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Food Preservation and the Antimicrobial Activity of Australian Native Plants
Published in Yasmina Sultanbawa, Fazal Sultanbawa, Australian Native Plants, 2017
Two other sauces were prepared with traditional chemical preservatives in place of the native plant extracts. Potassium sorbate (0.665% w/w) and sodium benzoate (0.059% w/w) were used at permitted levels as given in Standard 1.3.1 of the Australia New Zealand Food Standard Code. The base mix for the sauces consisted of xanthan gum, starch and water and was taken as the control. The sauces were challenged with the following microorganisms: S. aureus and E. coli (105 cfu/g), Saccharomyces cerevisiae (105 cfu/g) and Aspergillus niger (105 cfu/g) and stored at 4°C and 25°C for 30 days. The fish fillets were dipped in oregano essential oil and then coated with sauces A or B, placed in modified atmosphere packaging and stored at 4°C for 12 days.
Need of Other Elements
Published in Flavia Meyer, Zbigniew Szygula, Boguslaw Wilk, Fluid Balance, Hydration, and Athletic Performance, 2016
Artificial preservatives are often included in bottled, ready-to-drink beverages to avoid spoilage and therefore extend the shelf life of the product. They act mainly by preventing growth of bacteria, molds, fungi, and yeasts, and they represent a less costly alternative to processes such as pasteurization combined with hot or cold filling industrial procedures. There are, however, two disadvantages of artificial preservatives. First, artificial ingredients are not well accepted in many cultures, particularly in association with a beverage used for hydration, as the drink is meant to be ingested in large volumes, and it should share the healthy image associated with exercise. Second, some preservatives such as sodium benzoate and potassium sorbate may negatively modify the palatability characteristics of drinks, which is undesirable as it may decrease voluntary intake (Passe et al. 2004). Specifically, the presence of sodium benzoate at 0.03% has been reported to reduce voluntary fluid intake by 10.8% during 30 min of moderate intensity exercise in thermoneutral conditions (Passe et al. 1997), even though it had no measurable effects on sensory variables.
Preservatives and Preservation
Published in Philip A. Geis, Cosmetic Microbiology, 2020
Organic acids. These are some of the oldest cosmetic preservatives and currently include benzoic, sorbic, and dehydroacetic acids. Mode of action is generally attributed to factors such as disruption of proton motive force and acidification of cytoplasm (63). As antimicrobial activity is associated with the protonated molecule, these are primarily effective at pH less than or approximating their pKas (45,63). Used at concentrations up to 8000 ppm, they are primarily effective against Gram-positive bacteria and fungi (45). However, benzoic acid has been used as an effective co-preservative versus Gram-negative bacteria at near-neutral pH in some rinse-off, surfactant-based cosmetics. Foster et al. recently reported the combination establishes a significant increase in apparent pKa through interaction with surfactant micelles (64). This phenomenon with resulting greater efficacy challenges the long-held industry assumption that the pKa of benzoic acid remains at a constant 4.2 in all aqueous systems. Again, in surfactant-based products, benzoic acid with benzyl alcohol can establish synergistic efficacy against Gram-negative bacteria. Smauqi et al. (65) reported unexpected efficacy of organic acid combinations in olive oil emulsion using a modified, novel preservative effectiveness test. However, to address general Gram-negative bacterial risk, organic acids are routinely combined with formaldehyde releasers, phenoxyethanol, or MCIT (24). Combination with other preservatives is also important as organic acids can serve as substrate for microbial metabolism (45,66,67). Organic acid preservatives are routinely formulated as their respective sodium (benzoate and dehydroacetic) or potassium (sorbate) salts as these are much more soluble at the pH of a conventional cosmetic product formulation (45). Benzoic acid, and perhaps other organic acids, may be removed from aqueous solution by cyclodextrin and absorption by clays such as montmorillinote and some flexible tubing materials (68–70). Sorbic acid can undergo degradation with some amino acids, glycerol, and some salts (70). Further care should be taken with sorbic acid as it is prone to auto-oxidation especially at higher (less acidic) pH (71), a phenomenon accelerated by EDTA (ethylene diamine tetraacetic acid), a commonly used chealtor (72). Dehydroacetic acid should not be combined with formaldehyde releasers or MCIT due to reaction with free formaldehyde of the former and the stabilizing magnesium ion of the latter (73,74).
Stability study of a clonidine oral solution in a novel vehicle designed for pediatric patients
Published in Pharmaceutical Development and Technology, 2018
Arnaud Potier, Julien Voyat, Alain Nicolas
Inorpha® is a suitable vehicle for compounding hospital preparation. We demonstrated that clonidine hydrochloride dissolved in Inorpha® is stable at 5 ± 3 °C for 60 days unopened and for 30 days of daily opening after a pre-storage period of 30 days (‘in-use’ study). The color, clarity, osmolality and pH remained within the specifications throughout the course of the study. The concentration of potassium sorbate remained within the specifications (90.0–110.0%) all over the study guaranteeing the microbiological quality of the preparation. However, the results obtained at 25 ± 2 °C do not allow to assign a sufficient shelf-life for a 30-day therapeutic schedule. The latter finding is consistent with the monograph on clonidine hydrochloride oral liquid published in the Handbook of Extemporaneous Preparation (Clonidine hydrochloride, 2010) which recommends a shelf-life of 28 days under refrigerated conditions for a 10-µg/mL solution stored in amber glass.