Showing papers on "Sodium propionate published in 2005"

Effect of Immersion Solutions Containing Enterocin AS-48 on Listeria monocytogenes in Vegetable Foods

Abstract: The effect of immersion solutions containing enterocin AS-48 alone or in combination with chemical preservatives on survival and proliferation of Listeria monocytogenes CECT 4032 inoculated on fresh alfalfa sprouts, soybean sprouts, and green asparagus was tested. Immersion treatments (5 min at room temperature) with AS-48 solutions (25 μg/ml) reduced listeria counts of artificially contaminated alfalfa and soybean sprouts by approximately 2.0 to 2.4 log CFU/g compared to a control immersion treatment in distilled water. The same bacteriocin immersion treatment applied on green asparagus had a very limited effect. During storage of vegetable samples treated with immersion solutions of 12.5 and 25 μg of AS-48/ml, viable listeria counts were reduced below detection limits at days 1 to 7 for alfalfa and soybean sprouts at 6 and 15°C, as well as green asparagus at 15°C. Only a limited inhibition of listeria proliferation was detected during storage of bacteriocin-treated alfalfa sprouts and green asparagus at 22°C. Treatment with solutions containing AS-48 plus lactic acid, sodium lactate, sodium nitrite, sodium nitrate, trisodium phosphate, trisodium trimetaphosphate, sodium thiosulphate, n-propyl p-hydroxybenzoate, p-hydoxybenzoic acid methyl ester, hexadecylpyridinium chloride, peracetic acid, or sodium hypochlorite reduced viable counts of listeria below detection limits (by approximately 2.6 to 2.7 log CFU/g) upon application of the immersion treatment and/or further storage for 24 h, depending of the chemical preservative concentration. Significant increases of antimicrobial activity were also detected for AS-48 plus potassium permanganate and in some combinations with acetic acid, citric acid, sodium propionate, and potassium sorbate.

Fermentation patterns of small-bale silage and haylage produced as a feed for horses

Abstract: The fermentation quality of small-bale silage and haylage for feeding to horses in Sweden, and using a conventional high-density hay baler, was investigated in two experiments. Treatments studied were use of additives (inoculants containing lactic acid bacteria and a chemical additive consisting of hexamethylenetetramine, sodium nitrate, sodium benzoate and sodium propionate), the influence of dry-matter (DM) content of wilted herbage and the effect of number of stretch film layers on fermentation pattern and aerobic stability. All silages and haylages were made from predominantly Timothy swards and were well fermented as indicated by low levels of ammonia and butyric acid. Values of pH were higher and concentrations of organic acids were lower in haylages than in the silages. This was not considered to be indicative of a poor fermentation in the haylage but of a restricted fermentation due to the high DM content of the herbage. The additives enhanced aerobic storage stability because of inhibition of mould growth. The only statistically significant effect of varying the number of stretch film layers was a higher content of CO2 inside the bales when ten layers of stretch film were applied compared with six layers.

Possibilities to improve silage conservation

Abstract: The objective of this thesis was to investigate factors to improve the silage quality of different types of forage crops. The focus was on the influence of crop maturity, silage additives and laceration on the quality of whole-crop cereals silages. The ensilability of whole-crop cereals was highly dependent upon the stage of maturity. An important factor related to the stage of maturity and influencing the ensilability of whole-crop cereals seems to be the concentration of WSC in the fresh forage. Ensiling at the milk stage was found to be a more suitable time to harvest whole-crop cereals since there is a sufficient concentration of water soluble carbohydrates (WSC) that provides the conditions for lactic acid bacteria (LAB) to rapidly dominate the silage microflora and produce enough acids to reduce pH thereby giving a better protection of the silage against the spoilage microflora. The low WSC concentration of whole-crop cereals at dough stage seems to restrain good fermentation. However, silages harvested at the milk stage still appear to have a low aerobic stability. Precision chopping had variable affects on silage fermentation and showed that laceration is not a guarantee of a good silage quality of whole-crop cereals. At the milk stage, precision chopping improved the silage fermentation, whereas the dough-stage silages tended to give clostridial fermentation resulting in poor quality and high DM losses. Precision chopping promoted a higher silage density at the milk stage and resulted in reduced DM losses at the dough stage. Application of silage additives was the most important factor in improving silage quality. A mixture of sodium benzoate, sodium propionate, hexamine and sodium nitrite seems to be the most suitable additive to secure the silage quality and improve the aerobic stability in whole-crop cereals as well as in moderate and highly -wilted clover-grass forages. No remaining toxic residues of the nitrite concentration were found in the silages. A similar influence on the ensiling process is found when using the combination of sodium benzoate, sodium propionate and propionic acid. The results of mixtures of formic acid and propionic acid were closely related to the chop length of the forage. These additive combinations seem to improve the silage quality and storage stability in precision-chopped silages at both maturities, while the quality of long-cut treated silages often appeared to be low. The variable efficiency of inoculation of whole crop cereals with LAB seems to be associated with types and numbers of epiphytic bacteria in the herbage. The inoculation of homofermentative LAB successfully reduced pH of both precision-chopped and long cut-silages but abundant production of lactic acid did not secure the aerobic stability of these

The characteristic of the phosphorus anaerobic release from activated sludge in different substrates with MDAT-IAT process

Abstract: The characteristic of the phosphorus release from activated sludge under anaerobic condition in different substrates with Modified Demanded Aeration Tank-Intermittent Aeration Tank(MDAT-IAT) process was studied. The amounts of phosphorus release from activated sludge were 1.58?(mg·L~(-1)), 3.55?(mg·L~(-1)), 3.04?(mg·L~(-1)) and 1.86?(mg·L~(-1)), and the rates of the phosphorus release were 0.02?(mg·L~(-1)·min~(-1)), 0.05?(mg·L~(-1)·min~(-1)), 0.15?(mg·L~(-1)·min~(-1)) and 0.06?(mg·L~(-1)·min~(-1)) with glucose, sodium format, sodium acetate and sodium propionate as a sole carbon source, respectively. The phosphorus release from activated sludge under anaerobic condition in the mixture of the same four substrates was also studied. The results indicated that the amount and rate of phosphorus release in the mixed substrates were much greater than those in the four sole substrates, reaching 8.51?(mg·L~(-1)) and 0.31?(mg·L~(-1)·min~(-1)), respectively.