The fate of bacteria contained in food during freezing, storage, and thawing is usually one that is detrimental. However, many microorganisms considered to have been killed by such treatments actually are only injured. Their viability can be determined by allowing the injury to repair in a non-selective medium before testing for their presence on selective media. Injured cells of pathogens have been found to be as pathogenic as uninjured ones; injured spoilage microorganisms can cause spoilage if permitted to repair and grow. Injured microorganisms and their potential importance in food safety and shelf-life constitute and important problem for the frozed food industry as well as the food sanitarian.

An Andersen Air Sampler was used to collect airborne microorganisms during the processing of cotton bales in a model card room. The instrument is convenient and practical for collecting and identifying viable airborne spores of fungi, bacteria, and actinomycetes present during cotton processing.

Soil Microbiology—It's a Small World. The accomplishments and personalities of some notable early American soil microbiologists are discussed. The tangled skeins of influences and interactions among them are used to justify the small world concept used in the title. In discussing the subject matter of soil microbiology, it is noted that as society becomes more concerned with population growth and world food supply, energy sources and requirements, and econology and the environment, soil microbiology is shifting its emphasis from soil and the growing plant to man and the biosphere. The soil microbiologist is becoming increasingly involved in exposing such unesthetic substrates as sewage, animal manures, and food and fiber processing and sanitary landfill organic wastes to microbial attacks. His objectives are to make such substrates less objectionable environmentally and to exploit their residual food and energy potentials. Together with these endeavors he is expanding his efforts to define the dominant roles of microorganisms in the functions of terrestrial ecosystems. Therein, microorganisms metabolize a far larger amount of the net primary productivity than do all of the higher forms of life, inclusive of man, taken collectively.

Applying three concentrations of 1,2-dibromo-3-chloropropane (DBCP) to a sandy clay loam soil increased the total oxygen consumed by microorganisms in the soil after 4 h. DBCP had no significant effect on the rate of oxygen uptake, the total oxygen consumption, and the number of bacterial colonies one week after treatment. After four weeks, however, the rate of oxygen uptake, the total oxygen consumed, and the number of bacterial colonies were higher (P = 0.05) in treated soil.

Characteristics of tests for protein quality in meat and poultry products are presented. Such tests must be reproducible, fast, low in cost, and must bear a constant relationship to the standard or benchmark method. At present, Protein Efficiency Ratio (PER) is the official procedure, but it is cumbersome and expensive. The advantages and disadvantages of tests for protein quality of human foods are assessed. Tests with humans, studies with rats, testing using microorganisms, and chemical assays are discussed.