Study of Intermediate Products from Micronized Coal Reburning which used Organic Acid Salt as Accelerant

Two commercially available organic acid salts, potassium lactate (PURASAL HiPure P) and a potassium lactate–sodium diacetate blend (PURASAL Opti.Form PD 4), were assessed as potential inhibitors of Listeria monocytogenes growth in modified atmosphere packaged (MAP) sliced ham in challenge studies. The influence of the initial inoculation level of L. monocytogenes (101 or 103 CFU g−1) and storage temperature (4 or 8°C) was also examined. The addition of either organic acid salt to MAP sliced ham strongly inhibited the growth of L. monocytogenes during the normal shelf life of the product under ideal refrigeration conditions (4°C) and even under abusive temperature conditions (i.e., 8°C). During the challenge studies and in the absence of either organic acid salt, L. monocytogenes numbers increased by 1,000-fold after 20 days at 8°C and 10-fold after 42 days at 4°C. Both organic acid salt treatments were found to be listeriostatic rather than listericidal. The addition of either organic acid salt to the MAP ham also reduced the growth of indigenous microflora, i.e., aerobic microflora and lactic acid bacteria. The influence of these compounds on the risk of listeriosis in relation to product shelf life is discussed.

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Immediate Reduction of Salmonella enterica Serotype Typhimurium Viability via Membrane Destabilization following Exposure to Multiple-Hurdle Treatments with Heated, Acidified Organic Acid Salt Solutions

Applied and Environmental Microbiology ◽

10.1128/aem.02839-10 ◽

2011 ◽

Vol 77 (11) ◽

pp. 3765-3772 ◽

Cited By ~ 25

Author(s):

S. R. Milillo ◽

E. Martin ◽

A. Muthaiyan ◽

S. C. Ricke

Keyword(s):

Cell Membrane ◽

Organic Acid ◽

Salmonella Enterica ◽

Sodium Acetate ◽

Specific Response ◽

Ion Leakage ◽

Acid Salt ◽

Salt Solutions ◽

Sodium Propionate ◽

Content Type

ABSTRACTThe antimicrobial activity of organic acids in combination with nonchemical treatments was evaluated for inactivation ofSalmonella entericaserotype Typhimurium within 1 min. It was observed that the effectiveness of the multiple-hurdle treatments was temperature (P≤ 0.05) and pH (P≤ 0.05) dependent and corresponded to the degree of organic acid lipophilicity (sodium acetate being least effective and sodium propionate being the most effective). This led to the hypothesis that the loss in viability was due at least in part to cell membrane disruption. Evaluation of osmotic response, potassium ion leakage, and transmission electron micrographs confirmed treatment effects on the cell membrane. Interestingly, all treatments, even those with no effect on viability, such as with sodium acetate, resulted in measurable cellular stress. Microarray experiments explored the specific response ofS. Typhimurium to sodium acetate and sodium propionate, the most similar of the tested treatments in terms of pKaand ionic strength, and found little difference in the changes in gene expression following exposure to either, despite their very different effects on viability. Taken together, the results reported support our hypothesis that treatment with heated, acidified, organic acid salt solutions for 1 min causes loss ofS. Typhimurium viability at least in part by membrane damage and that the degree of effectiveness can be correlated with lipophilicity of the organic acid. Overall, the data presented here indicate that a combined thermal, acidified sodium propionate treatment can provide an effective antimicrobial treatment againstSalmonella.

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