Commercial Sterilization Research Articles

Comparison of effect of microwave sterilization and pasteurization on qualities of kiwi juice

This study was conducted to investigate the comparison of effects of microwave sterilization and pasteurization on nutrient components and physio-chemical properties of kiwi juice based on the achievement of commercial sterilization requirements separately. “Gui Chang” kiwi, produced from Xiuwen in Guizhou Province, which was used as raw materials for processing, and the effects of microwave sterilization and pasteurization on total number of bacteria, pH value, soluble solid content, color, total acid, total sugar, polyphonols, VCand SOD in kiwi juice were determined. The results showed that different sterilization methods had no significant effect on pH, soluble material, total sugar and total acid (p>0.05) when compared with control group. The content of VCin kiwi juice decreased after pasteurization (p 0.05) after microwave sterilization. Those indicated that microwave sterilization could better maintain the color and nutrients in kiwi juice. Therefore, microwave sterilization technology not only achieved good bacterial effect but also to ensure maximum quality of kiwi juice.

Ready-to-Serve Crab Sandwich Spread in Retort Pouch: Product Development and Process Optimization

A ready-to-serve sandwich spread was developed from the meat of mud crab, Scylla serrata, by thermal processing in retortable pouches in an overpressure retort at temperatures 111.1, 116.1, and 121.1°C; and F0 values 5, 6, and 7 min. Process optimization was done by evaluating the samples for texture, color, commercial sterility, thiobarbituric acid (TBA) value, and sensory evaluation. All samples were found to be acceptable based on these quality evaluations, and together with principal component analysis (PCA), the sample processed at 116.1°C, 6 min was found to be the best, with cook value of 84.29 and total process time of 42.59 min.

Kinetic study of the thermal denaturation of a hyperthermostable extracellular α-amylase from Pyrococcus furiosus

Hyperthermophilic enzymes are of industrial importance and interest, especially due to their denaturation kinetics at commercial sterilisation temperatures inside safety indicating time–temperature integrators (TTIs). The thermal stability and irreversible thermal inactivation of native extracellular Pyrococcus furiosus α-amylase were investigated using differential scanning calorimetry, circular dichroism and Fourier transform infrared spectroscopy. Denaturation of the amylase was irreversible above a Tm of approximately 106°C and could be described by a one-step irreversible model. The activation energy at 121°C was found to be 316kJ/mol. Using CD and FT-IR spectroscopy it was shown that folding and stability greatly increase with temperature. Under an isothermal holding temperature of 121°C, the structure of the PFA changes during denaturation from an α-helical structure, through a β-sheet structure to an aggregated protein. Such data reinforces the use of P. furiosus α-amylase as a labile species in TTIs.

The combined effect of nisin, moderate heating and high hydrostatic pressure on the inactivation ofBacillus sporothermoduransspores

To investigate the combined effect of hydrostatic pressure (HP), moderate temperature and nisin on the inactivation of Bacillus sporothermodurans spores which are known to be contaminant of dairy products and to be extremely heat-resistant. A central composite experimental design with three factors, using response surface methodology, was used. By analysing the response surfaces and their corresponding contour plots, an interesting interaction with the three factors was observed. The inactivation observed was shown to be well fitted with values predicted by the quadratic equation, since the adjusted determination coefficient (R(adj)(2)) was 0·979. The optimum process parameters for a 5-log spores ml(-1) reduction of B. sporothermodurans spores were obtained, 472 MPa/53°C for 5 min in presence of 121 UI ml(-1) of nisin. Nisin and temperature treatments improve the effectiveness of pressure in the inactivation of highly heat-resistant spores of B. sporothermodurans. This study shows the potential of using high HP for a short time (5 min) in combination with moderate temperature and nisin to inactivate B. sporothermodurans spores in milk. Such treatments could be applied by the dairy industry to ensure the commercial sterility of UHT milk.

The microbiological profile of Jamaican Ackees (Blighia sapida)

PurposeThe aim of this paper is to study the microbiological profile of the ackee fruit during maturation.Design/methodology/approachAckees at ripening stage five, mature but unopened, were allowed to ripen naturally on the trees or on ripening racks used in commercial processing. The microbiological profile of fruits from this stage to that where they had ripened to the point just prior to decay (stage ten) were assessed. Aerobic and anaerobic mesophilic and thermophilic sporeformers and vegetative cells, total coliforms, E. coli, lactic acid bacteria, yeasts and molds at each stage were determined using standard methods.FindingsThe number of microorganisms on the tree‐ripened fruits was higher than those ripened on racks. Mesophilic aerobic and anaerobic spore‐forming organisms were present in greater numbers than thermophiles at all stages of maturity. Coliforms, excluding E. coli, were found on the tree‐ripened ackees particularly in the latter stages of ripening. Lactic acid bacteria and yeasts and molds found on both tree and rack‐ripened fruit may be the predominant agents in the microbiological spoilage of ackees during ripening.Originality/valueThis study is the first to assess the microbiological profile of ackees during ripening. It indicated that the relatively low levels of microorganisms of economic or public health significance during both tree‐ and rack‐ripening processes would not affect the commercial sterility of the canned product, even with a moderate thermal process (Fo of 3). It also suggests that controlled rack‐ripening of ackee fruit during commercial processing could improve the microbial quality of the processed product.

Comparing the Effects of Ultra‐High‐Pressure Homogenization and Conventional Thermal Treatments on the Microbiological, Physical, and Chemical Quality of Almond Beverages

The effects of ultra-high-pressure homogenization (UHPH) at 200 and 300 MPa, in combination with different inlet temperatures (55, 65, and 75 °C) on almond beverages with lecithin (AML) and without lecithin (AM), were studied. UHPH-treated samples were compared with the base product (untreated), pasteurized (90 °C, 90 s), and ultra-high-temperature (UHT, 142 °C, 6 s) samples. Microbiological analysis, physical (dispersion stability, particle size distribution, and hydrophobicity), and chemical (hydroperoxide index) parameters of special relevance in almond beverages were studied. Microbiological results showed that pressure and inlet temperature combination had a significant impact on the lethal effect of UHPH treatment. While most UHPH treatments applied produced a higher quality of almond beverage than the pasteurized samples, the combination of 300 MPa and 65 and/or 75 °C corresponded to a maximum temperature after high pressure valve of 127.7 ± 9.7 and 129.3 ± 12.6 °C, respectively. This temperature acted during less than 0.7 s and produced no bacterial growth in almond beverages after incubation at 30 °C for 20 d. UHPH treatments of AML samples caused a significant decrease in particle size, resulting in a high physical stability of products compared to conventional heat treatments. UHPH treatment produced higher values of hydroperoxide index at day 1 of production than heat-treated almond beverage. Hydrophobicity increased in AML-UHPH-treated samples compared to AM and conventional treatments. Ultra-high-pressure-homogenization (UHPH) is an emerging technology, a potential alternative to conventional heat treatments. It is a simple process consisting of single step. When liquid food (almond beverage in this study) passes through the high-pressure valve, a very good stability and reduction of microorganisms is achieved, both effects due to the particle breakdown. Specific UHPH conditions could produce commercial sterilization of almond beverage.

Parâmetros de qualidade da anchoita (Engraulis anchoita) enlatada

This study was conducted to elaborate the canned anchovy (Engraulis anchoita), and to evaluate the canning process, the physical-chemical and microbiological characteristics of the canned product. The canned anchovies were prepared with two topping liquids, employing different brine and pre-cooking times, which resulted in eight treatments. These samples were analyzed to determine the physical-chemical and microbiological characteristics, and the commercial sterility was assessed. The microbiological parameters were in compliance with the canned fish legislation in force. The canned anchovies submitted to brine for five minutes, preserved in tomato sauce and without pre-cooking procedure showed the highest percentage of sodium chloride contents (0.24 %) and of ashes (4.10 %). The canned anchovies preserved in sunflower oil, submitted to brine for two minutes, and pre-cooked showed the highest proteins contents (16.97 %).

IMPROVED MANUFACTURING CANNED "COMPOTE CHERRY" USING COMBINED HEAT TREATMENT

The results of studies on the development of new modes of heat sterilization compote cherry using stepwise heating in a stream of hot air and hot water dushevaniem air cooled rotating container. Revealed that the modes provide commercial sterility of finished products, reducing the length of the heat treatment and the quality of the finished product. Are some of the modes of heat sterilization step of cherry compote in a stream of heated air and water dushevaniem air-cooled rotating container.

Sequential preheating and transglutaminase pretreatments improve stability of whey protein isolate at pH 7.0 during thermal sterilization

Whey protein isolate (WPI) is a potential ingredient to manufacture shelf-stable transparent beverages if proteins are heat stable, i.e., without causing turbidity, precipitation and gelation after the required thermal processing to obtain commercial sterility (138 °C for 8 s or longer). However, information is lacking about stability of WPI during heating at 138 °C. Furthermore, novel technology and mechanistic understanding on how to produce clear products after heating systems with >5% WPI, particularly with salt, is needed. In this work, 5% w/v WPI was pretreated by microbial transglutaminase (mTGase) at three levels for 1–15 h at 50 °C, with and without prior preheating at 80 °C for 15 min. Heat stability of the pretreated samples at pH 7.0 and 0, 50, and 100 mM NaCl was evaluated at 138 °C. Samples pretreated by mTGase for a greater extent demonstrated improved heat stability. Samples subjected to sequential preheating and mTGase pretreatments produced clear dispersions even after heating at 138 °C for 30 min in the presence of 0 and 50 mM NaCl at pH 7. All pretreatments increased the magnitude of zeta-potential and resistance against thermal denaturation. The sequentially-pretreated WPI was the most heat-resistant, having decreased hydrodynamic diameter (<36 nm) during extended heating at 138 °C and 50 mM NaCl. The present study demonstrates the feasibility of using sequential preheating and mTGase pretreatments to develop sterilized beverage products with a high content (5% w/v) of whey protein and yet of transparent appearance at ambient temperatures.

Canning of vegetable-type soybean in acidified brine: Effect of the addition of sucrose and pasteurisation time on color and other characteristics

The objective of this work was to evaluate the effect of adding sucrose and pasteurisation time of the canning vegetable-type soybean in acidified brine on the color of grains by using central composite design rotational (DCCR) 22. Chemical, physical and microbiological characteristics of the canned grains of vegetable-type soybean in acidified brine were evaluated, and the results were compared with in natura grains and canning of vegetable-type soybean without sucrose. The optimum conditions for the formulation of the canned vegetable-type soybean grains in acidified brine were established, after validation of the proposed model, as being 3.43g 100mL−1 sucrose, 6g 100mL−1 NaCl2, 0.29g 100mL−1 CaCl2 and citric acid with pH 3.9 and a thermal processing time of 10min. Commercial sterility was achieved in all the canned vegetable-type soybean. The in natura grains showed higher hardness and green colors when compared with the canning vegetable-type soybean with and without sucrose probably due the thermal processing that caused softening of cells wall and loss color. The addition of sucrose in the acidified brine contributed to maintain the desirable color of canning vegetable-type soybean grains. The canned in acidified brine presented a high content of glucose and fructose and low content of sucrose and stachyose when compared with in natura soybean grains. The thermal processing canned vegetable-type soybean in acidified brine with addition sucrose promoted an increase in isoflavone glycosides content, reduced the malony-glycosil content and was unable to convert the isoflavones to aglycones.

Inactivation of Bacillus sporothermodurans LTIS27 spores by high hydrostatic pressure and moderate heat studied by response surface methodology

Bacillus sporothermodurans is a milk spoilage bacterium producing resistant endospores that survive ultra-high temperature treatment. The inactivation of B. sporothermodurans LTIS27 spores by combined hydrostatic pressure and heat treatments was studied. A central composite experimental design was used to evaluate the effect of pressure (300–500 MPa), temperature (30–50 °C), and pressure-holding time (10–30 min) on the inactivation of spores in distilled water and skim milk. The inactivation observed was shown to fit well with the values predicted by the quadratic equation, since Radj2 were 0.970 and 0.977 in distilled water and milk, respectively. By analyzing the response surface plots, the inactivation was shown to be higher in distilled water than in milk under all the conditions tested. This was probably due to a protective effect of milk against inactivation by pressure. The optimum process parameter values for a 5-log cycle reduction of spores were calculated as 477 MPa/48 °C for 26 min and 495 MPa/49 °C for 30 min in water and in milk, respectively. This study shows the efficiency of hydrostatic pressure in combination with moderate temperature to inactivate B. sporothermodurans spores. Such treatments could be applied by the dairy industry to ensure the commercial sterility of UHT milk.

Computational Fluid Dynamics Modeling of the Thermal Processing of Canned Pineapple Slices and Titbits

Thermal processing of canned fruits is an important preservation technique used to increase the shelf life of canned foods through the inactivation of spoilage microorganisms and enzymes. The objective of this study was to develop a computational fluid dynamics model to investigate the temperature profiles during the thermal processing of canned pineapple products. Two different kinds of products such as canned pineapple slices and titbits were analyzed to investigate the effect of size reduction of the product on the efficacy of heat transfer during thermal processing. The simulation results were validated with the experimental measurements of temperatures. The temperature profile, slowest heating zone (SHZ), and the effects of natural convection and conduction heating on canned pineapple slices and titbits were studied. In the canned pineapple slices, the SHZ was found to lie inside the pineapple slices. In contrast, for the pineapple titbits, the SHZ was present at the bottom of the can. The pineapple titbits were found to achieve a rapid temperature increase owing to the combined effects of buoyancy-induced natural convection and increased surface area available for higher heat transfer. This finding signifies the retention of the nutritive properties of pineapple by preventing the loss of heat-labile nutrients like vitamins without compromising the commercial sterility of the product.

Plasma Sterilization of Pharmaceutical Products: From Basics to Production

AbstractFor the first time, a commercial low pressure plasma sterilization system integrated in a pharmaceutical filling line is presented. The route from a laboratory plasma reactor to an industry scale plasma sterilization reactor is shown. Absolutely calibrated measurements (e.g. OES and Langmuir probe) yield to a knowledge transfer from an experimental set‐up to an industrial reactor. Spore count reduction of 4 log in 10 s of Geobacillus stearothermophilus and Bacillus subtilis spores prove the applicability of an industrial grade plasma sterilization reactor for transfer isolators typically used in pharmaceutical filling and packaging lines.magnified image

Avaliação da qualidade tecnológica apresentada por tilápia do Nilo (Oreochromis niloticus) enlatada

The fish is quite sensitive to the deterioration due to the high activity of water and, especially to a near pH of the neutrality. The application of the heat needs a rigorous control of time and temperature. The objective of this work developed meat of tilapia canned in vegetable edible oil, for the use from the nonstandard raw material, in order to offer a product with high collected value. The meat of tilapia were taken to the daily pay-cooking in fluent steam for approximately 50 minutes, when the oil of covering was next added, when re-drove and been subdued to two thermal treatments respectively of 15 and 30 minutes in autoclave 121°C. After that the microbiological analyses were carried out, chemical-physically and sensory. The microbiological evaluation showed that the products were presenting satisfactory conformable quality to legislation. The pickles of tilapia presented next composition centesimal: moisture 48.4 %; ashes 3.1 %; protein 12.2 %; lipids 32.7 %; chloride 0.8 %. The sensory analysis showed what, did not exist significant difference at the level of 5 % in the different treatments. The test of commercial sterility was carried out also, where two thermal treatments were adapted to maintain the quality of the pickle of tilapia canned. It was ended that, the pickles of tilapia, they presented quality compatible with similar products, confirming the viability of production of this product.

Food safety objective approach for controlling Clostridium botulinum growth and toxin production in commercially sterile foods.

As existing technologies are refined and novel microbial inactivation technologies are developed, there is a growing need for a metric that can be used to judge equivalent levels of hazard control stringency to ensure food safety of commercially sterile foods. A food safety objective (FSO) is an output-oriented metric that designates the maximum level of a hazard (e.g., the pathogenic microorganism or toxin) tolerated in a food at the end of the food supply chain at the moment of consumption without specifying by which measures the hazard level is controlled. Using a risk-based approach, when the total outcome of controlling initial levels (H(0)), reducing levels (ΣR), and preventing an increase in levels (ΣI) is less than or equal to the target FSO, the product is considered safe. A cross-disciplinary international consortium of specialists from industry, academia, and government was organized with the objective of developing a document to illustrate the FSO approach for controlling Clostridium botulinum toxin in commercially sterile foods. This article outlines the general principles of an FSO risk management framework for controlling C. botulinum growth and toxin production in commercially sterile foods. Topics include historical approaches to establishing commercial sterility; a perspective on the establishment of an appropriate target FSO; a discussion of control of initial levels, reduction of levels, and prevention of an increase in levels of the hazard; and deterministic and stochastic examples that illustrate the impact that various control measure combinations have on the safety of well-established commercially sterile products and the ways in which variability all levels of control can heavily influence estimates in the FSO risk management framework. This risk-based framework should encourage development of innovative technologies that result in microbial safety levels equivalent to those achieved with traditional processing methods.

Action of successive heat treatments in bovine milk fatty acids

The action of successive pasteurization thermal treatments (75 oC for 15 s) and commercial sterilization by indirect heat exchange (140 oC for 6 s) was analyzed on the lipid profile of bovine milk. Raw milk samples were submitted to pasteurization and then were submitted to sterilization (ultra-high temperature, UHT). The fat of raw milk, pasteurized milk and commercially sterilized milk samples was extracted. After transesterification, the fatty acid methyl esters (FAMEs) were analyzed by gas chromatography with flame ionization detector (GC-FID). The quantification of fatty acids (FA) revealed that for most of the found fatty acids there was no significant difference (p > 0.05) between raw milk and pasteurized milk. However, it was found significant differences for 21 of the 26 analyzed fatty acids (p > 0.05) for the raw and sterilized milks, including the predominant isomer of the conjugated linoleic acid (CLAc9t11) of the milk. This fact evidences the successive action of heat treatments on milk lipid profile.

Characterisation and stability of quality indices on storage of pumpkin (Cucurbita moschata and Cucurbita maxima) purees

SummaryPurees of Cucurbita moschata‘Menina Brasileira’ and of Cucurbita maxima‘Exposição’ pumpkins were produced. A commercial sterilisation test confirmed the effectiveness of the thermal treatment applied in the production. The stability was monitored during storage in ambient conditions. No significant alterations in pH, titratable acidity or soluble solids were noted. Both types of puree have a good concentration of carotenoids, although a slight decrease was detected in the ‘Exposição’ pumpkin puree after 15 days of storage. In relation to the colour of the purees, there were no significant alterations in a*, b* or ΔE during storage. Decreases in L* and WI were detected after 30–60 days of storage, thus suggesting a browning in an initial period. However, the scores given by the sensory assessors remained above 7 in a 9‐point scale, thus showing no significant alterations during storage. The results showed the stability of the pumpkin purees during the 180 days of storage under the proposed conditions.

Evaluation of potential induced radioactivity in medical products as a function of electron energy in electron beam sterilization

Commercial sterilization of medical devices may be performed using electron beam irradiators at various electron energies. The potential for activating components of the devices has been discussed, with current standards stating that electron energy greater than 10 MeV requires assessment of potential induced radioactivity. This paper evaluates the potential for induced activity in medical products sterilized in electron beam as a function of the electron maximum energy. Monte Carlo simulation of a surrogate medical device was used to calculate photon and neutron fields resulting from electron irradiation, which were used to calculate concentrations for several radionuclides. The experiments confirmed that 10 MeV is a conservative assumption for limiting induced radioactivity. However, under the conditions as evaluated, which is a limited total quantity of metal in the material being irradiated and absent a limited number of elements; the amount of induced activity at 12 MeV could also be considered insignificant. The comparison of the sum-of-fractions to the US Nuclear Regulatory Commission exempt concentration limits is less than unity for all energies below 12.1 MeV, which suggests that there is minimal probability of significant induced activity at energies above the 10 MeV upper energy limit.

UHT Milk Processing and Effect of Plasmin Activity on Shelf Life: A Review

Abstract: The demand for ultra‐high‐temperature (UHT) processed and aseptically packaged milk is increasing worldwide. A rise of 47% from 187 billion in 2008 to 265 billon in 2013 in pack numbers is expected. Selection of UHT and aseptic packaging systems reflect customer preferences and the processes are designed to ensure commercial sterility and acceptable sensory attributes throughout shelf life. Advantages of UHT processing include extended shelf life, lower energy costs, and the elimination of required refrigeration during storage and distribution. Desirable changes taking place during UHT processing of milk such as destruction of microorganisms and inactivation of enzymes occur, while undesirable effects such as browning, loss of nutrients, sedimentation, fat separation, cooked flavor also take place. Gelation of UHT milk during storage (age gelation) is a major factor limiting its shelf life. Significant factors that influence the onset of gelation include the nature of the heat treatment, proteolysis during storage, milk composition and quality, seasonal milk production factors, and storage temperature. This review is focused on the types of age gelation and the effect of plasmin activity on enzymatic gelation in UHT milk during a prolonged storage period. Measuring enzyme activity is a major concern to commercial producers, and many techniques, such as enzyme‐linked immunosorbent assay, spectrophotometery, high‐performance liquid chromatography, and so on, are available. Extension of shelf life of UHT milk can be achieved by deactivation of enzymes, by deploying low‐temperature inactivation at 55 °C for 60 min, innovative steam injection heating, membrane processing, and high‐pressure treatments.

The effect of gamma-irradiation on the antibacterial activity of honey.

There is increasing usage of honey as a dressing on infected wounds, burns and ulcers, but there is some concern that there may be a risk of wound botulism from the clostridial spores sometimes found in honey. It is well-established that the antibacterial activity is heat-labile so would be destroyed if honey were sterilized by autoclaving, but the effect of gamma-irradiation on the antibacterial activity of honey is not known. Therefore an investigation was carried out to assess the effect on the antibacterial activity of honey when the honey was subjected to a commercial sterilization procedure using gamma-irradiation (25 kGy). Two honeys with antibacterial activity due to enzymically-generated hydrogen peroxide and three manuka honeys with non-peroxide antibacterial activity were investigated. The honeys were tested against Staphylococcus aureus in an agar well diffusion assay. There was no significant change found in either type of antibacterial activity resulting from this form of sterilization of honey, even when the radiation was doubled (to 50 kGy). Testing of honey seeded with spores of Clostridium perfringens and C. tetani (10000 and 1000 spores g-1 of honey, respectively) showed that 25 kGy of gamma-irradiation was sufficient to achieve sterility.