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The sorbate content of commercial yogurt samples is determined by reverse phase liquid chromatography following ion-pair extraction with tri-n-octylamine. Mean recoveries (70-88%), precision (1.1-3.3% RSD), and detection limit of the method are presented for sorbic acid, benzoic acid, and saccharin.
The effects on beef cattle growth performance and carcass characteristics of feeding silages produced by altered fermentations were determined. Alpha-amylase was added at 0 or .05% (wet basis) and sorbic acid was added at 0 or .10% (wet basis) to chopped whole corn plants before ensiling in a 2 x 2 factorial arrangement of treatments. For three successive years, 40 beef heifers (224 kg) were fed these silages for 80 d, finished on corn-and-cob meal (107 d) and slaughtered when backfat thickness over the 13th rib reached 12 mm. Silages treated with alpha-amylase had a slightly higher percentage of N-free extract (P less than .10). Silages treated with sorbic acid had lower percentages of ADFN (P less than .10). During the silage-feeding phase, heifers fed silages treated with alpha-amylase gained more (P less than .01) daily than heifers fed the other two silages (.84 vs .78 kg) and they were more efficient (P less than .01) in weight gain per unit of dry feed consumed (.149 vs .139 kg). During the finishing phase, heifers that previously had been fed the alpha-amylase-treated silage continued to have higher (P less than .05) ADG (.93 vs .87 kg), although all were fed the same diet during this period. Added sorbic acid had no effect on ADG in either period. The percentage of kidney fat in heifers on the alpha-amylase treatments was increased (P less than .02, 2.2 vs 2.0). The biological mechanisms associated with the beneficial results of alpha-amylase addition are not understood yet.
The effects of the initial pH and a "short pump" on the outgrowth of Clostridium sporogenes PA 3679 spores in comminuted cured pork were studied. Fresh ground pork was cured with salt, sugar, phosphate, ascorbate, and varying amounts of sodium nitrite and sorbic acid. The product was comminuted and inoculated with 1,000 spores of C. sporogenes per g. The meat was stuffed into 1-ounce (ca. 28.4-g) aluminum tubes, cooked to 58.5 degrees C, cooled, and incubated at 27 degrees C to observe for swells. Product cured with 0.2% sorbic acid in combination with 40 ppm sodium nitrite (40 microgram/g) had better clostridium inhibition than did product cured with 120 ppm nitrite within a pH range of 5.0 to 6.7. The sorbic acid-40 ppm nitrite combination also gave better clostridial protection than did the 120 ppm nitrite alone when reduced amounts of curing ingredients were present.
A simple differential-pulse polarographic method using a laboratory-built hanging mercury drop electrode as the working electrode was developed for the determination of sorbic acid in fruit juices and soft drinks. Sorbic acid was extracted from the samples with diethyl ether. After reduction of the ethereal solution to a small volume by direct evaporation, the residual ether was dissolved in the supporting electrolyte (25 ml of acetonitrile + 1 ml of 0.06 M acetic acid + 0.8 g of tetraethylammonium bromide). Peak current was measured at -1.7 V. The working range of the method, without dilution or pre-concentration of the samples, was from 4 to 229 p.p.m. for the original juice and drink samples. The validity of the method was confirmed by parallel determinations using the method of the Association of Official Analytical Chemists and by recovery tests on a large variety of juice samples. Satisfactory recoveries and agreement in results from the two methods were obtained. The recovery and precision (relative standard deviation) of the method were 97 +/- 4 and 100 +/- 3%, respectively, for blackcurrant juice for five determinations.
The minimum growth-inhibitory concentration of sorbic acid has been determined for Penicillium chrysogenum, Cladosporium cladosporioides and Ulocladium atrum at pH 4.1-7.6 by using a microculture technique. This technique had earlier been applied to bacteria and Candida albicans and gave very reliable minimum inhibitory values. This investigation has shown that it is suitable also for determination of mould growth. The minimum inhibitory concentrations of sorbic acid were at the tested pH levels 1-230 mmol l-1 for P. chrysogenum, 0.3-18.0 mmol l-1 for C. cladosporioides and 0.2-33.0 mmol l-1 for U. atrum. A mathematical model for combined inhibition by dissociated and undissociated acid, which gave a good description of the minimum inhibitory concentration data earlier obtained for bacteria and Candida albicans, was suitable also for moulds. Both dissociated and undissociated acid contributed to growth inhibition.
Effect of sorbic acid, an antimicrobial food preservative, on the cellular metabolism of Staphylococcus aureus was observed microcalorimetrically. The highly reproducible and characteristic thermograms of the microorganism were affected significantly by the preservative in a concentration dependent manner. Both the peak heat and total heat dissipation profiles were affected by 50% at the maximum permitted concentration (0.2%) for use in foods.
The minimum inhibitory concentration of sorbic acid has been determined for Bacillus subtilis, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans. The inhibition was shown to be due to both undissociated and dissociated acid, and the effect of each has been calculated in accordance with a proposed mathematical model. Although the inhibitory action of undissociated acid was 10-600 times greater than that of dissociated acid, the latter caused more than 50% of the growth inhibition at pH levels above 6 for most of the organisms tested.
Samples of (i) a control or of (ii) sodium nitrite-containing or (iii) sorbic acid-containing, mechanically deboned chicken meat frankfurter-type emulsions inoculated with Clostridium botulinum spores, or a combination of ii and iii, were temperature abuse at 27 degrees C. Spore germination and total microbial growth were followed and examined at specified times and until toxic samples were detected. The spores germinated within 3 days in both control and nitrite (20, 40 and 156 micrograms/g) treatments. Sorbic acid (0.2%) alone or in combination with nitrite (20, 40, and 156 micrograms/g) significantly (P less than 0.05) inhibited spore germinations. No significant germination was recorded until toxic samples were detected. A much longer incubation period was necessary for toxin to be formed in nitrite-sorbic acid combination treatments as contrasted with controls or nitrite and sorbic acid used individually. Total growth was not affected by the presence of nitrite, whereas sorbic acid appeared to depress it. Possible mechanisms explaining the effects of nitrite and sorbic acid on spore germination and growth are postulated.
When mice were fed on a diet containing 15% sorbic acid for a period up to 6 months, ether extracts of the intestinal contents of the mice were not mutagenic with Salmonella typhimurium TA98, but the acidic components obtained by fractionating the ether extracts, showed slightly mutagenic activity with S. typhimurium TA98, and they required the addition of liver 9,000 xg supernatant fraction for mutagenic activation. These results suggested that mutagens were gradually produced in the intestine and moved into the liver where they were metabolically activated. It is possible to presume that liver carcinoma might be attributable to the production of these mutagens.
The inhibitory effects of potassium sorbate on the bioenergetics, phenylalanine uptake, protein synthesis, and certain aspects of cell regulation were examined in putrefactive anaerobe 3679. Undissociated sorbic acid appeared to act as a protonophore by lowering the intracellular pH and dissipating the proton motive force of the membrane. Sorbate inhibited the uptake of phenylalanine, decreased the rate of protein synthesis, and altered patterns of phosphorylated nucleotide accumulation, resulting in increased intracellular concentrations of GTP, ppGpp, and an unidentified compound (possibly pppGpp). The addition of a noninhibitory amount of tetracycline released the inhibition of growth by sorbate. Based on these results, we concluded that the inhibition of putrefactive anaerobe 3679 by sorbate resulted from a stringent-type regulatory response induced by the protonophoric activity of sorbic acid.
Two thousand male, day-old Hubbard chicks were housed in 20 pens (13.5 m2) to evaluate the effects on performance and leg abnormalities of feeding 0, 200, 400, and 600 g/ton dietary sorbic acid during the starter, grower, and finisher periods. These levels of dietary sorbic acid had no significant effect on live body weight, feed conversion, mortality, or the incidence of leg abnormalities of these chicken broilers reared to roaster weight.
Competitive reverse transcription polymerase chain reaction (cRT-PCR) was used to quantify the toxin-encoding mRNA production of a Clostridium botulinum type E strain in media containing either sorbic acid or sodium nitrite. A 10-fold reduction in toxin mRNA production and a 25-fold reduction in the proportion of toxin mRNA to total RNA, was estimated when either 1 mg ml(-1) sorbic acid or 100 microg ml(-1) sodium nitrite were added to the medium at pH 7.0.
Thirty-two mould strains were isolated from Turkish-style black table olives. Four of these isolates were identified as Aspergillus ochraceus, two as A. niger, 16 as Penicillium clavigerum and 10 as P. expansum. Mould growth was evaluated on olives treated with 500 ppm sorbic acid, 1000 ppm methyl-eugenol and 1500 ppm çörtük spice (Echinophora sibthorpiana Guss.) essential oil. Olives inoculated with A. parasiticus NRRL 2999 and P. clavigerum were also examined. All samples were stored at 28 degrees C, 15 degrees C and 5 degrees C for 60 days. The lower the temperature, the more time it took the mould to initiate mycelium and spore development. Most inhibition of growth was obtained using sorbic acid in all cases and especially at low temperatures, followed by methyl-eugenol and essential oil. Decreased inhibition was observed in noninoculated olives. Inhibitory effect of used agents was higher in olives inoculated with P. clavigerum than in olives inoculated with A. parasiticus.
Three experiments were conducted with 288 weanling pigs to determine the effects of sorbic acid (SA) added to dry (DSG), high moisture (HMSG) or reconstituted (RSG) sorghum grain diets on gains and feed conversion. Dietary treatments for Exp. 1 were: DSG with and without .1% SA; HMSG with .1% SA and RSG with .1% SA. The DSG diets were fed ad libitum. The HMSG and RSG diets were mixed fresh from oxygen-limiting storage every 3 and 7 d and were also fed ad libitum. Pigs fed RSG diets consumed more feed than those fed HMSG diets (P less than .08). Performance was similar between pigs fed DSG diets without or with SA. Dietary treatments for Exp. 2 and 3 consisted of sorghum grains reconstituted to two moisture contents (MC), with additions of either 0, .05 or .1% SA. The diets were mixed fresh from oxygen-limiting storage every 7 d and fed ad libitum. In Exp. 2 and 3, pigs fed the higher MC diets were more efficient in feed conversion (P less than .03) than those fed the lower MC diets. In Exp. 3, a quadratic response (P less than .04) for average daily gain and average daily feed intake was observed for the main effect of SA. Feed efficiency improved (P less than .05) in a linear fashion as SA levels were increased in the diets. The results of these experiments indicate that weanling pigs may be fed HMSG or RSG without adverse effects on pig performance. Inconsistencies in pig response to SA were observed.(ABSTRACT TRUNCATED AT 250 WORDS)
An LC-MS method is described for the determination of urinary sorbic acid (SA), a common food additive, which allows to measure down to 4 microg/L of the compound. The method involves an acidic hydrolysis followed by solid-phase extraction. The method was applied to two volunteers who ingested SA and to 36 individuals with no dietary restriction. The results confirm that a little aliquot of ingested SA is found in urine also in humans. The significant correlation found between urinary levels of SA and trans,trans-muconic acid (MA) seems to indicate that the measurement of SA in urine could allow to estimate the amount of MA excreted following a dietary intake of SA and, consequently, to enhance the specificity of MA as a biomarker of benzene exposure. A point of clarification in future studies will be the actual chemical form of SA excreted, since our results clearly demonstrate that without hydrolysis only a very little amount of SA can be found even in subjects heavily exposed to SA.
The effect of three food preservatives, sorbic acid and methyl and butyl esters of p-hydroxybenzoic acid, on the protonmotive force in Escherichia coli membrane vesicles was investigated. Radioactive chemical probes were used to determine the two components of the protonmotive force: delta pH (pH difference) and delta psi (membrane potential). Both types of compound selectively eliminated delta pH across the membrane, while leaving delta psi much less disturbed indicating that transport inhibition by neutralization of the protonmotive force cannot be the only mechanism of action for the food preservatives tested.
A patient with contact urticaria with skin and respiratory symptoms was found to be sensitive to both sorbic acid and synthetic oil of cassia. The contact urticaria was only elicitable on intact skin of the face by open testing. The source of the patient's contactants was her shampoo and toothpaste.
The work presents some results from the evaluation of microbiological (total bacterial count, coliform bacteria, moulds and yeasts) and sensory (shape, odour, colour, taste, consistency, crust, soft inside, etc.) quality and of the aw value and pH during the 90-day storage (interval of 0, 30, 45, 60, 75 and 90 days) under laboratory conditions at 20 +/- 2 degrees C in eight types of the bakery croissant-type product with the nougat cream differing by the type of dough (brioche, croissant), aw value of the cream, and by the presence or absence of sorbic acid in the spirit spray applied onto the surface of products. The above-indicated parameters were examined also in the nougat cream samples (on the zero and 90th day of storage). The chosen quality parameters permitted the level of the durability influence of croissants depending on external (sorbic acid) as well as internal (recipe, aw) conditions to be estimated.