feed is slowed when below the setpoint to allow the organisms to produce more acids to restore their concentration. A rise in concentration causes the feed pump to speed up to dilute the acids. This was the status of our research when the project was put on hold while a search was initiated to find a new research assistant who could handle the engineering, biochemistry and microbiology of this complex system. 

Organic Acid Concentration (mM) Price ( /lb mol) Relative Cost... 

Variations in the organic acid concentrations of diverse waters with respect to temperature suggest a strong thermal influence (Fig. 1). In Cenozoic age reservoirs maximum organic acid... 

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