Abstract: This text is designed for a second or subsequent course in microbiology in liberal arts food science, nutrition, or related course programs. Coverage includes: 1) history of food microbiology; 2) sources and types of microorganisms in food and parameters that affect the growth and activity of the food flora; 3) methods of determing microorganisms and/or their products in foods; 4) microbial food spoilage and preservation methods; 5) indicator and foodborne pathogens; and 6) psychrotrophs, thermophiles and radiation-resistant microorganisms. Each chapter contains an extensive reference list. The appendix includes a schematical depiction of the relationship between the common genera of foodborne bacteria.

This text is designed for a second or subsequent course in microbiology in liberal arts food science, nutrition, or related course programs. Coverage includes: 1) history of food microbiology; 2) sources and types of microorganisms in food and parameters that affect the growth and activity of the food flora; 3) methods of determing microorganisms and/or their products in foods; 4) microbial food spoilage and preservation methods; 5) indicator and foodborne pathogens; and 6) psychrotrophs, thermophiles and radiation-resistant microorganisms. Each chapter contains an extensive reference list. The appendix includes a schematical depiction of the relationship between the common genera of foodborne bacteria.

A detailed technical review discusses some of the basic concepts associated with the growth of microorganisms in meat and describes the characteristics, detection, and prevention of microbial spoilage of meats. Topics include: the microbial spoilage of meats. Topics include: the microbial spoilage of fresh and cured meats; the characteristic microorganisms causing spoilage and their detection and control; the effects of processing and packaging methods on microbial contamination in meat; and the functional use of microorganisms in meat processing. Microbiological standards for meats are discussed and further research needs are identified.(wz)

The examinations showed that frozen beef treated by microwave heat had a slightly increased total number of microorganisms, 655/g, in comparison to the average number, 602/g. The number of microorganisms in meat treated by heat in a conventional manner kept growing due to the temperature and duration of heat treatment and was 5.1 times higher than before the treatment. The results obtained indicated certain technological advantages of microwave heat treatment of frozen beef.

Measurements of rumen fluid ammonia concentration and disappearance of 16 roughages from nylon bags in the rumen were made on 4 rumen-cannulated Herefords. A deficiency of ammonia nitrogen substrate for rumen microorganisms reduced rumen microbial digestion of low-nitrogen roughages more than for high-nitrogen roughages. This may be because microorganisms digesting high-nitrogen forages obtained nitrogen directly from the forage and were thus less dependent on the rumen fluid ammonia pool.

For 33 months, variations in the total microbial population and in the number of ammonium and nitrite oxidizer microorganisms of a soil treated with or without cattle slurry were studied. The soil was a ranker over granite under grass. The treatment with cattle slurry significantly increased the total microbial population; the number of nitrifiers also increased but at a slower rate. The total microflora fell quickly after a short time; a second and or a third treatment did not show effect of the first one, but the reverse was true for the nitrifiers. After some time all the microorganisms tend to return to their initial levels though their densities were higher than the respective values of the unfertilized soil along the experimental period

Partial sterilization through the use of hot steam is one of the methods practiced in the glass houses conditions as an important measure to lower the diseases infection rate and the damage caused by the harmful microorganisms to the vegetable plants. In order to make a quantitative assessment of the microorganisms, the soil samples were analysed every five days. The total number of micro-organisms 8 hours after the thermal treatment, is reduced 182 and 76 times as compared with the untreated soil by heat. The microbiological equivalent is re-established 20-25 days after soil thermal treatment

Partial sterilization through the use of hot steam is one of the methods practiced in the glass houses conditions as an important measure to lower the diseases infection rate and the damage caused by the harmful microorganisms to the vegetable plants. In order to make a quantitative assessment of the microorganisms, the soil samples were analysed every five days. The total number of micro-organisms 8 hours after the thermal treatment, is reduced 182 and 76 times as compared with the untreated soil by heat. The microbiological equivalent is re-established 20-25 days after soil thermal treatment.

A study of the decomposition of fresh and pressed coffee pulp by microorganisms was carried out. The inoculum was obtained from the same pulp. Optimal conditions were sought in order to accelerate the decomposition. The transformation of this residue was monitored by means of the assay of total N, total P, ash, water content, organic C and C/N ratio. A temperature of 45ðC and the use of the inoculum served to accelerate decomposition of fresh pressed residues. The best degradation of fresh pulp was achieved when the yeast Hansenula polymorpha was employed. The decomposition of pressed pulp was achieved when a mixture of microorganisms from the same pulp was used, but this process was slower than the degradation of fresh pulp.