Microwave cooking has increased in popularity in recent years. Since the time to process food is much shorter than with conventional methods, questions have been raised as to the microbial safety of foods cooked with microwaves. The first part of this review includes discussions on the importance of intrinsic and extrinsic characteristics of foods in relation to destruction of microorganisms in microwave-cooked foods, the mechanism of microwave destruction of microorganisms and viewpoints on the thermal and nonthermal destruction of microorganisms. The second part includes data on the effect of time and temperature on microorganisms in microwave-cooked foods, the effect of microwave destruction of microorganisms in different food systems and the effect of microwaves on different bacteria. The last section includes discussions of destruction of microorganisms by microwave cooking of meats, poultry and egg products, dairy products, cereal products, fruit products, vegetables and miscellaneous foods. We observed that (a) microwave heating of food is more “food dependent” than conventional heating, (b) the manufacturer-recommended microwave treatment time for some foods may not destroy high levels of bacteria, (c) use of microwaves in combination with other conventional heating methods results in more uniform heating in foods and destruction of bacteria, (d) heat generated by microwaves kills naturally-occurring microorganisms as long as the size and type of food are carefully correlated with exposure time, (e) microwaves exert different killing effects on individual bacterial species and (f) the question of thermal versus nonthermal effects of microwaves on microorganisms has not been settled. We believe microwave heating is an important method for processing of foods at home, in institutions and in commercial operations. The process is acceptable from the standpoint of food spoilage and food safety as long as the users understand the limitations and possibilities of microwave heating and are aware of some of the major points presented in this review.

Formic, acetic and propionic acids in various combinations and individually were screened for antimicrobial efficacy and effect on meat color. Microorganisms tested were two pseudomonads, three coliforms, a Streptococcus sp., a Micrococcus sp., a spore-forming bottom yeast and three film yeasts which reproduced by budding. Variables tested were microorganism, pH, concentration of sanitizer and exposure time. When the 11 cultures were exposed to individual sanitizers and mixtures of them in three replications, 2% formic acid and 1% formic plus 1% acetic acid were most effective, destroying 84 and 73%, respectively, of the test cultures. Three microorganisms that were refractory to 2% acetic acid were usually killed by 2% formic acid. Addition of ascorbic acid to the sanitizer to reduce oxidation of the meat pigments resulted in lowered microbial counts. Color was not affected by addition of 1% ascorbic acid. With added 5% ascorbic acid, discoloration was noticeable but not extensive. There was no effect of pH on microbial destruction at the concentration of acid used, However, more microorganisms were killed as time of exposure to the acid was increased.

Biological control of Rhizotonia bataticola on gram by coating seed with antagonistic microorganisms was investigated. Initially microorganisms were selected from bacteria and actinomycetes isolated from a loam soil and creeened for antagonism to R. bataticola on potato dextrose agar. Four bacterial isolates and six actinomycete isolates proved antagonistic to R. bataticola in petridish tests and were tested further by coating gram seed in field soil inoculated with R. bataticola. These antagonists significantly reduced symptoms caused by R. bataticola and also increased plant growth and dry matter production of gram. However, a strain of Streptomyces was ineffective and did not control disease

Jute is a rainy season crop. Highland which is suitable for the cultivation of Olitorius are comparatively scanty. Capsularis are popular as early maturing crop. The study describes the retting process of jute. It also indicates that retting can be effected either through microorganisms, chemicals or enzymes. Retting can be done exclusively by the action of chemicals using dilute acids or alkalies i.e. without the intervention of microorganisms in order to overcome the slowness inherent in microbiological process, but it has not been tried in large scale trials. Chemical retting has not made much progress in England. Bacterial enzymes and a fungal enzyme named Hiparol have been isolated in India and Bangladesh.

damage produced by unidentified microorganisms in epithelial cells of middle intestine of Anopheles albimanus (a principal vector of malaria), possible use in biological control: Colombia