agar and lauric-acid

Changes in the size of populations of different groups of bacteria composing the normal flora of processed broiler skin were examined after each of five consecutive washings in mixtures of potassium hydroxide (KOH) and lauric acid (LA). Portions of skin from commercially processed broiler carcasses were washed in distilled water (control) or in mixtures of 0.25% KOH-0.5% LA or 0.5% KOH-1% LA by using a stomacher laboratory blender to agitate the skin in the solutions. After each wash, skin was transferred to fresh solutions, and washing was repeated to provide samples washed one to five times in each solution. Bacteria in rinsates of the washed skin were enumerated on plate count (PC) agar, Staphylococcus (STA) agar, Levine eosin methylene blue (EMB) agar, lactic acid bacteria (LAB) agar, and Perfringens (PER) agar with TSC supplement. Selected isolates recovered on each medium were identified. Overall, no significant differences were observed in numbers of bacteria recovered on PC, STA, or EMB agars from skin after repeated washing in water, but there were significant reductions in the number of bacteria recovered on LAB and PER agars. Repeated washing of skin in 0.25% KOH-0.5% LA or 0.5% KOH-1% LA generally produced significant reductions in the number of bacteria recovered on all media. Furthermore, no bacteria were recovered on PER agar from skin washed five times in 0.25% KOH-0.5% LA. Likewise, no bacteria were recovered on EMB or LAB agars from skin washed three or more times in 0.5% KOH-1% LA or on PER agar from skin washed four or five times in this solution. Staphylococcus spp. were identified as the skin isolates with the highest degree of resistance to the bactericidal activity of KOH-LA. Findings indicate that although bacteria may be continually shed from poultry skin after repeated washings, bactericidal surfactants can be used to remove and kill several types of bacteria found on the surface of the skin of processed broilers.

Topics: Agar; Animals; Anti-Bacterial Agents; Bacteria; Chickens; Colony Count, Microbial; Consumer Product Safety; Dose-Response Relationship, Drug; Drug Combinations; Food Contamination; Food Microbiology; Food-Processing Industry; Humans; Hydroxides; Lauric Acids; Potassium Compounds; Skin

The aim of this study was to add to the range of charged surfactants that can be used to form catanionic aggregates with oppositely charged surface active drug substances; and to apply these aggregates to prolong drug release from gels. The surfactants used in this study, lauric and capric acids are of natural origin-unlike traditionally used, synthetic, surfactants. The mixtures of drug substances and oppositely charged surfactants were studied visually and with cryogenic transmission electron microscopy. Drug release from gels was studied with a modified USP paddle method. This study shows that lauric and capric acids are as, or even more, active in forming catanionic aggregates than traditionally used surfactants such as sodium dodecyl sulfate. It is shown that the length of the hydrophobic part of the surfactant plays an important role in the formation of pharmaceutically interesting catanionic aggregates. As seen in previous studies, using catanionic vesicles prolongs the drug release from gels and decreases the apparent diffusion coefficient by a factor of 10-50, compared to a gel containing only drug substance.

Topics: Agar; Cations; Chemistry, Pharmaceutical; Cryoelectron Microscopy; Decanoic Acids; Delayed-Action Preparations; Diffusion; Gels; Lauric Acids; Microscopy, Electron, Transmission; Sodium Dodecyl Sulfate; Surface Properties; Surface-Active Agents; Technology, Pharmaceutical; Tetracaine