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PubMed1976

Spiral plate count method for the examination of raw and pasteurized milk.

The spiral plate count method (SPLPC) was compared with the standard plate count (SPC) method by examining 201 samples of raw and pasteurized milk. Although the means of the two methods differed significantly at alpha = 0.01,the difference was less than 10% and was not considered to be of any practical importance. The pooled replicate variances of both methods were less than 0.003, indicating good agreement between duplicate plates, with the variance of the SPLPC slightly less than that of the SPC. We believe this study indicates that the SPLPC could be substituted for the SPC in the bacteriological examination of milk.

Animals↗
PubMed1978

Association of Yersinia enterocolitica with the manufacture of cheese and occurrence in pasteurized milk.

Raw milk in southern Ontario frequently contains Yersinia enterocolitica. The potential for transmission of this organism by cheese manufactured from unpasteurized milk was evaluated by examination of milk and cheese curd samples from cheese manufacturing plants and finished cheddar and Italian cheeses. The incidence of Y. enterocolitica was lower in cheese curd samples (9.2%) than in raw milk (18.2%). Most of the curd samples showed a positive phosphatase test, indicating production from raw milk. One curd sample yielded Y. enterocolitica after 4 weeks of storage at 4 degrees C but was negative after 8 weeks. All samples of cheddar and Italian cheeses, most of which showed a positive phosphatase test, were negative for Y. enterocolitica. One out of 265 samples (0.4%) of pasteurized fluid dairy products contained Y. enterocolitica.

Animals↗
PubMed1979

Pasteurization of salted whole egg inoculated with Arizona or Salmonella.

Recently, Arizona bacteria, close relatives of Salmonella, were recovered from salted whole egg that had been pasteurized by the presently recommended process of 63.3 degrees C (146 degrees F) for 3.5 min. Because of this and the fact that the heat resistance of Arizona in salted whole egg had not been determined, the present study was undertaken. Arizona or Salmonella, grown in Trypticase soy broth supplemented with 2% yeast extract in Fernbach flasks covered with aluminum foil over cotton and guaze at 35 degrees C with shaking at 176 rpm for about 96 h, were found to have the greatest degree of heat resistance. As expected, these cells, when inoculated into salted whole egg at 10(7) cells per ml, survived heating at 63.3 degrees C (146 degrees F) for 3.5 min in a two-phase slug flow heat exchanger. To consistently achieve a 7-log kill of typical Salmonella or Arizona, a treatment of 67 degrees C (152.6 degrees F) for 3.5 min was required. However, if a 7-log kill is mandatory, it remains to be determined whether this process affect the functional properties of this product.

Eggs↗
PubMed1999

2-Bromoethanesulfonate, sulfate, molybdate, and ethanesulfonate inhibit anaerobic dechlorination of polychlorobiphenyls by pasteurized microorganisms

Dechlorination of Aroclor 1242 by pasteurized microorganisms was inhibited by 2-bromoethanesulfonate (BES), sulfate, molybdate, and ethanesulfonate. Consumption of these anions and production of sulfide from BES were detected. The inhibition could not be relieved by hydrogen. Taken together these results suggest that pattern M dechlorination is mediated by spore-forming sulfidogenic bacteria. These results also suggest that BES may inhibit anaerobic dechlorination by nonmethanogens by more than one mechanism.

Journal Article↗
PubMed2003

Development of reverse transcription (RT)-PCR and real-time RT-PCR assays for rapid detection and quantification of viable yeasts and molds contaminating yogurts and pasteurized food products.

Reverse transcriptase PCR (RT-PCR) and real-time RT-PCR assays have been used to detect and quantify actin mRNA from yeasts and molds. Universal primers were designed based on the available fungal actin sequences, and by RT-PCR they amplified a specific 353-bp fragment from fungal species involved in food spoilage. From experiments on heat-treated cells, actin mRNA was a good indicator of cell viability: viable cells and cells in a nonculturable state were detected, while no signal was observed from dead cells. The optimized RT-PCR assay was able to detect 10 CFU of fungi ml(-1) in pure culture and 10(3) and 10(2) CFU ml(-1) in artificially contaminated yogurts and pasteurized fruit-derived products, respectively. Real-time RT-PCR, performed on a range of spoiled commercial food products, validated the suitability of actin mRNA detection for the quantification of naturally contaminating fungi. The specificity and sensitivity of the procedure, combined with its speed, its reliability, and the potential automation of the technique, offer several advantages to routine analysis programs that assess the presence and viability of fungi in food commodities.

Actins↗
PubMed2005

Molecular detection of Mycobacterium bovis and Mycobacterium bovis BCG (Pasteur) in soil.

PCR primers specific for the Mycobacterium tuberculosis complex were used to detect the presence of Mycobacterium bovis BCG (Pasteur) in soil microcosms and Mycobacterium bovis in environmental samples taken from a farm in Ireland with a history of bovine tuberculosis. M. bovis genes were detected in soil at 4 and 21 months after possible contamination. Gene levels were found in the range of 1 x 10(3) to 3.6 x 10(3) gene copies g of soil(-1), depending on the sampling area. Areas around badger setts had the highest levels of detectable genes and were shown to have the highest levels of gene persistence. M. bovis-specific 16S rRNA sequences were detected, providing evidence of the presence of viable cells in Irish soils. Studies of DNA turnover in soil microcosms proved that dead cells of M. bovis BCG did not persist beyond 10 days. Further microcosm experiments revealed that M. bovis BCG survival was optimal at 37 degrees C with moist soil (-20 kPa; 30% [vol/wt]). This study provides clear evidence that M. bovis can persist in the farm environment outside of its hosts and that climatic factors influence survival rates.

Agriculture↗
PubMed1982

Mechanisms of appearance of the Pasteur effect in Saccharomyces cerevisiae: inactivation of sugar transport systems.

Saccharomyces cerevisiae does not show a noticeable Pasteur effect (activation of sugar catabolism by anaerobiosis) when growing with an excess of sugar and nitrogen source, but it does do so after exhaustion of the nitrogen source in the medium (resting state). We have found that this different behavior of growing and resting S. cerevisiae seems due to differences in the contribution of respiration to catabolism under both states. Growing S. cerevisiae respired only 3 to 20% of the catabolized sugar, depending on the sugar present; the remainder was fermented. In contrast, resting S. cerevisiae respired as much as 25 to 100% of the catabolized sugar. These results suggest that a shift to anaerobiosis would have much greater energetic consequences in resting than in growing S. cerevisiae. In resting S. cerevisiae anaerobiosis would strongly decrease the formation of ATP; as a consequence, various regulatory mechanisms would switch on, producing the observed increase of the rate of glycolysis. The greater significance that respiration reached in resting cells was not due to an increase of the respiratory capacity itself, but to a loss of fermentation which turned respiration into the main catabolic pathway. The main mechanism involved in the loss of fermentation observed during nitrogen starvation was a progressive inactivation of the sugar transport systems that reduced the rate of fermentation to less than 10% of the value observed in growing cells. Inactivation of the sugar transports seems a consequence of the turnover of the sugar carriers whose apparent half-lives were 2 to 7 h.

Ammonium Chloride↗
PubMed1995

Evaluation of Sanofi Diagnostics Pasteur Chlamydia Microplate EIA shortened assay and comparison with cell culture and Syva Chlamydia MicroTrak II EIA in high- and low-risk populations.

Seven hundred thirty-two female urogenital samples were collected for Chlamydia trachomatis testing by both the Sanofi Diagnostics Pasteur (Chaska, Minn.) Chlamydia Microplate EIA by the shortened protocol and the Syva (San Jose, Calif.) MicroTrak II EIA, and the results were compared with those obtained by cell culture. For the analysis of samples from female patients, the patients were divided into high- and low-risk categories. An additional 121 male urethral samples were collected and tested by the Sanofi Microplate EIA and cell culture; for the analysis of samples from male patients, the patients were divided into asymptomatic and symptomatic categories. All specimens positive by enzyme immunoassay (EIA) were confirmed by a blocking assay following the respective manufacturer's instructions. Specimens negative by EIA that fell within a gray zone 30% below the cutoff and negative cultures with one or more corresponding positive EIA results were tested further by cytocentrifugation and direct immunofluorescent assay. The overall sensitivity, specificity, positive predictive value, and negative predictive value for Syva versus culture were 94, 98.8, 85.5 and 99.6%, respectively. After resolution, the results were 94.5, 99.6, 94.5, and 99.6%, respectively. The parallel results for the Sanofi Microplate EIA versus culture were 94.0, 98.7, and 83.9, and 99.6%, respectively, and after being resolved, the results were 94.9, 100, 100, and 99.6%, respectively. In the small male population tested, the resolved results of the Sanofi Microplate EIA versus culture demonstrated sensitivity, specificity, positive predictive value, and negative predictive value of 100, 100, 100, and 100%, respectively. The present study demonstrated that the Sanofi Microplate EIA shortened protocol is highly sensitive and specific in comparison with cell culture and the Syva MicroTrak II EIA.

Age Factors↗
PubMed2001

Transcription factor HIF-1 is a necessary mediator of the pasteur effect in mammalian cells.

The ability to respond to differential levels of oxygen is important to all respiring cells. The response to oxygen deficiency, or hypoxia, takes many forms and ranges from systemic adaptations to those that are cell autonomous. Perhaps the most ancient of the cell-autonomous adaptations to hypoxia is a metabolic one: the Pasteur effect, which includes decreased oxidative phosphorylation and an increase in anaerobic fermentation. Because anaerobic fermentation produces far less ATP than oxidative phosphorylation per molecule of glucose, increased activity of the glycolytic pathway is necessary to maintain free ATP levels in the hypoxic cell. Here, we present genetic and biochemical evidence that, in mammalian cells, this metabolic switch is regulated by the transcription factor HIF-1. As a result, cells lacking HIF-1alpha exhibit decreased growth rates during hypoxia, as well as decreased levels of lactic acid production and decreased acidosis. We show that this decrease in glycolytic capacity results in dramatically lowered free ATP levels in HIF-1alpha-deficient hypoxic cells. Thus, HIF-1 activation is an essential control element of the metabolic state during hypoxia; this requirement has important implications for the regulation of cell growth during development, angiogenesis, and vascular injury.

Adaptation, Physiological↗
PubMed1992

A pasteurized therapeutic plasma.

A process to subject pooled human plasma to a viral inactivation treatment by heating in the liquid state for 10 hrs at 60 degrees C (pasteurization) has been designed and evaluated. Activity recovered from clotting factors and protease inhibitors exceeded 80%. Overall clotting activity remained good. No activation of coagulation factors was detected. The process did not generate aggregates. No side effects (toxicity, hypotension, variation in heart rate, thrombogenicity) could be detected in animal models. Virus kill studies, using 7 lipid-enveloped and non-enveloped viruses including HIV-1 and Sindbis virus, revealed inactivation levels similar to those obtained for plasma derivatives. Thus, pasteurisation of human plasma can be achieved in conditions that allow good recovery of biological properties while ensuring a high degree of inactivation of lipid-enveloped and non-enveloped viruses.

Blood Banks↗
PubMed2002

Ecological interface design for Pasteurizer II: a process description of semantic mapping.

Ecological interface design (EID) is proving to be a promising approach to the design of interfaces for complex dynamic systems. Although the principles of EID and examples of its effective use are widely available, few readily available examples exist of how the individual displays that constitute an ecological interface are developed. This paper presents the semantic mapping process within EID in the context of prior theoretical work in this area. The semantic mapping process that was used in developing an ecological interface for the Pasteurizer II microworld is outlined, and the results of an evaluation of the ecological interface against a more conventional interface are briefly presented. Subjective reports indicate features of the ecological interface that made it particularly valuable for participants. Finally, we outline the steps of an analytic process for using EID. The findings presented here can be applied in the design of ecological interfaces or of configural displays for dynamic processes.

Animals↗
PubMedDate not supplied

[São Paulo Pasteur Institute Technique for estimating a canine population].

This paper describes a technique developed by the Pasteur Institute in São Paulo, Brazil, for counting and classifying a canine population according to levels of dependency and confinement. First, a household survey was performed to identify dogs with owners and their degree of restriction. Different-colored collars were given to totally and partially restricted dogs. Dogs cared for by individuals who did not consider themselves the owners received collars of a third color. After the survey, surveyors counted and recorded dogs on the streets according to the color of their collars. Absence of collars identified dogs without owners. Surveyors were positioned at predetermined sites, an average of 50 meters apart. Counting time lasted 30 seconds and was repeated every 10 to 15 minutes for one hour, with starting and finishing times signaled by blasts on a whistle. The technique was used in the city of Serra Azul, São Paulo, Brazil, by 13- to 17-year-olds after a one-day training program. A total of 498 dogs were recorded in two census tracts, 5% of which were classified as without owners and unrestricted.

Animal Identification Systems↗
PubMed2003

A protein kinase is located in the micellar fraction of fresh pasteurized skimmed farm milk.

Recombinant protein kinase CK2 from the yeast Schizosaccharomyces pombe is able to phosphorylate casein in skimmed pasteurized milk. We could incorporate up to 540 pmol of phosphate into 50 microg milk proteins, i.e., 0.26 P/mol caseins. To better understand the action of protein kinase CK2 on milk proteins, we have compared the action of rspCK2alpha on milk, and on different casein micellar subfractions isolated from milk by ultracentrifugation. In contrast to the situation observed with phosphocaseinate, alpha(s) casein was the best substrate for rspCK2alpha, whether milk or micellar fractions were used as substrates. We have characterized the protein content of different micellar fractions obtained by ultracentrifugation of cow milk using capillary zone electrophoresis. We confirm that the kappa casein content of micelles largely decreases when their size increases. In contrast, the alpha(s) casein content slightly increased with micelles size and beta casein content remained constant. All of the micellar fractions were substrates for rspCK2alpha, but a significant amount of intrinsic protein kinase activity was also found. The intrinsic protein kinase used added ATP as phosphate donor, and was only slightly sensitive to high heparin concentration. It could phosphorylate micellar casein in milk ultrafiltrate, in the absence of addition of any metallic cofactor. Its activity was only slightly affected by the addition of either MgCl2 or MnCl2. CaCl2 activated the enzyme significantly. The intrinsic kinase lost its activity with time, and could incorporate from 9 to 26% of the total phosphate incorporated in the presence of rspCK2a. Alpha(s) casein was the best substrate of the intrinsic kinase, followed by beta casein. In the presence of CaCl2, the intrinsic kinase was found to incorporate up to 470 pmol of phosphate into 50 microg of milk proteins.

Animals↗
PubMed2005

Short communication: Pasteurization of milk abolishes bovine herpesvirus 4 infectivity.

Bovine herpesvirus 4 (BoHV-4) is a gammaherpesvirus highly prevalent in the cattle population that has been isolated from the milk and the serum of healthy infected cows. Several studies reported the sensitivity and the permissiveness of some human cells to BoHV-4 infection. Moreover, our recent study demonstrated that some human cells sensitive but not permissive to BoHV-4 support a persistent infection protecting them from tumor necrosis factor-alpha-induced apoptosis. Together, these observations suggested that BoHV-4 could represent a danger for public health. To evaluate the risk of human infection by BoHV-4 through milk or serum derivatives, we investigated the resistance of BoHV-4 to the mildest thermal treatments usually applied to these products. The results demonstrated that milk pasteurization and thermal decomplementation of serum abolish BoHV-4 infectivity by inactivation of its property to enter permissive cells. Consequently, our results demonstrate that these treatments drastically reduce the risk of human infection by BoHV-4 through treated milk or serum derivatives.

Animals↗
PubMed2006

Effect of trisodium citrate concentration and cooking time on the physicochemical properties of pasteurized process cheese.

The effects of the concentration of trisodium citrate (TSC) emulsifying salt (0.25 to 2.75%) and holding time (0 to 20 min) on the textural, rheological, and microstructural properties of pasteurized process Cheddar cheese were studied using a central composite rotatable design. The loss tangent parameter (from small amplitude oscillatory rheology), extent of flow (derived from the University of Wisconsin Meltprofiler), and melt area (from the Schreiber test) all indicated that the meltability of process cheese decreased with increased concentration of TSC and that holding time led to a slight reduction in meltability. Hardness increased as the concentration of TSC increased. Fluorescence micrographs indicated that the size of fat droplets decreased with an increase in the concentration of TSC and with longer holding times. Acid-base titration curves indicated that the buffering peak at pH 4.8, which is due to residual colloidal calcium phosphate, decreased as the concentration of TSC increased. The soluble phosphate content increased as concentration of TSC increased. However, the insoluble Ca decreased with increasing concentration of TSC. The results of this study suggest that TSC chelated Ca from colloidal calcium phosphate and dispersed casein; the citrate-Ca complex remained trapped within the process cheese matrix. Increasing the concentration of TSC helped to improve fat emulsification and casein dispersion during cooking, both of which probably helped to reinforce the structure of process cheese.

Calcium↗
PubMed2007

Lipolysis in cheddar cheese made from raw, thermized, and pasteurized milks.

The evolution of free fatty acids (FFA) was monitored over 168 d of ripening in Cheddar cheeses manufactured from good quality raw milk (RM), thermized milk (TM; 65 degrees C x 15 s), and pasteurized milk (PM; 72 degrees C x 15 s). Heat treatment of the milk reduced the level and diversity of raw milk microflora and extensively or wholly inactivated lipoprotein lipase (LPL) activity. Indigenous milk enzymes or proteases from RM microflora influenced secondary proteolysis in TM and RM cheeses. Differences in FFA in the RM, TM, and PM influenced the levels of FFA in the subsequent cheeses at 1 d, despite significant losses of FFA to the whey during manufacture. Starter esterases appear to be the main contributors of lipolysis in all cheeses, with LPL contributing during production and ripening in RM and, to a lesser extent, in TM cheeses. Indigenous milk microflora and nonstarter lactic acid bacteria appear to have a minor contribution to lipolysis particularly in PM cheeses. Lipolytic activity of starter esterases, LPL, and indigenous raw milk microflora appeared to be limited by substrate accessibility or environmental conditions over ripening.

Animals↗
PubMed1986

Quality assessment of pasteurized fluid milk as related to lipopolysaccharide content.

A study was conducted to investigate any relationship between lipopolysaccharide (endotoxin) concentration in milk and parameters associated with the keeping quality of milk. Parameters investigated were flavor intensity, standard plate count, coliform count, psychrotrophic count, and gram-negative count. Lipopolysaccharide content was determined using the Limulus Amoebocyte Lysate assay. Pasteurized whole milk samples were obtained the day of processing in .94-L containers with samples analyzed on d 0 through 21. Significant linear relationships were detected between lipopolysaccharide concentration and days storage at 7 degrees C, flavor intensity, and psychrotrophic count.

Animals↗