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PubMed2003

Growth kinetics and hydrolytic enzyme production of Pseudomonas spp. isolated from pasteurized milk.

Psychrotrophs, particularly Pseudomonas spp. are known to be the main determinants of the shelf-life of pasteurized milk and refrigerated raw milk. It is presumed that they mainly cause spoilage through the elaboration of proteinase and lipase enzymes. At the time of this research, under the relevant European Directive, one of the means of determining the quality of pasteurized milk was the pre-incubated count, which involves incubating the milk sample for 5 d at 6 degrees C followed by a plate count. Examination of numerous pre-incubated counts revealed a bimodal rather than a normal distribution indicating that the types of contaminants in pasteurized milk may be as important as their initial concentration. Pseudomonads that gave particularly high (> 5 x 10(6) cfu/ml) and low (< 10(3) cfu/ml) pre-incubated counts were isolated (high and low count isolates respectively). After the organisms had been subjected to a cold shock no consistent trend between the groups of isolates was detected with respect to lag phase duration. However, the high count isolates consistently had a faster exponential growth rate. Unexpectedly, with the exception of one isolate, the low count isolates produced detectable proteinase and lipase earlier. In addition, with one exception, maximal proteinase and lipase production was observed with the low count isolates. These findings indicate that there is no causal relationship between selective growth advantage and ability to produce proteinase and lipase. It also indicates that the spoilage of pasteurized milk is a complex phenomenon and is worthy of further research.

Animals↗

PubMedDate not supplied

Design and optimization of hot-filling pasteurization conditions: Cupuaçu (Theobroma grandiflorum) fruit pulp case study.

Cupuaçu (Theobroma grandiflorum) is an Amazonian tropical fruit with a great economic potential. Pasteurization, by a hot-filling technique, was suggested for the preservation of this fruit pulp at room temperature. The process was implemented with local communities in Brazil. The process was modeled, and a computer program was written in Turbo Pascal. The relative importance among the pasteurization process variables (initial product temperature, heating rate, holding temperature and time, container volume and shape, cooling medium type and temperature) on the microbial target and quality was investigated, by performing simulations according to a screening factorial design. Afterward, simulations of the different processing conditions were carried out. The holding temperature (T(F)) and time (t(hold)) affected pasteurization value (P), and the container volume (V) influenced largely the quality parameters. The process was optimized for retail (1 L) and industrial (100 L) size containers, by maximizing volume average quality in terms of color lightness and sensory "fresh notes" and minimizing volume average total color difference and sensory "cooked notes". Equivalent processes were designed and simulated (P(91)( degrees )(C) = 4.6 min on Alicyclobacillus acidoterrestris spores) and final quality (color, flavor, and aroma attributes) was evaluated. Color was slightly affected by the pasteurization processes, and few differences were observed between the six equivalent treatments designed (T(F) between 80 and 97 degrees C). T(F) >/= 91 degrees C minimized "cooked notes" and maximized "fresh notes" of cupuaçu pulp aroma and flavor for 1 L container. Concerning the 100 L size, the "cooked notes" development can be minimized with T(F) >/= 91 degrees C, but overall the quality was greatly degraded as a result of the long cooling times. A more efficient method to speed up the cooling phase was recommended, especially for the industrial size of containers.

Bacillus↗

PubMed2000

Effects of pulsed electric fields on the quality of orange juice and comparison with heat pasteurization.

Effects of pulsed electric fields (PEF) at 35 kV/cm for 59 micros on the quality of orange juice were investigated and compared with those of heat pasteurization at 94.6 degrees C for 30 s. The PEF treatment prevented the growth of microorganisms at 4, 22, and 37 degrees C for 112 days and inactivated 88% of pectin methyl esterase (PME) activity. The PEF-treated orange juice retained greater amounts of vitamin C and the five representative flavor compounds than the heat-pasteurized orange juice during storage at 4 degrees C (p < 0.05). The PEF-treated orange juice had lower browning index, higher whiteness (L), and higher hue angle (theta) values than the heat-pasteurized orange juice during storage at 4 degrees C (p < 0. 05). The PEF-treated orange juice had a smaller particle size than the heat-pasteurized orange juice (p < 0.05). degrees Brix and pH values were not significantly affected by processing methods (p > 0. 05).

Ascorbic Acid↗

PubMed2005

Stability and sensory shelf life of orange juice pasteurized by continuous ohmic heating.

Electrical heating of food products provides rapid and uniform heating, resulting in less thermal damage to the product. The objective of this research was to examine the effects of ohmic heating on the stability of orange juice with comparison to conventional pasteurization. During storage at 4 degrees C, degradation curves of ascorbic acid followed a linear decrease pattern in both ohmic-heated and conventionally pasteurized orange juices. For five representative flavor compounds (decanal, octana, limonene, pinene, and myrcene), higher concentrations were measured during storage in the ohmic-heated orange juice than in conventionally pasteurized juice. Although residual pectin esterase activity remained negligible in both types of juices, particle size was lower in the ohmic-heated orange juice. The sensory shelf life was determined by using the Weibull-Hazard method. Although both thermal treatments prevented the growth of microorganisms for 105 days, the sensory shelf life of ohmic-treated orange juice was >100 days and was almost 2 times longer than that of conventionally pasteurized juice.

Ascorbic Acid↗

PubMed2003

The effect of commercial steam pasteurization on the levels of Enterobacteriaceae and Escherichia coli on naturally contaminated beef carcasses.

The aim of the study was to assess the reduction achieved by steam pasteurization of beef carcasses of Escherichia coli, Enterobacteriaceae and total aerobic mesophilic plate counts (APCs). In total, 30 carcass halves were exposed to steam pasteurization (90 degrees C, 10 s exposure time) and the 30 corresponding carcass halves remained as untreated controls. The neck, midline and rump were sampled on each carcass half. Significant reductions in E. coli incidence (P < 0.05) and counts, 0.5 log10 CFU 1000 cm(-2) (P < 0.05), were observed on rump sites only. Significant reductions (>0.8 log10 CFU 1000 cm(-2)) of Enterobacteriaceae were observed at all carcass sites sampled (P < 0.05). Enterobacteriaceae reductions (>2 log10 CFU 1000 cm(-2)) were highly significant at the more contaminated sites (P < 0.001). Reductions in total APCs were inconsistent. Steam pasteurization significantly reduced the level of E. coli and Enterobacteriaceae at more contaminated sites, but did not result in complete decontamination. Therefore, steam pasteurization should be classed as an aid to hygienic beef processing, but not as a critical control point.

Abattoirs↗

PubMed2001

Pasteurized autogenous bone graft for reconstruction after resection of malignant bone and soft tissue tumors: imaging features.

Our experimental study revealed that pasteurization was sufficient for killing all tumor cells in any massive bone and that the osteoinductivity and mechanical strength of pasteurized bone were about same as that of a fresh bone graft and better than boiled or autoclaved bone. We have performed reconstruction surgery using pasteurized autogenous bone graft since 1990. Resected bone was warmed for 30 minutes in a homeothermal heater set at 60 degrees C and then placed back to the original anatomic site. The graft was fixed with a plate or intramedullary nail with or without bone cement. Based on our experience in 31 patients, no local recurrence was seen in the grafts. Among 24 patients who can be adequately evaluated, incorporation of graft was complete in 17 cases and partial in 4 cases. In 18 of 21 patients, uptake of radionuclide in the grafted pasteurized bone was detected on bone scintigraphy approximately 6 months after surgery, and the uptake increased gradually, which suggested revascularization and remodeling of grafted bone.

Adolescent↗

PubMed1989

Absence of anti-human immunodeficiency virus types 1 and 2 seroconversion after the treatment of hemophilia A or von Willebrand's disease with pasteurized factor VIII concentrate.

Patients with hemophilia A or von Willebrand's disease who are treated with concentrated preparations of human factor VIII made from unscreened pooled plasma are at substantial risk of contracting human immunodeficiency virus (HIV) infection. The purpose of this study was to investigate whether by treating such patients with a pasteurized factor VIII concentrate that had been heated in aqueous solution at 60 degrees C for 10 hours, HIV infection could be avoided. Eleven hemophilia centers in the Federal Republic of Germany and two in Austria identified 155 eligible patients who had been treated exclusively with pasteurized factor VIII concentrate and had not received any other blood products. Between February 1979 and December 1986 they received a total of 15,916,260 IU of pasteurized factor VIII. The United States was the source of 80 percent of the plasma from which the concentrate was made. By September 1988, these 155 patients had been screened for antibody to HIV type 1 (anti-HIV-1) with a total of 657 tests; all were negative. Sixty-seven patients were also tested once for antibody to HIV type 2 (anti-HIV-2); all these tests were negative as well. It appears that pasteurization effectively inactivates HIV, even in plasma that is likely to be highly contaminated with the virus.

Austria↗

PubMed2000

Low temperature pasteurization to reduce the risk of vibrio infections from raw shell-stock oysters.

Vibrio vulnificus and V. parahaemolyticus are natural inhabitants of estuarine environments and may be transmitted to humans by ingestion of raw oysters. This study focused on the use of low temperature pasteurization, to reduce these Vibrio spp. to nondetectable levels, thus reducing the risk of infection associated with raw oyster consumption. Artificially-inoculated V. vulnificus and V. parahaemolyticus and naturally-contaminated V. vulnificus in live oysters were pasteurized at 50 degrees C for up to 15 min. Samples of processed and unprocessed oysters were enumerated for V. vulnificus, V. parahaemolyticus, and aerobic spoilage bacteria for 0-14 days. Low temperature pasteurization was effective in reducing these pathogens from > 100,000 to non-detectable levels in less than 10 min of processing. Spoilage bacteria were reduced by 2-3 logs, thus increasing the shelf-life for up to 7 days beyond live unprocessed oysters. Vibrio vulnificus in control oysters was reduced by 10(2) during ice storage alone. Following pasteurization and during a temperature storage abuse study (24 h at 22 degrees C), V. vulnificus was not recovered. During this storage period spoilage bacteria exceeded 1 million/g oyster meat.

Animals↗

PubMed1988

Cleanup of biological extracts by a Pasteur pipette column and a comparison of in vivo-accumulated chlorinated pesticide residues with other clean up systems.

Biological samples are extracted with n-hexane/acetone (60:40) and 1 mL of the concentrated extract is eluted through a pasteur pipette column prepacked with alumina (0.3 g) and silicic acid (0.25 g) with 10 mL n-hexane (containing 4% acetone). The fat and other co-extractives are retained by the column and clear eluate is directly injected on a GLC column for determination on electron capture detector. A comparison of the Pasteur pipette cleanup with the modified method of Cole et al. (1967) on 41 samples of fish, One Step Method, (Ahmad and Marolt (1986] on 86 samples of fish and Maunder et al. (1964) on 10 type of wildlife (100 samples) was made. The Pasteur pipette method gives results which are significantly higher (p greater than 0.5) than the other methods except the One step method. The Pasteur pipette method has a detection limit of 0.01 microgram/g for DDT and its metabolites.

Acetone↗

PubMed2000

Efficacy of a washer-pasteurizer for disinfection of respiratory-care equipment.

We evaluated the efficacy of a commercial washer-pasteurizer. Carriers were inoculated with 10(4) to 10(6) test organisms and pasteurized at 170 degrees F for 30 minutes. Pasteurization eliminated all test organisms with the exception of Bacillus subtilis spores. Pasteurization appears efficacious for the disinfection of respiratory-care equipment and could result in a cost savings of approximately $30,000 per year.

Bacillus subtilis↗

PubMed2005

Establishment of minimum operational parameters for a high-volume static chamber steam pasteurization system (SPS 400-SC) for beef carcasses to support HACCP programs.

A static chamber steam pasteurization unit (SPS 400-SC()) was installed in a high-volume commercial beef slaughter facility. The SPS 400-SC consists of a three-phase carcass treatment cycle of water removal, steam pasteurization, and water chilling. Seven chamber temperatures (71.1, 73.9, 76.7, 79.4, 82.2, 85.0, and 87.8 degrees C) were evaluated at the midline area of pre-rigor beef carcasses. For each temperature evaluated, 20 carcass sides were randomly selected and aseptically sampled by tissue excision immediately before and after steam pasteurization to determine total aerobic bacteria, Enterobacteriaceae, generic E. coli, and total coliform populations. The 87.8 and 85.0 degrees C treatment temperatures were highly effective at reducing total aerobic bacterial populations, with log(10) reductions of 1.4 and 1.5 CFU/cm(2), respectively, from pretreatment mean population levels of 1.7 and 1.9 log10 CFU/cm(2). These temperatures also reduced Enterobacteriaceae, total coliforms, and generic E. coli to undetectable levels (<0.4 CFU/cm(2)) on all carcasses sampled. Treatment at 82.2 was marginally effective at reducing bacterial populations, while 71.1, 73.9, 76.7, and 79.4 degrees C treatments were ineffective at reducing microbial populations. In a Hazard Analysis Critical Control Points (HACCP)-based system employing steam pasteurization of carcasses as a critical control point, a critical limit of 85.0 degrees C as a minimum chamber temperature should be established, with a targeted operating temperature of 87.8 degrees C providing optimum antimicrobial activity.

Abattoirs↗

PubMed2004

Pasteurized autologous bone graft in surgery for bone and soft tissue sarcoma.

For skeletal reconstruction in surgery for bone tumors, pasteurization of bone has been used with favorable results over autoclaving or boiling. Twenty-three patients with primary malignant bone tumors and two patients with soft tissue sarcoma invading bone reconstruction surgery with pasteurized autologous bone graft comprised the study group. There were 16 females and nine males, between 7 and 77 years of age who were followed up for at least 3 years (mean, 52 months). The International Society of Limb Salvage graft evaluation method was used for evaluation of the radiographs. Fifteen patients (60%) had complete incorporation of the graft and eight patients (32%) had partial incorporation. Viability of the grafts was evaluated by bone scintigraphy. Of 22 patients evaluated, uptake was detected in 17 patients from approximately 6 months postoperatively after which it increased gradually. The functional results were assessed by the system of the Musculoskeletal Tumor Society, and the mean functional rating was 86%. Eighteen patients have been disease-free and seven have died of disease. Fracture (12%) and infection (20%) were the main complications. No local recurrence was detected. These results indicate that pasteurization of bone may be a useful option for reconstruction after resection of malignant bone tumors. The advantages of extracorporeal pasteurization include convenience of use, avoidance of intraspecies infection and allogenic reactions, and satisfactory bone remodeling.

Adolescent↗

PubMed2007

Pasteurized autograft for intercalary reconstruction: an alternative to allograft.

Intercalary resection and reconstruction for tumors have become increasingly popular. We asked whether pasteurized autologous bone graft was comparable to other reported reconstruction methods regarding union rates, complications, and functional outcomes. We retrospectively analyzed the outcome of 21 intercalary pasteurized bones in lower extremities. Ultimate graft survival, union rate, and union time were evaluated as a function of clinical variables, such as age, gender, body mass index, location of intercalary segment, primary tumor type, use of chemotherapy, percentage and length of resected bone, type of junction, method of fixation, and iliac bone graft at index operation. The overall survival rate of pasteurized bone was 74% at 10 years. We identified no clinical variables associated with graft survival or union time. The union rate was related to length or percentage of resected segment and location of osteotomy. The rates of infection, fracture, and nonunion were three of 21, two of 21, and five of 21, respectively. Our results suggest reconstruction with pasteurized autograft is a simple and easily accessible method in limb salvage and an economic alternative to allograft, with low rates of ultimate failure and graft-related complications.

Adolescent↗

PubMed1988

Growth and formation of toxin by Clostridium botulinum in peeled, inoculated, vacuum-packed potatoes after a double pasteurization and storage at 25 degrees C.

A process that claims to use a double pasteurization to produce vacuum-packed potatoes for storage at ambient temperature has been evaluated. After the first pasteurization, potatoes are vacuum-packed and stored at 25 degrees-35 degrees C for up to 24 h, which is intended to allow germination of bacterial spores, and are then pasteurized again. When potatoes were inoculated with spores of Clostridium botulinum and subjected to this double-pasteurization process a high proportion of spores remained viable and resulted in growth and formation of toxin within 5-9 d at 25 degrees C. To provide an appropriate reduction in the risk o survival and growth of Cl. botulinum, peeled, vacuum-packed potatoes for storage at ambient temperature should be given a heat treatment equivalent to an F(0)3 process. If they are not given such a heat treatment they should be stored at a temperature below 4 degrees C.

Botulinum Toxins↗

PubMed1986

Inactivation of the AIDS-causing retrovirus and other human viruses in antihemophilic plasma protein preparations by pasteurization.

Heat treatment at 60 degrees C for 10 h in solution (pasteurization) was introduced into the manufacturing process of antihemophilic cryoprecipitate (AHC) and factor VIII concentrates (F VIII) to reduce the risk of transmission of hepatitis to hemophiliacs. Since the acquired immunodeficiency syndrome (AIDS) may also be transmitted to hemophiliacs by antihemophilic plasma protein preparations, we have investigated inactivation of the AIDS virus HTLV III by pasteurization in AHC or F VIII and included in this study cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV), poliovirus and vaccinia virus. Each of these viruses was efficiently inactivated by pasteurization although considerable differences were observed between the different viruses HTLV III was rapidly inactivated, becoming nondetectable within 30-60 min. Our findings indicate that pasteurized AHC or F VIII should have a high margin of safety regarding the transmission of AIDS or any other infectious disease caused by viruses such as those tested.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Pasteurized tumoral autograft and adjuvant chemotherapy for the treatment of canine distal radial osteosarcoma: 13 cases.

OBJECTIVE: To report outcome in 13 dogs with distal radial osteosarcoma, without evidence of metastasis, treated by a combination of adjuvant chemotherapy and a pasteurized autograft limb-sparing procedure. STUDY DESIGN: Prospective clinical study. ANIMALS: Thirteen dogs with distal radial osteosarcoma. METHODS: Limb-sparing procedure was performed using an autograft from the excised tumoral segment, pasteurized at 65 degrees C for 40 minutes. Adjuvant chemotherapy (cisplatin or cisplatin and doxorubicin) was administered in all dogs. RESULTS: Mean and median survival times were 531 and 324 days, respectively (range, 180 to 1,868 days). Overall survival was 100% at 6 months, 50% at 12 months, 44% at 18 months, and 22% at 24 months. Lung metastasis occurred in 5 (38%) dogs. Observed complications were local recurrence (2 dogs, 15%), allograft infection (4 dogs, 31%), and implant failure (3 dogs, 23%). Limb function was good in 12 dogs (92%) and fair in 1 dog. CONCLUSIONS: Pasteurized bone autograft derived from the tumoral bone segment was an effective alternative to cortical bone allograft for limb sparing in canine distal radial osteosarcoma, in terms of feasibility, pattern of healing, complications, and survival. CLINICAL RELEVANCE: Use of a pasteurized bone autograft eliminates the need for a canine bone allograft bank and has the added advantage of good fit to the recipient site.

Animals↗

PubMed1987

Survival of Listeria monocytogenes in milk during high-temperature, short-time pasteurization.

Milk from cows inoculated with Listeria monocytogenes was pooled for 2 to 4 days and then heated at 71.7 to 73.9 degrees C for 16.4 s or at 76.4 to 77.8 degrees C for 15.4 s in a high-temperature, short-time plate heat exchanger pasteurization unit. L. monocytogenes was isolated from milk after heat treatment in six of nine pasteurization trials done at 71.7 to 73.9 degrees C and in none of three trials done at 76.4 to 77.8 degrees C. An average of 1.5 to 9.2 L. monocytogenes cells was seen in each milk polymorphonuclear leukocyte before heat treatment in 11 of 12 pasteurization trials. Noticeable degradation of leukocytes with intracellular listeria was detected in unpasteurized milk after 3 days of storage at 4 degrees C, and by 4 days of storage leukocytes had deteriorated to cellular debris, suggesting that holding unpasteurized milk refrigerated for 4 or more days would eliminate a protective effect leukocytes may provide for increasing heat resistance of L. monocytogenes. Results indicate that under the conditions of this study, L. monocytogenes can survive the minimum high-temperature, short-time treatment (71.7 degrees C, 15 s) required by the U.S. Food and Drug Administration for pasteurizing milk.

Animals↗

PubMed1999

Enhancement of solar water pasteurization with reflectors.

A simple and reliable method that could be used in developing countries to pasteurize milk and water with solar energy is described. A cardboard reflector directs sunshine onto a black jar, heating water to pasteurizing temperatures in several hours. A reusable water pasteurization indicator verifies that pasteurization temperatures have been reached.

Animals↗