微生物抗菌物在食品防腐中的应用

The application of microbial antibiotics,such as nisin and natnamycin,to food preservation,usage and tendency of them are reviewed.

Comparative Study of the Biological Activities of the Skin Secretions from Six Common Chinese Amphibians

Water soluble skin secretions of six common Chinese amphibians were studied for their biological and enzymatic activities.The skin secretions of Tylototriton verrucosus,Bombina maxima ,and Bufo andrewsi were found toxic to mice with the intraperitoneal LD 50 of 11 5?mg/kg,18 8?mg/kg,and 264?mg/kg,respectively.No acute lethal toxicities were observed for the skin secretions of Rana nigromaculata,Rana guentheri and Rana limnocharis in a dose up to 500?mg/kg.The lethal toxicities of the skin secretions of T verrucosus and B maxima to mice are in the same grade as those of Viperidae snake venoms.The toxic components in T verrucosus and B maxima skin secretions are the proteins with molecular weights ranging from 3 to 60?kDa.All the skin secretions had both proteolytic activity and trypsin inhibitory activity.The skin secretions from T verrucosus , B maxima and B andrewsi also displayed wide spectrum antimicrobial activity.On the other hand,the skin secretions from B andrewsi and B maxima showed cytotoxicity on human cancer cells.All the six samples had not significant effects on mammalian blood coagulation system.Phospholipase A 2 activity was only found in the skin secretions of T verrucosus .None of these skin secretions showed acetylcholine esterase activity.

Research Progress on the Control of Ginseng Gray Mold

This review article describes the research progresses on the control of ginseng gray mold, summarizes domestic and international related experimental re-sults and literature data using chemical fungicide, plant extracts, microbial prepara-tion and antagonistic bacteria to control ginseng gray mold, and final y puts forward the existing problem and future research direction of the treatment and control of ginseng gray mold.

Screening of Fnngos Antagonists against Six Main Disease Pathogens in Crops

28 soil samples were collected from the rhizosphere of 16 plant species in six different districts in Hunan. As a result of isolation and purification, 122 fungus strains were obtained of which the antagonistic activity was tested against six fungus pathogens in tomato, cotton, cucumber, chilli, rice and rape, and 17 strains were found antagonistic to one or more pathogenic fungi.

Effect of the Concentration of Spirulina platensis on the Growth of Bifidobacterium breve

The aim of this study is to demonstrate the influence of Spirulina platensis on the growth of Bifidobacteium breve in the infantile milk. The authors used a stump of Bifidobacterium breve isolated from the new saddles which was born after identification and characterization. The follow-up of the kinetics of growth of B. breve in the milk enriched by various concentrations of Spirulina （0, 1, 5 and 10 mg/mL） was realized, and the authors estimated the antimicrobial effect of the cultures realised on three pathogenic bacteria： a bacteria isolated from saddles ＂Salmonella ssp.＂, two reference stumps ＂Staphylococcus aureus ATCC25923＂ and ＂Escherichia coli ATCC25922＂. The growth rate was 0.11 hl for the culture of B. breve associated with Spirulina （10 mg/mL）, 0.09 hl for the culture of B. breve enriched with Spirulina （5 mg/mL） and 0.08 hl for the culture of B. breve enriched with Spirulina （1 mg/mL）. In the case of the pure culture of B. breve, the growth rate was 0.07 h1. The authors observed inhibitory effects of B. breve in the various cultures towards the considered pathogenic bacteria. The optimal antimicrobial activity was observed in the preculture bifid with the algae culture （10 mg/mL） towards Salmonella ssp. （Zi = 25 mm）, S. aureus ATCC25923 （Zi = 26 mm） and E. coli ATCC25922 （Zi = 28 mm）.

Application of Selected Natural Antimicrobial Formulations for the Control of Food Pathogens in Fresh-Cut Cauliflower

In recent years, research on biopolymer based-coating containing natural antimicrobial agents is developing significantly. The objective of this study was to evaluate the antimicrobial efficiency of six formulations containing pre-selected natural antimicrobial compounds against Listeria monocytogenes, Escherichia coli O 157：H7, Salmonella typhimurium, the total bacteria and total yeasts and molds in cauliflower. Each formulation was subjected to a sensory test in parallel to microbiological analysis and the efficiency during storage at 5 ℃ was evaluated for the two best formulations, based on their ability to eliminate the target microorganisms. Both formulations were able to reduce all pathogens and total flora below detectable levels after 24 h of storage at 5 ℃. Using washing or spraying treatments, the two formulations were able to reduce Listeria to undetectable levels for 3 d. This efficiency was extended to 7 d when the formulations were incorporated into an edible coating. Washing treatment with the two formulations was also able to limit the growth of yeast and molds at levels lower than 2 log, for more than 7 d. The population of E. coli was reduced to below the detection limit during 14 d of storage, after washing treatment with the two formulations. The spraying treatment of cauliflower with the formulations allowed the use of very small amounts of antimicrobials while maintaining a fairly good efficiency, greatly reducing the potential costs of implementing this method in the industry. Future research may focus on development of nanoemulsion of antimicrobial formulations based on the developed antimicrobial formulations in this study to improve the better coating efficiency.