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Clostridium acetobutylicum mutants BA 101 (hyperamylolytic) and BA 105 (catabolite depressed) were isolated by using N-methyl-N'-nitro-N-nitrosoguanidine together with selective enrichment on the glucose analog 2-deoxyglucose. Amylolytic enzyme production by C. acetobutylicum BA 101 was 1.8- and 2.5-fold higher than that of the ATCC 824 strain grown in(More)
Membrane fatty acid composition and thermal resistance (D value) of Pediococcus sp. were determined for mid-exponential-phase (ME) and stationary-phase (ST) cells grown in tryptic soy broth (TSB) and tryptone-glucose-yeast extract (TGY) at 28 and 37 degrees C. As the cells entered the stationary phase of growth, the unsaturated fatty acid, C18:1 n11c,(More)
Listeria monocytogenes is a food-borne pathogen capable of growth at refrigeration temperatures. Membrane lipid fatty acids are major determinants of a sufficiently fluid membrane state to allow growth at low temperatures. L. monocytogenes was characterized by a fatty acid profile dominated to an unusual extent (> 95%) by branched-chain fatty acids, with(More)
This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent) or form flocs/aggregates (also called granules) without use of chemicals and form thick layers of cells known as "biofilms." As a(More)
Amylolytic activity was primarily cell associated when Clostridium acetobutylicum was grown on glucose or maltose and primarily extracellular when grown on dextrin or starch. Total amylolytic activity decreased with increasing glucose concentration. When this microorganism was grown in P2 medium containing starch, the intracellular amylolytic activity was(More)
The ability of 71 strains of Salmonella enterica originating from produce, meat, or clinical sources to form biofilms was investigated. A crystal violet binding assay demonstrated no significant differences in biofilm formation by isolates from any source when tested in any of the following three media: Luria-Bertani broth supplemented with 2% glucose,(More)
The response of a potential nonpathogenic surrogate organism to a particular treatment should closely mimic the response of the target pathogenic organism. In this study, growth characteristics (generation time, lag phase duration, and maximum population), pH at stationary phase, and survival characteristics (level of attachment and survival on apple(More)
This study compared the efficacy of chlorine (20-200 ppm), acidic electrolyzed water (50 ppm chlorine, pH 2.6), acidified sodium chlorite (20-200 ppm chlorite ion concentration, Sanova), and aqueous chlorine dioxide (20-200 ppm chlorite ion concentration, TriNova) washes in reducing populations of Escherichia coli O157:H7 on artificially inoculated lettuce.(More)
Listeria monocytogenes is a food-borne pathogen with the ability to grow at refrigerator temperatures. Twelve cold shock proteins (Csps) with apparent M(r)s of 48,600, 41,000, 21,800, 21,100, 19,700, 19,200, 18,800, 18,800, 17,200, 15,500, 14,500, and 14,400 were induced by cold shocking L. monocytogenes 10403S from 37 to 5 degrees C, as revealed by(More)
Numerous outbreaks of salmonellosis by Salmonella Poona have been associated with the consumption of cantaloupe. Commercial washing processes for cantaloupe are limited in their ability to inactivate or remove this human pathogen. Our objective was to develop a commercial-scale surface pasteurization process to enhance the microbiological safety of(More)