Resistance of vegetative cells and endospores of Sporolactobacillus to gamma-irradiation.

Vegetative cells of Sporolactobacillus showed average resistance to gamma-irradiation compared to other vegetative bacteria with D10 values ranging from 0.350 to 0.525 kGy.

Physiology of Sporolactobacillus strains isolated from different habitats and the indication of in vitro antagonism against Bacillus species.

In an ecological study only low numbers of Sporolactobacillus were found in habitats such as the faeces of herbivores, the rumen of cattle and the final waste water of an abattoir. Their presence in the final waste water of an abattoir indicates their possible association with food, and, more specifically, with meat. Differences were found in some physiological characteristics.

Glucose metabolism by Lactobacillus divergens.

Earlier studies on the fermentation of D-[1-14C]- and D-[3,4-14C]glucose by Lactobacillus divergens showed that lactate was the major fermentation product and that it was probably produced by glycolysis. It was therefore recommend that L. divergens be reclassified as a homofermentative organism.

The influence of extrinsic factors on the microbiological spoilage pattern of ground beef.

Two hundred and thirty four samples of raw minced beef were subjected to storage at 0 and 7 degrees C over a period of 17 days. The samples were subjected to four different treatments where the controls (Treat 1) were aerobically packed. The vacuum-packed samples (Treats 2 and 3) differed only by the addition of 0.

Isolation of a DNA Probe for Lactobacillus curvatus.

A genomic library of Lactobacillus curvatus DSM 20019 was constructed in bacteriophage lambda gt11. A 1.2-kilobase DNA probe specific for L.

Proposed guidelines for maximum acceptable air-borne microorganism levels in dairy processing and packaging plants.

From the total number of air-borne microorganisms present per m3 of air, 1.5% were found to contaminate a dairy product while being packed into a container with an opening of 100 cm2 if it was exposed for 60 s. This value was used to compile a proposed guideline of maximum acceptable number of air-borne microorganisms per m3 which, if complied with, could ensure that no significant air-borne contamination of the product being packaged would take place.

Effect of reduced water activity on vegetative growth of cells and on germination of endospores of Sporolactobacillus.

Growth of vegetative cells and germination of endospores of Sporolactobacillus at reduced water activity (aw) values were studied with NaCl and glycerol as humectants, and compared with Bacillus cereus and Clostridium sporogenes. With NaCl the highest aw for complete inhibition of both growth of vegetative cells and germinated spores of Sporolactobacillus was 0.955.

Frequency and occurrence of Lactobacillus acidophilus in the gut of the pig, as indicated by its presence in the faeces.

Faecal samples of 2 pigs, kept on a constant diet, were analysed for Lactobacillus acidophilus and other lactic acid bacteria at 1 week intervals over a period of 3 months. Enumeration of L. acidophilus by selective methods was verified by phenotypic identification of representative isolates.

Conventional taxonomy of lactobacilli surviving radurization of meat.

All of the 113 catalase-negative, Gram-positive, rod-shaped strains isolated from radurized minced beef (5 kGy) were homofermentative, non-thermophilic, and belonged to the sub-genus Streptobacterium. The majority of the strains (100) were identified as Lactobacillus sake. These were divided into four sub-groups based on their sugar fermentation pattern: group IA1 (melibiose (+), maltose (-), amygdalin (-), 76 strains); group IA2 (melibiose (+), maltose (-), amygdalin (+), 14 strains); group IB1 (melibiose (+), maltose (+), amygdalin (+), four strains); group IB2 (melibiose (+), maltose (+), amygdalin (-), six strains).

Computer-based high resolution transmission ellipsometry.

A new transmission ellipsometric method-based on an eight-zone measurement-allows determination of birefringent properties of transparent systems and samples. In addition to well-known magnitudes (relative retardation Delta and polarization-dependent loss angle Psi) of reflection ellipsometry, two additional magnitudes-orientation of the optical axis phi and pseudoactivity angle rho-have to be ascertained. With a transmission ellipsometer working automatically on the basis of an eight-zone measuring method we attained resolution and reproducibility which is 1-2 decades better than that of commercial research reflection ellipsometers.

Radiation resistance of lactobacilli isolated from radurized meat relative to growth and environment.

Of 113 lactobacilli isolated from radurized (5 kGy) minced meat, 7 Lactobacillus sake strains, 1 L. curvatus strain, and 1 L. farciminis strain were used for radiation resistance studies in a semisynthetic substrate (i.

Antagonism of Lactic Acid Bacteria against Phytopathogenic Bacteria.

A variety of lactic acid bacteria, isolated from plant surfaces and plant-associated products, were found to be antagonistic to test strains of the phytopathogens Xanthomonas campestris, Erwinia carotovora, and Pseudomonas syringae. Effective "in vitro" inhibition was found both on agar plates and in broth cultures. In pot trials, treatment of bean plants with a Lactobacillus plantarum strain before inoculation with P.

Shelf-Life Extension of Minced Beef Through Combined Treatments Involving Radurization.

The effect of addition of glucose, lactic acid (LA) as well as radurization on several bacterial groups in refrigerated beef was investigated. Glucose added to meat in concentrations of 2 to 10% (w/w) had little influence on the bacteria monitored. Addition of LA to a pH of 5 had a marked effect on several bacteria groups in meat; the effect became more pronounced during storage.

Lactobacillus divergens sp. nov., a New Heterofermentative Lactobacillus Species Producing L(+)-Lactate.

A group of 8 heterofermentative Lactobacillus strains were isolated from raw vacuum-packaged, as well as SO(2)-treated, minced beef, in the course of shelf life studies on this product. These strains were found to differ from all other described heterofermentative Lactobacillus species in their production of virtually pure L( + )-lactic acid from hexoses and pentoses, and also in their low mol% G + C in the DNA (34 ± 0.8% G + C).

Evaluation of Three Carcass Surface Microbial Sampling Techniques.

Three carcass surface microbial sampling techniques were evaluated: a double swab, an excision and an agar sausage technique. In each instance, a sampling area of 6,42 cm was used. For the double swab technique, two sterile dry swabs were used.

Radurization of Prime Beef Cuts.

The bacteriology, organoleptic quality and shelf-life extension of radurized beef cuts were investigated. Application of doses of 2 kGy to vacuum-packed meat caused a considerable change in the bacterial population by elimination of the pseudomonads, Enterobacteriaceae and enterococci. The LLP group of lactic acid bacteria was relatively resistant to radiation, and after radurization was mostly comprised of Lactobacillus species.

High pressure cell for Raman scattering at low temperatures.

An optical cell suitable for Raman studies and for absorption studies of gases, liquids, and solids is described. The cell has been used at temperatures down to 4.2 K and pressures up to 10 kilobars.

High-pressure-low-temperature x-ray power diffractometer.

A high-pressure technique for x-ray diffraction studies at low temperatures is described. The system consists of a Bridgman anvil type high-pressure device with either tungsten carbide or boron carbide anvils, a liquid He cryostat, and x-ray diffractometer operating in Debye-Scherrer geometry. The newly developed boron carbide anvil cell is capable of containing a liquid pressure transmitting medium.

Adaption of a diamond anvil cell to an automatic four-circle diffractometer for x-ray diffraction.

A diamond anvil high-pressure device for x-ray diffraction on single crystals under hydrostatic pressures up to about 100 kilobars has been adapted to the automatic four-circle x-ray diffractometer Philips PW 1100. The mechanical adaption, the centering procedure, and quick pressure calibration on the diffractometer are described. Hints to improve the peak-to-background ratio of the intensity measurements are given.