Abstract: Wood decay is addressed continuously within the wood industry through use and development of wood preservatives. The increasing awareness on the negative effects of many chemicals towards the environment is causing political restrictions in their use and creating more urgent need for research on green alternatives. This paper discusses some of the possible natural extracts for wood preserving applications and compares the analytical methods available for testing their behavior and efficiency against decay fungi. The results indicate that natural extracts have interesting chemical constituents that delay fungal growth but vary in efficiency depending on the chemical concentration and substrate used. Results also suggest that presence and redistribution of preservatives in wood during exposure trials can be assessed by spectral imaging methods although standardized methods are not available. This study concludes that, in addition to the many standard methods available, there is a need to develop new faster methods for screening potential preservative formulation while maintaining the comparability and relevance of results.
Abstract: Microbial degradation of foods is defined as a decrease of food safety due to microorganism activity. Organic acids, sulfur dioxide, sulfide, nitrate, nitrite, dimethyl dicarbonate and several preservative gases have been used as chemical preservatives in foods as well as natural preservatives which are indigenous in foods. It is determined that usage of herbal preservatives such as blueberry, dried grape, prune, garlic, mustard, spices inhibited several microorganisms. Moreover, it is determined that animal origin preservatives such as whey, honey, lysosomes of duck egg and chicken egg, chitosan have antimicrobial effect. Other than indigenous antimicrobials in foods, antimicrobial agents produced by microorganisms could be used as natural preservatives. The antimicrobial feature of preservatives depends on the antimicrobial spectrum, chemical and physical features of material, concentration, mode of action, components of food, process conditions, and pH and storage temperature. In this review, studies about antimicrobial components which are indigenous in food (such as herbal and animal origin antimicrobial agents), antimicrobial materials synthesized by microorganisms, and their usage as an antimicrobial agent to preserve foods are discussed.
Abstract: This study was set to determine the antimicrobial
activities of brine salting, chlorinated solution, and oil frying
treatments on enteric bacteria and fungi in Rastrineobola argentea
fish from fish landing beaches within L. Victoria basin of western
Kenya. Statistical differences in effectiveness of the different
treatment methods was determined by single factor ANOVA, and
paired two-tail t-Test was performed to compare the differences in
moisture contents before and after storage. Oil fried fish recorded the
lowest microbial loads, sodium chloride at 10% concentration was
the second most effective and chlorinated solution even at 150ppm
was the least effective against the bacteria and fungi in fish. Moisture
contents of the control and treated fish were significantly lower after
storage. These results show that oil frying of fish should be adopted
for processing and preserving Rastrineobola argentea which is the
most abundant and affordable fish species from Lake Victoria.