Hot Water Immersion Treatment Research Articles

Clinical Manifestations.

The accumulation of toxic amyloid-ß protein in brain is a hallmark of Alzheimer's disease. The accumulation of such toxicants is prevented by a cellular protein quality control system. Molecular chaperons, which further prevent proteins from misfolding and aggregating, are produced by this system, which is mostly activated in response to acute thermal stress. This study aims to determine the therapeutic effect of frequent thermal shock on the development of Alzheimer's disease METHOD: The induction of Alzheimer's disease was caused by the intracerebroventricular (ICV) injection of the Aß (1-42) peptide into the ventricular system of the mouse brain. The animals were divided into four groups: normal control (NC), disease control (DC), sham control (SC), water immersion/no heat group (NH), and hot water immersion/high heat group (HH). The ICV-Aß injection was given to the DC, NH, and HH groups to induce dementia and AD-like symptoms. The animals in the HH treatment group were given heat shock in the form of hot water immersion for a period of 4 weeks, where each session lasted for 20 minutes. The animals in the NH group were also exposed to water immersion for 20 minutes daily for a period of 4 weeks, but the water temperature was maintained at room temperature. After the completion of the treatment period, the behavioural and biochemical parameters of the animals were assessed for learning and memory defects. The enzyme-linked immunosorbent assay (ELISA) was carried out for the Aß estimation. Behavioural assessments in the Y-maze and morris water maze showed that the animals given daily heat exposure for a period of 4 weeks resisted the detrimental memory effects of the ICV-Aß injection and had better memory than the water immersion group with no heat treatment given. Increased levels of lipid peroxidation and decreased levels of glutathione were significantly (p<0.05) antagonised by hot water immersion treatment. ELISA showed the lower level of Aß in hot water immersion/high heat group animals when compared to the disease control animals. The study concluded that frequent heat exposure from hot baths and saunas may reduce the risk of developing dementia and Alzheimer's-like symptoms in old age.

Biology and management of hemp russet mite (Acari: Eriophyidae).

Hemp is rapidly becoming a crop of global agricultural importance, and one of the more serious pests of this crop is hemp russet mite (HRM) Aculops cannabicola (Acari: Eriophyidae). Significant knowledge gaps presently exist regarding critical aspects of pest biology, quantification of crop damage, and efficacy of pesticides. Here we assessed the role of cannabidiol (CBD) on HRM performance, efficacy of sulfur treatments in field trials, and effect of hot water immersion with and without surfactants in reducing HRM counts on hemp cuttings. We found that HRM fecundity was reduced on a high-CBD cultivar compared with a low-CBD cultivar in detached leaf assays. In contrast, HRM fecundity and survival were not impacted when reared on high-CBD diet in artificial feeding assays. This suggests that cannabinoids other than CBD may aid in reduction of mite populations on the high-CBD cultivar. Sulfur sprays reduced HRM populations by up to 98% with the greatest effects seen in plants receiving dual applications, one during the vegetative period in July and the second at the initiation of flowering in August. Yields of plants treated with sulfur increased by up to 33%, and there was a further increase in cannabinoid production by up to 45% relative to untreated plants. Hot water immersion treatments with and without surfactant solution reduced HRM on infested hemp cuttings, and no phytotoxicity was observed. This study provides novel approaches to mitigating HRM at multiple stages in hemp production.

Modification of Purun Tikus (Eleocharis dulcis) Long Fiber with Potential as Composite Reinforcement Material

The choice of natural fiber purun tikus (Eleocharis dulcis) as a composite reinforcement material is related to its benefits, such as low price, abundant quantity, renewable, and environmentally friendly. In this research, the effect of alkalizing treatment and hot water immersion on the properties of purun tikus fiber were investigated. The long fiber of purun tikus measuring 20 cm and diameter < 0.064 cm was modified with 120°C hot water immersion and 5% NaOH immersion for 1 hour each. These treatments were applied to improve the properties of purun tikus fiber, such as their properties of chemical (moisture, lignin, cellulose, and hemicellulose), physical (density), and mechanical (tensile strength). The results showed a decrease in the water content, lignin, cellulose, and hemicellulose of purun tikus fiber, while the density and tensile strength increased after the treatment of 120°C hot water immersion and NaOH 5% alkalization. The NaOH 5% alkaline treatment was better than 120°C hot water immersion in terms of reducing water content, lignin, cellulose, and hemicellulose. Although the tensile strength of the modified NaOH 5% NaOH purun tikus fibers is lower than the 120°C hot water immersion treatment, it was still higher than before the modification. It is shown that these fibers blend well in the manufacture of composite materials and improve their mechanical properties.

Post Harvest Treatment for Preserving Antioxidant Properties and Total Phenolic Content of Tomatoes and Litchis.

Fruits and vegetables are rich in antioxidants and polyphenols that help in prevention of many disorders like noncommunicable and degenerative diseases. However, they are highly susceptible to bacterial and fungal spoilage. In light of this, the present study aims to quantify the loss of antioxidant properties of litchis and tomatoes stored in the refrigerator for 21 days and to explore the protective effect of UV-C and hot water immersion treatment (HWT) to prevent, or atleast reduce, the effect of storage. Interestingly, both the treatments were able to reduce the loss of antioxidant properties in stored tomatoes, whereas, UV-C and HWT completely abrogated the storageinduced loss of antioxidant properties in litchis.

Influence of Indian cedar particle pretreatments on cement-wood composite properties

This work physically, mechanically, and chemically characterized the composites produced from Portland CP II-E32 cement and fresh Indian cedar wood particles previously treated by immersion in hot and cold water. Density values for wood particulate composites were around 50% lower compared with the wood-free control treatment, from 0.88 to 1.78 g/cm³. A larger swelling was observed for the composite material. The results of compressive strength and stiffness indicated that there is no need for particle treatment for composite production. Hot and cold water immersion treatments reduced the total Indian cedar wood extractives by 33% and 42%, respectively. Optical microscopy analysis was used to identify adhesion failures between the cement/wood interface of the composite produced with fresh particles, which presented a higher percentage of extractives. This result indicated that the greater concentration of total extractives partially inhibits the matrix-matrix interaction reinforcement. Despite the reduction in total extractives caused by the treatments, this process is not necessary for the composite production because there is no statistical difference between the treatments. The values obtained for the composite indicate the possibility of application in sealing blocks in light construction systems.

Tensile shear strength of natural wood decorative plywood from lesser known Sungkai (Peronema canescens) tree

Sungkai (Peronema canescens) small logs has been harvested from a private sungkai plantation (Sabahpuri Nursery Sdn Bhd) in Telipok, Sabah. The logs were then rotary peeled to 0.6mm thick and made into 4’ x 4’, 3 plies Urea Formaldehyde (UF) plywood with Acacia Hybrid wood used as the core veneer (1.2 mm thick) at a local plywood facility; Cymao Plywood Sdn Bhd in Sandakan. Remaining dried veneer were brought back to University Malaysia Sabah for further study. Laboratory scale 3 plies plywood (Sungkai-Acacia, Sungkai-Seraya) were made using the same source of UF resin and veneer, and used for comparison studies. Commercial 3 plies Nyatoh plywood were also used as control samples. The samples were then tested according to Japanese Agricultural Standard for Plywood 2003 (amended: 2008) Tensile Shear Strength of Type II Natural Wood Decorative Plywood. All of the samples pass the Tensile Shear Strength (TSS) minimum standard of 0.7 N/mm2 in untreated condition or even after hot and cold water immersion treatment. The untreated mill samples of Sungkai-Acacia plywood perform the best with mean TSS = 1.74 N/mm2, SE = 0.05 while Nyatoh shows the lowest mean tensile shear strength with 1.06 N/mm2, SE = 0.07. Further statistical analysis shows there was no significance difference between Sungkai mixed plywood group samples. However, Sungkai mixed plywood samples shows a significant difference (p < 0.05) with superior strength when compared to commercial Nyatoh plywood samples. If these criteria met the final requirement for the end use of the veneer, then the potential of Sungkai as an alternative or supplemental raw material is something worth given due consideration.

Effect of the Combination Hot Water - Calcium Chloride on the In Vitro Growth of Colletotrichum gloeosporioides and the Postharvest Quality of Infected Papaya.

Anthracnose of papaya fruit caused by the fungus Colletotrichum gloeosporioides is one of the most economically important postharvest diseases. Hot water immersion (HW) and calcium chloride (Ca) treatments have been used to control papaya postharvest diseases; however, the effect of the combination HW-Ca on the pathogen growth and the development of the disease in infected papaya fruit has been scarcely studied. The aim of this study was to evaluate the effect of the HW-Ca treatment on the in vitro growth of C. gloesporioides conidia and the quality of infected papaya. In vitro, the HW-Ca treated conidia showed reduced mycelial growth and germination. In vivo, the HW-Ca treatment of infected papaya delayed for 5 days the onset of the anthracnose symptoms and improved the papaya postharvest quality. The combined treatment HW-Ca was better than any of the individual treatments to inhibit the in vitro development of C. gloeosporioides and to reduce the negative effects of papaya anthracnose.

Interfacial Phenomena and Mechanical Behavior of Polyetheretherketone/Polybenzimidazole Blend under Hygrothermal Environment.

Demands for engineering applications of high performance polymers, such as the polyaryletherketone families, have grown significantly in recent years. Fundamental knowledge on the mechanical behavior of such polymers, especially under harsh environments, is still lacking. In this study, the mechanical behavior and interfacial phenomena of a blend of polybenzimidazole (PBI) particles having sizes of about 50 μm and polyetheretherketone (PEEK) matrix at 50:50 weight ratio was characterized. PBI and PEEK are known to be incompatible with each other in the dry state. The possible influence of hygrothermal exposure on interfacial bonding between PEEK and PBI has been systematically studied. Under dry conditions, the PEEK matrix dominates the dynamic mechanical behavior, indicating no noticeable viscoelastic coupling between the two phases. After being exposed to hygrothermal conditions, the Tg of the PEEK phase in the blend shifts to a lower temperature by as much as 26 °C. The extent of this shift is much greater than what is observed for neat PEEK alone under the same condition. Nanomechanical property mapping results indicate that the interfacial region is broadened after 288 °C hot water immersion treatment. The above finding strongly suggests the hygrothermal conditioning promotes apparent compatibility between PEEK and PBI. Likewise, the fracture behavior of the blend provides direct evidence that the interfacial adhesion is greater than the cohesive strength of either phase after water immersion. In the meantime, it is found that both fracture toughness and tensile strength of the blend are improved by water absorption at 60 °C, at the expense of a minor reduction in Young's modulus. However, if the blend is exposed to hot water at 288 °C, all of the mechanical properties will deteriorate significantly. The possible causes of the mechanical property deterioration in the PEEK/PBI blend after hygrothermal treatment are discussed.

Fruit Description and Evaluation of Five Treatments to Break Seed Dormancy of Brownlowia peltata Benth.

&lt;p class="Els-Abstract-text"&gt;&lt;em&gt;Brownlowia peltata &lt;/em&gt;Benth. is a native tree from Borneo, in its germination problem was physical dormancy due to the hard pericarp of the fruit. The study aimed to evaluate five treatments for breaking the seed physical dormancy and the fruit description. The experiment was using Randomized Complete Block Design (RCBD) with four different temperatures of water immersion, a scarification, and control. The fruit of &lt;em&gt;B. peltata&lt;/em&gt; was a woody follicle; belong to yellow green group 148 A in color; 29.64 mm in long; 21.62 mm in thickness; 29.86 mm in wide, with an average weight of 12.05 g. Hot water immersion treatment of 40 °C for 60 s; 60 °C for 60 s and 80 °C for 30 s could raise the fruit moisture content of 0.92 % to 1.04 %. There was a significant difference on germination rate coefficient and coefficient of uniformity of germination among treatments. The mature seed does not have a physical dormancy once the carpel splits and create a slit (fruit opening).&lt;/p&gt;&lt;div&gt;&lt;p class="Els-keywords"&gt;&lt;strong&gt;Keywords:&lt;/strong&gt; &lt;em&gt;Brownlowia pellata &lt;/em&gt;Benth; dormancy; fruit; seed; viability.&lt;/p&gt;&lt;/div&gt;

Adenosine triphosphate assay of Bactrocera dorsalis (Diptera: Tephritidae) eggs treated with low or high temperatures

A bioluminescent adenosine triphosphate (ATP) assay using a luciferin-luciferase reagent was conducted as a viability test for Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) eggs treated with low or high temperatures to evaluate the potential into use for quarantine operations. ATP concentrations in B. dorsalis eggs treated with different temperatures, including freezing, cold treatment, and rapid and slow heating, simulating a hot water immersion treatment and vapor heat treatment, respectively, were measured. Mean ATP concentrations in untreated eggs decreased as egg age increased. For freezing and rapid heating, the mean ATP concentrations in treated eggs significantly decreased 24 h after the treatments, and the maximum ATP concentrations were lower than the minimum ones for untreated eggs. Most ATP concentrations in the cold treatment group exceeded the minimum ones in untreated eggs. Mean ATP concentrations in eggs treated with slow heating decreased less than those in eggs treated with rapid heating. There is potential to use ATP assays in plant quarantine operations for the rapid determination of the viability of fruit fly eggs treated with hot water immersion, although more validation research is first required. Verification tests should be performed by applying ATP assays during quarantine, by using flies and host fruit subjected to different temperature treatments.

Flexural and hydrothermal aging behavior of silk fabric/glass mat reinforced hybrid composites

Recycled natural materials such as silk fabric have attracted more and more public attention over the past few years. In this research, unsaturated polyester resin was used as matrix, glass mat and silk fabric were employed as reinforcement to fabricate the laminated hybrid composites by hand lay-up method. Three-point flexural quasi-static and load-controlled low cycle bending fatigue (LCBF) tests at 55 %, 70 % and 85 % pre-set load levels were performed. The composite specimens were also subjected to hot water immersion treatment at 80 oC for different durations. The effects of the immersion treatment on the bending and impact fracture characteristics were investigated. The results showed that higher flexural modulus and strength were obtained when silk fabric layer was stacked at the middle layer. It seems that the antifatigue property was improved by the inclusion of silk fabric reinforced in glass mat hybrid composites. In the water immersion experiments, both the flexural properties and impact properties were improved initially until reaching the maximum and then decreased continuously with further increase in exposure time. These seemingly contradictory behaviors are due to relaxation of the internal stress, swelling of the silk fibers and the weakening of fiber/matrix interface.

Inactivation of Salmonella in Shell Eggs by Hot Water Immersion and Its Effect on Quality.

Thermal inactivation kinetics of heat resistant strains of Salmonella Enteritidis in shell eggs processed by hot water immersion were determined and the effects of the processing on egg quality were evaluated. Shell eggs were inoculated with a composite of heat resistant Salmonella Enteritidis (SE) strains PT8 C405, 2 (FSIS #OB030832), and 6 (FSIS #OB040159). Eggs were immersed in a circulating hot water bath for various times and temperatures. Come-up time of the coldest location within the egg was 21 min. SE was reduced by 4.5 log at both hot water immersion treatments of 56.7 C for 60 min and 55.6 °C for 100 min. Decimal reduction times (D-values) at 54.4, 55.6, and 56.7 °C were 51.8, 14.6, and 9.33 min, respectively. The z-value was 3.07 °C. Following treatments that resulted in a 4.5 log reduction (56.7 °C/60 min and 55.6 °C/100 min), the surviving population of SE remained static during 4 wk of refrigerated storage. After processing under conditions resulting in 4.5 log reductions, the Haugh unit and albumen height significantly increased (P < 0.01) and yolk index significantly decreased (P < 0.05). The shell dynamic stiffness significantly increased (P < 0.05), while static compression shell strength showed no significant difference (P < 0.05). Vitelline membrane strength significantly increased (P < 0.05); although, no significant difference (P < 0.05) was observed in vitelline membrane elasticity. In summary, the hot water immersion process inactivated heat resistant SE in shell eggs by 4.5 log, but also significantly affected several egg quality characteristics.

Antioxidant phytochemical and quality changes associated with hot water immersion treatment of mangoes (Mangifera indica L.)

Mangoes are an important tropical fruit crop worldwide and are best noted for their vibrant flesh colour, juicy texture, and sweet flavour, along with important nutrient contributions from their phytochemical constituents. Mangoes imported to the US must be exposed to thermal quarantine treatments, such as irradiation and hot water treatment (HWT), to eradicate invasive pests, yet limited data exist regarding polyphenolic changes to the fruit following hot water immersion treatment. Although the water temperature remains constant, the duration of treatment depends on fruit size. Therefore, these investigations focused on polyphenolic and antioxidant changes to mature, green mangoes following varying times of HWT and their changes during short-term storage. Experimentally, fruit were immersed in 46.1 °C water from 70 to 110 min; half evaluated within 2 h of treatment, while the remainder was evaluated after 4 days of storage at 25 °C for changes in polyphenolics, antioxidant capacity and fruit quality. Free gallic acid and four gallotannins were tentatively identified as the major polyphenolics present by HPLC analysis against authentic standards. Two major polyphenolics in mango, gallic acid and gallotannins, as well as total soluble phenolics, decreased as a result of prolonged HWT, while the antioxidant capacity remained unchanged in all heat-treated mangoes immediately after HWT. However, during 4 days storage, only minor changes were observed in gallic acid and gallotannin concentrations whereas total soluble phenolics and antioxidant capacity in all hot water-treated fruits decreased. The optimum hot water immersion times did not affect the external quality and polyphenolics of mangoes but all heat treatments reduced total soluble phenolics and antioxidant capacity, regardless of the duration of treatment times, during 4 days storage.

Effective Heat Treatment Techniques for Control of Mung Bean Sprout Rot, Incorporable into Commercial Mass Production

Seedlot disinfection techniques to control mung bean sprout rot caused by Colletoricum acutatum and C. gloeosporioides were evaluated for commercial production scheme. Soaking seedlots in propolis (100 X) and ethanol (20% for 30 min) appeared promising with control values of 85.5 and 80.8 respectively, but still resulted in up to 20% rot incidence. None of the C. acutatum conidia survived through hot water immersion treatment (HWT) for 10 min at temperatures of 55, 60 and , whereas the effective range of the dry heat treatment (DHT) was . Tolerance of mung bean seedlot, as estimated by hypocotyl elongation and root growth, was lower for HWT than for DHT. Germination and growth of sprouts were excellent over the range of intervals, except for HWT at for 5 min. At this marginal condition, heat damage appeared so that approximately 2% of seeds failed to sprout to normal germling and retarded sprouts were less than 5% with coarse wrinkled hypocotyls. These results suggested that DHT would be more feasible to disinfect mung bean seedlots for commercial sprout production. Heat treatment at above ranges was highly effective in eliminating the epiphytic bacterial strains associated with marketed sprout rot samples. HWT of seedlot at 55 and for 5 min resulted in successful control of mung bean sprout rot incidence with marketable sprout quality. DHT at 60 and for 30 min also gave good results through the small-scale sprouting system. Therefore, we optimized DHT scheme at 60 and for 30 min, considering the practical value of seedlot disinfection with high precision and accuracy. This was further proved to be a feasible and reliable method against anthracnose incidence and those bacterial strains associated with marketed sprout rot samples as well, through factory scale mung bean sprout production system.

열처리에 의한 콩나물 탄저병의 방제

콩나물 탄저병균 포자에 대한 열처리효과를 조사한 결과 <TEX>$65^{\circ}C$</TEX>에 30분까지 건열처리 하였을 때는 균의 사멸효과가 50% 정도에 불과하여, 건열처리는 나물콩 살균에 활용할 수 없었다. 병원균은 <TEX>$55^{\circ}C$</TEX>에서 20분 이상, 또는 <TEX>$60^{\circ}C$</TEX>에서 5분간 습열처리하면 완전히 사멸하였고, 부생성 세균 사멸효과도 높은 것으로 나타났다. <TEX>$55^{\circ}C$</TEX>에서 5분간 습열처리 조건하에서는, 발아장애 및 하배축 기형은 발생하지 않았으나, 20%의 탄저병균 분생포자가 생존하였기 때문에 실용적가치가 인정되지 않았다. 따라서 종자발아 및 하배축 기형이 발생하지 않는 최적 열처리 조건인 <TEX>$60^{\circ}C$</TEX>에서 5분간 습열처리를 실제 콩나물 재배 공정모델에 적용한 결과 탄저병 발생이 완전히 방제되어, 품질이 우수한 콩나물을 생산하게 되었다 따라서 이는 확립된 부패방지기술로서 적용이 가능하다고 판단되었다. Anthracnose fungus was most pathogenic on soybean sprout, of the fungi and bacteria isolated from rotten sprout on market. Bacterial strains associated were not virulent. Dry heat (DHT) applied even as high as <TEX>$65^{\circ}C$</TEX> for 30min. was not effective enough to eliminate the artificially inoculated Colletotrichum gloeosporioides propagules from seedllots. Hot water immersion treatment (HWT), at elevated temperature of <TEX>$55^{\circ}C$</TEX> for 20 min, did eliminate the pathogen but reduced seed germinating and retarded sprout growth: Seed germination was practically acceptable when the seedlots were exposed to at <TEX>$55^{\circ}C$</TEX> for 5 min, but about 20% anthracnose propagules survived. Accordingly, we have optimized the HWT scheme for 5 min at <TEX>$60^{\circ}C$</TEX>. This scheme was validated, at small to large scale production system, that surely rule out the possible carry over of the bacterial contaminant from seedlots. This result should improve the shelf-life of soybean sprout on the market.

Hot-Water Immersion Quarantine Treatment Against Mediterranean Fruit Fly and Oriental Fruit Fly (Diptera: Tephritidae) Eggs and Larvae in Litchi and Longan Fruit Exported from Hawaii

Immersion of litchi fruit in 49 degrees C water for 20 min followed by hydrocooling in ambient (24 +/- 4 degrees C) temperature water for 20 min was tested as a quarantine treatment against potential infestations of Mediterranean fruit fly, Ceratitis capitata (Wiedemann); and oriental fruit fly, Bactrocera dorsalis Hendel, eggs or larvae in Hawaiian litchi, Litchi chinensis Sonnerat. The 49 degrees C hot-water immersion of litchi provided probit 9 (99.9968% mortality with >95% confidence) quarantine security against eggs and first instars. There were no survivors from 15,000 each feeding and nonfeeding Mediterranean fruit fly or oriental fruit fly third instars immersed in a computer-controlled water bath that simulated the litchi seed-surface temperature profile during the 49 degrees C hot-water immersion treatment. Litchi served as the model for longan, Dimocarpus longan Lour., a closely related fruit that is smaller and also has commercial potential for Hawaii. Modified fruit infestation and holding techniques used to obtain adequate estimated treated populations from poor host fruit, such as litchi and longan, are described. Data from these experiments were used to obtain approval of a hot-water immersion quarantine treatment against fruit flies for litchi and longan exported from Hawaii to the U.S. mainland.

Moisture absorption studies of sisal fibre reinforced polypropylene composites

In this research, sisal fibre reinforced polypropylene (SF/PP) composites were prepared by injection moulding using a pre-coating technique that we have developed earlier. The composite specimens were subjected to hot water immersion treatment at 90 °C for different durations. The effects of the immersion treatment on the tensile and impact fracture characteristics were investigated. The apparent weight gain and weight loss curves were constructed. From the weight loss curves for the individual composites, the weight loss within the induction period was negligible. At the end of the induction period, the weight loss increased sharply. Due to the weight loss and the formation of additional moisture diffusion paths as immersion treatment proceeds, the apparent weight gain was non-Fickian. Both the tensile modulus and tensile strength of the SF/PP composites decreased continuously with increasing water immersion time. On the contrary, the Izod impact strength increased initially with immersion treatment. After reaching the maximum impact strength, the impact strength was found to decrease with further increase in immersion time. These contradictory behaviours between the tensile and impact properties were explained by the plasticization of the SF/PP interface and the swelling of the reinforcing sisal fibres.

Incidence, internalization and behavior of Salmonella in mangoes, var. Tommy Atkins

Mangoes imported from South America were responsible for two Salmonella multistate outbreaks in the USA. The hot water immersion treatment utilized for fly larvae control was pointed out as the probably responsible for bacterial internalization in these fruits. The objective of this study was to evaluate: the presence of Salmonella in mangoes, the occurrence of internalization of these bacteria during a laboratory-simulated hydrothermal treatment and the bacterial behavior in mangoes in the rind surfaces and in different portions: stem end, middle side and blossom-end after storage at 8 and 22 °C, for 24 and 144 h. One hundred samples were analyzed; Salmonella was not found in any of the 33 samples destined for the export market, but in two of the remaining samples, destined for the internal market, the presence of that bacterium was detected. The results from the laboratory-simulated experiments proved that bacterial internalization occurred in the intact fruit. In the stem portion the log of MPN/g of bacteria was statistically higher than in the remaining parts of the fruit ( p < 0.05), demonstrating that the stem is the route for bacterial entrance. At 22 °C bacterial multiplication was observed in all portions (the rind surface, stem end, middle side and blossom-end) analyzed. However, at 8 °C the growth was lower, and in the rind surface there was a decrease in the number of bacteria. Thus, microorganisms present in the water used for hydrothermal treatments can migrate to the interior of mangoes, survive and grow in all fruit portions.

Perspectives on Postharvest Biopesticides and Storage Technologies for Organic Produce

Fewer postharvest technologies are available for use on organic than conventional fruits and vegetables. Even though biopesticides are perceived as likely candidates for postharvest use on organic produce, only some biopesticides will be approved as organic compounds for various reasons. An example is the definition of a biopesticide used by regulatory agencies such as the EPA which includes compounds that will not be considered organically acceptable. Fortunately, there are other existing or new technologies that could be acceptable on organic fruits and vegetables. Some examples are hot water immersion treatment or a hot water rinsing and brushing, new innovative controlled atmosphere techniques, alternative sprout control agents, naturally occurring volatiles and biofumigants. More research is needed on each of these technologies, both singly and in combination with each other.

Ripening Behavior and Quality of `Brazilian' Bananas following Hot Water Immersion to Disinfest Surface Insects

The fruit quality and ripening response of `Brazilian' bananas (Musa sp., group AAB) were determined following hot water immersion treatments for surface disinfestation. Summer-harvested fruit were exposed to 47, 49, or 51 °C water for 10, 15 and 20 minutes and ripened at 20 °C. The summer experiment established the exposure time and temperature limits for fruit injury. Winter-harvested fruit were immersed in 48, 49, or 50 °C water for 5, 10 and 15 minutes, stored for 12 d at 14 °C, and ripened at 22 °C. The hot water exposure time had a greater effect than the water temperature on banana fruit ripening. Nontreated bananas ripened after 13 to 15 d, and ripening was delayed by 2 to 7 d when fruit were exposed for 15 or 20 minutes to hot water. Hot water treatments did not inhibit pulp softening, but peels tended to be firmer for bananas immersed in 49 to 51 °C water than control fruit. Heat-treated bananas were not different from control fruit in soluble solids content or titratable acidity, however the conversion of starch to sugars was reduced at higher temperatures and exposure times. Bananas exposed for 20 minutes to hot water had delayed respiratory peaks and ethylene production, especially at 51 °C. Mild peel injury was observed on fruit exposed to higher temperatures (49 to 51 °C) for longer durations (15 or 20 minutes).