Come-up Time Research Articles

Novel Thermal Processing of Packaged Egg White Powder

Packaged egg white powder (PEWP) is traditionally processed in a hot room at 60°C for 14 days to enhance the safety and functionality. Thus, the traditional hot room processing method is too long and consumes more energy. In this study, continuous radiofrequency assisted thermal processing (CRFATP) of PEWP was investigated with an objective of determining the come-up times, evaluating heating uniformity, quality and functionality. The come-up times under radiofrequency heating (RFH) to increase the temperature of PEWP from 23°C to 90°C was 40 min, however, the temperature could not reach 90°C in hot air oven maintained at 93°C. Temperature increase inside the PEWP was slower in moving condition than that in the stationary condition. The maximum temperature difference among the locations within package in stationary and moving conditions was about 15°C. The coldest and hottest locations under stationery and moving conditions were different for RFH of the PEWP. Package processing of EWP with RF power not affected the color adversely. The foaming capacity of EWP at all the processing conditions except at CRFATP condition of 90°C for 16 h was not significantly different with that of the traditional processing condition. However, the processed PEWP at 90°C for 16 h lost its foaming property. Water holding capacity (WHC) of both the package processing conditions i.e., 80°C for 16 h and 90°C for 16 h have produced the gels of significantly higher WHC compared to that of the traditionally processed EWP. The functional properties of the EWP under batch mode processing and package mode processing were different at 90°C for 16 h. The study presented temperature profiles in PEWP which may be used to validate the physics-based models for packaged product processing and study may serve as a reference for PEWP processing.

Enhanced steam-sanitizer strategies for eliminating Listeria biofilms on food-contact surfaces

Food processing equipment contaminated with Listeria monocytogenes is a major cause of listeriosis outbreaks implicated in various fresh produce, highlighting the need for effective surface sanitization strategies to eliminate this pathogen from food-contact surfaces. This study evaluated the effectiveness of steam treatments at temperatures ranging from 100 to 142 °C, with or without chemical sanitizers, against Listeriainnocua (a surrogate for L. monocytogenes) biofilms on stainless steel (SS), polyester (PET), and rubber surfaces. Seven-day-old L. innocua biofilms on these surfaces were subjected to short-time steam treatments at 100, 125, and 142 °C, either alone or in combination with 10 ppm peroxyacetic acid (PAA) or quaternary ammonium compound (QAC). Culturable L.innocua cells were then detached and enumerated. Results showed that steam treatments exhibited quick killing efficacy during the come-up time (CUT, 8–12 s), regardless of steam temperatures or surface materials. For example, steam CUT at 100–142 °C led to reductions of culturable L. innocua by 3.0–4.2 log10 CFU/coupon on SS, 2.5–2.9 log10 CFU/coupon on PET, and 2.4–2.8 log10 CFU/coupon on rubber, respectively. However, killing rates decreased beyond the CUT and with extended steam exposure, showing more pronounced survival tails on PET and rubber compared to SS. To enhance the eradication of L. innocua biofilms, PAA or QAC at 10 ppm was applied for 1 min, followed by a short (CUT + 6 s) steam treatment at 125 °C, which resulted in ≥4.9 log10 CFU/coupon reductions of culturable L. innocua on all surfaces. Rubber surfaces showed the greatest resistance to these hurdle treatments compared to SS and PET. The findings from this study provide effective surface sanitization strategies for the food industry to control L. monocytogenes in processing facilities.

A novel micro ohmic heating cell for microorganism destruction kinetic studies: Performance validation

Ohmic heating cells used for microbial destruction are typically large compared with conventional capillary tubes. Limitations of commonly used large cells include large mass, high come-up-time (CUT), lack of uniform heating, and operation at atmospheric pressure. A new 3 mL Micro Ohmic Cell (MOC) was designed and fabricated for the kinetic study of microbial spore destruction. Two tiny titanium electrodes, mounted horizontally on a T-shaped cylindrical cell with a 3 cm gap, generate a rapid heating rate up to 140 °C. Fibre optic temperature sensors were used for direct temperature monitoring during CUT and holding time. Model solutions were heated under voltage gradients up to 90 V/cm. Uniform heating was achieved under stirring conditions with less than 1 °C variation across the cell volume, and the coldest spot was identified as the liquid-air interface. CUT was evaluated as influenced by both system and product parameters, resulting in less than 50 s comparable to those obtained using capillary tubes. The newly developed MOC was validated for microbial destruction kinetic study under ohmic heating conditions using Clostridium sporogenes spores in buffer and concentrated maple sap. With its small volume, short CUT, and uniform temperature similar to capillary tubes in conventional heating, the MOC has the potential to be considered as a standard device for kinetic studies under ohmic heating.

Utilizing superheated steam to inactivate Enterococcus faecium NRRL B-2354 on various material surfaces used in food and produce industries

Traditional sanitation in dry food and produce manufacturing plants is challenging as residual moisture can harbor microbial contamination. Superheated steam (SHS) is produced when water is heated to temperatures (125–400 °C) beyond the boiling point. SHS does not lead to condensation on surfaces. There are limited studies available on the sanitation efficacy of SHS on different surfaces. This study was conducted to understand the sanitation efficacy of SHS to inactivate Enterococcus faecium NRRL B-2354 on different surfaces (stainless steel, concrete, plywood, leather, polytetrafluoroethylene (PTFE), silicon rubber, cotton, and cardboard). The surfaces were either spot inoculated or coated with a representative food matrix (baby formula) and treated with SHS at 150 °C for a total process time (come-up time + treatment time) of 3 min. Spot-inoculated surfaces showed a higher microbial inactivation (range: 9.2 ± 0.9 to 10.7 ± 0.7 log reduction/coupon) whereas surfaces with inoculum coated with baby formula had lower microbial inactivation (range: 7.8 ± 0.4 to 9.6 ± 0.4 log reduction/coupon). The effects of surface characteristics like thermal inertia, surface roughness, and hydrophobicity of microbial inactivation were studied. Prolonged usage of SHS (150 °C for 5 min once a week over 8 weeks) did not alter surface characteristics, particularly roughness of stainless steel, silicone rubber and plywood.

Use of Flexible Retort Pouch as a Packaging Alternative for Three Mexican Ready-to-eat Bean Products

Objective: This study aimed to design a thermal process for three Mexican bean products packaged on flexible retort pouches and to compare the changes in quality, proximate composition, and antioxidant activity. Method: Three Mexican bean products: “pork beans” (PB), refried beans (RB), and mixed beans (MB, 50% “pork beans” and 50% refried beans), were packaged in retort pouches and processed in a steam/air retort at temperature 122°C, pressure = 2.6 kg·cm-2, come-up time = 13.5 min and 40 min of process, under overpressure conditions. Additionally, nine samples of each bean product packaged in plastic containers of 500 mL were added from the manufacturer's regular hot-fill processing line to be analyzed as control tests. Parameters of quality in all the products were evaluated. Research results and discussions: The Fo values were 13.2, 13.5, and 11.3 min for PB, RB, and MB, respectively. The beans thermally processed showed better protein, fiber, total phenolic, and essential minerals than traditional treatment, were viable, and did not need refrigerated storage. Research implications: The study of thermal processes in heat-resistant pouches in three types of ready-to-eat beans is a healthy and nutritious food alternative. Originality/Value: This study contributes to the development of sterilized foods safe by adjusting the temperature and process time to a Fo value that guarantees the destruction of Clostridium botulinum, with less impact on the final quality of the processed food.

Effect of microwave treatment for wine microbial stabilisation: Potential use of a Weibullian mathematical model

The aim of this research was to investigate the efficiency of microwaves (MW) for wine microbiological stabilization and thereby assess the potential application of a Weibullian mathematical model in wine industry. The study focused on (i) the influence of treatment time (come-up time and temperature maintenance) and temperature on a simple wine-like matrix, as well as (ii) the specific resistance of yeast and bacteria selected according to their representativeness in red wines (A. aceti ATCC_15973, S. cerevisiae FX10, B. bruxellensis CRBO_L0619 and AWRI_1499), and finally (iii) the potential usefulness of a new mathematical model adapted to heat treatment to evaluate strain sensitivity. This research aimed to show that microwave treatment decreases the main wine-associated microorganism populations and that the reduction in viable counts mainly depends on the MW treatment temperature. Complete microbiological stabilisation was obtained under a temperature of 50 °C a very short treatment time, except in the case of A. aceti ATCC_15973. Furthermore, the Weibull parameters analyses showed that heat inactivation a wine microorganism studied did not follow first-order kinetics, indicating that we should change our way of studying thermal death curves. The findings from this study suggest that MW could be useful for the wine industry as a complement or an alternative to sulphite utilisation.

Inactivation of Lactobacillus brevis cells and Bacillus cereus spores as influenced by pressure, shear, thermal, and valve geometry

ABSTRACT This study investigated the influence of pressure, shear, temperature, and their interactions on the inactivation of two bacteria – Lactobacillus brevis and Bacillus cereus spores. Cell suspension of L. brevis (1.6 × 1010 CFU/mL) and spore suspension of B. cereus (3.2 × 108 CFU/mL) were suspended in HEPES buffer (pH 7.3) and subjected to ultra-shear treatment (UST) at 400 MPa, process temperatures of 40 and 70°C, and flow rate of 0.0012 ± 0.0003 kg/s. In separate equipment, thermal (0.1 MPa-70°C-0/5 min) and high-pressure processing (HPP-400 MPa-40°C and 70°C-0/5 min) experiments were carried out to evaluate thermal only, pressure only, and combined pressure-thermal effects. Pressure-only treatment at 400 MPa for 0 min (come-up time) at 70°C resulted in 8.4 and 2.3 log reductions of L. brevis cells and B. cereus spores, respectively. After UST treatment at 70°C, L. brevis and B. cereus spores were reduced by 7.1 and 1.6 logs, respectively. Both strains showed different sensitivities to thermal, pressure, shear, and their combinations. B. cereus spores were relatively more resistant to HPP and UST treatments. Three valve geometries, namely, ultra-shear valve, needle valve, and tubular valve, were used to compare UST treatment effect on L. brevis and B. cereus spores at 40 and 70°C. UST treatment using the ultra-shear valve produced inactivation of 2.0 and 7.1 log cycles for L. brevis during 40 and 70°C process temperatures, respectively, which was relatively higher than needle valve and tubular valve. This higher inactivation could be attributed to the smaller valve gap and higher shear rate in the ultra-shear valve. Further, the comparatively higher inactivation at 70°C UST (7.1 log) emphasized the role of temperature on inactivation during UST. For both L. brevis and B. cereus, the inactivation was least in the tubular valve with relatively lesser shear rate, which indicated the desirable contribution of high shear rate for microbial inactivation. The information from this study contributes to the development of safe harbor UST process conditions for liquid foods.

Ready-To-Eat Rice in Retort Pouch Packaging as an Alternative Emergency Food Product

Recently, the rising incidence of natural catastrophe has increased the disaster preparedness, aiming to mitigate its devastating effect. Developing an emergency food is one of meaningful attempts to rise the preparedness. This research aimed to determine the best formula of ready-to-eat rice in retort pouch packaging accepted by consumers, and to determine the operating time to reach a lethality value (F0) to meet the commercial shelf-stable food requirements as an emergency food. The thermal process adequacy (F0) was used to determine the commercial shelf-stable products according to Indonesian regulation. The results showed that the determination of ready-to-eat rice was dependent on the ratio of rice and water. The most accepted product was determined according to quality attributes and organoleptic tests applied to meet the criteria for emergency food, namely color, flavor, and texture and best perceived by consumers. A formula with 140 g of half-cooked rice and 60 g of water was attributed to the best sample, having hardness of 7305.45 gf, elasticity of 36.40%, gumminess of 2185.720 gf, and adhesiveness of -167.975 g.s. In terms of microbiological quality, the TPC for the half-cooked rice sample reached 7.2×107 CFU/mL, while cooked rice in retort pouch packaging was <25 CFU/mL. Using heat distribution curve, heating at 110°C produced a come up time (CUT) after 40 min. Furthermore, the F0 value was 4.12 which was in accordance with the Indonesian regulation.

Microscopical Evaluation of the Effects of High-Pressure Processing on Milk Casein Micelles.

The effect of different high-pressure processing (HPP) treatments on casein micelles was analyzed through scanning electron microscopy (SEM) and a particle size distribution analysis. Raw whole and skim milk samples were subjected to HPP treatments at 400, 500 and 600 MPa for Come-Up Times (CUT) up to 15 min at ambient temperature. Three different phenomena were observed in the casein micelles: fragmentation, alterations to shape and agglomeration. The particle size distribution analysis determined that, as pressure and time treatment increased, the three phenomena intensified. First, the size of the casein micelles began to decrease as their fragmentation occurred. Subsequently, the casein micelles lost roundness, and their shape deformed. Finally, in the most intense treatments (higher pressures and/or longer times), the micelles fragments began to agglomerate, which resulted in an increase in their average diameter. Homogenization and defatting had no significant effect on the casein micelles; however, the presence of fat in whole milk samples was bioprotective, as the effects of the three phenomena appeared faster in treated skim milk samples. Through this study, it was concluded that the size and structure of casein micelles are greatly altered during high-pressure treatment. These results provide information that broadens the understanding of the changes induced on casein micelles by high-pressure treatments at room temperature.

Design of a batch Ohmic heater and evaluating the influence of different treatment conditions on quality attributes of kinnow (Citrus nobilis × Citrus deliciosa) juice

A batch Ohmic heater (5 L) with a modified electrode arrangement was designed for quick and uniform heating of kinnow juice. A T-shaped arrangement and micro silver coating over stainless steel electrodes provided temperature variation of 0–2 °C across the system and a system performance coefficient of 0.96. The come-up time for 60–80 °C was 1.3–3 min at 180 V. Pectin methylesterase, the most resistant enzyme, was inactivated completely at (120 V/80 °C/1 min), (150 V/80 °C/30 s), (180 V/70 °C/10 s). No aerobic mesophiles, yeasts, and moulds were detected in these samples. Ohmic heating at 180 V did not influence the colour of the juice significantly; however, some samples showed a little elevation (by 0.2) in the pH. The reduction in vitamin C, antioxidants, and total phenols was 6–12% at 150 V/80 °C/30 s. The fuzzy analysis shows that the Ohmic pasteurized juice had the highest similarity score. Industrial relevancesA batch assembly (5 L capacity) of the Ohmic heater has been fabricated to make a shelf-stable kinnow juice. The produced juice is microbially safe, enzymatically stable, and retains maximum bioactive compared to conventional thermal treatment. Thus, Ohmic heated juice can fulfill the stakeholders' demand for microbial safety, enzymatic stability, and nutritional superiority. Industry can scale up the design of batch Ohmic heater for efficient and faster pasteurization of citrus juice like kinnow juice.

Sterilizing Ready-to-Eat Poached Spicy Pork Slices Using a New Device: Combined Radio Frequency Energy and Superheated Water.

In this study, a new device was used to inactivate G. stearothermophilus spores in ready-to-eat (RTE) poached spicy pork slices (PSPS) applying radio frequency (RF) energy (27.12 MHz, 6 kW) and superheated water (SW) simultaneously. The cold spot in the PSPS sample was determined. The effects of electrode gap and SW temperature on heating rate, spore inactivation, physiochemical properties (water loss, texture, and oxidation), sensory properties, and SEM of samples were investigated. The cold spot lies in the geometric center of the soup. The heating rate increased with increasing electrode gap and hit a peak under 190 mm. Radio frequency combined superheated water (RFSW) sterilization greatly decreased the come-up time (CUT) compared with SW sterilization, and a 5 log reduction in G. stearothermophilus spores was achieved. RFSW sterilization under 170 mm electrode gap reduced the water loss, thermal damage of texture, oxidation, and tissues and cells of the sample, and kept a better sensory evaluation. RFSW sterilization has great potential in solid or semisolid food processing engineering.

Ohmic Heating Extraction at Different Times, Temperatures, Voltages, and Frequencies: A New Energy-Saving Technique for Pineapple Core Valorization.

Pineapple core is considered a processing by-product. This study proposed and evaluated an ohmic heating extraction-based valorization platform to obtain value-added bioactive compounds from pineapple core and studied the effects of four important processing parameters. In this sense, a Taguchi design (L16(4)4) was used to assess the effects of temperature (70, 80, 90, and 100 °C), time (15, 30, 45, and 60 min), voltage (110, 160, 210, and 260 V), and frequency (60, 340, 620, and 900 Hz) on heating rate, come-up time, energy consumption, system performance efficiency, total phenolic compounds (TPC), DPPH, and ABTS. Finally, a side-by-side comparison of optimized ohmic heating (OOH) and conventional extraction was performed, and chemical composition was compared by ultra-performance liquid chromatography equipped with photodiode array detection-mass (UPLC-DAD-ESI-MS-MS). According to the results, increasing temperatures enhanced system performance efficiency but negatively affected TPC and antioxidant values above 90 ℃. Similarly, prolonging the extraction (>30 min) decreased TPC. Further, increasing voltage (from 110 to 260 V) shortened the come-up time (from 35.75 to 5.16 min) and increased the heating rate (from 2.71 to 18.80 °C/min−1). The optimal conditions were 30 min of extraction at 80 °C, 160 V, and 900 Hz. Verification of the optimal conditions revealed that OOH yielded an extract with valuable bioactive compounds and saved 50% of the time and 80% of energy compared to the conventional treatment. The UPLC-DAD-ESI-MS-MS showed that there were similarities between the chemical profiles of the extracts obtained by conventional and OOH methods, while the concentration of major compounds varied depending on the extraction method. This information can help achieve sustainable development goals (SDGs) by maximizing the yield and minimizing energy and time consumption.

Ohmic vs. conventional heating: Influence of moderate electric fields on properties of egg white protein gels

The present study investigates properties of heat-induced, self-standing gels of globular proteins. Native egg white protein (EWP) with 9,8 wt% protein and 0,395 wt% NaCl content was adjusted to pH = 7,0 and heated from 25 to 85 °C via Ohmic heating (OH) and conventional heating (COV) with respective come-up times (CUT, 240 and 1200 s) and holding times (HOLD, 30 and 900 s). Gels heated under OH showed lower denaturation levels and less water holding capacity. When HOLD was short, the firmness of OH gels exceeded COV gel firmness but deceeded at long HOLD. Similarly, at short HOLD OH samples presented higher hydrophobic interactions whereas at long HOLD COV gels showed more hydrophobic interactions. This correlated with changes of intermolecular beta-sheet structures which increased with HOLD at COV but decreased or remained unchanged during OH. Furthermore, as an SDS-PAGE revealed the main EWP, ovalbumin, did not fully denature when heated via OH, this lead to the assumption that the oscillatory electric field partially interferes the complete denaturation and development of intermolecular beta-sheet structures and hydrophobic interactions during thermal gelation of this protein. Scanning electron microscopy also showed deviances in network structures between OH and COV as COV gels exhibited a denser and OH gels a more open and porous network structure.

A Case-study: Temperature Distribution and Heat Penetration in Steam-air Retort, Using Glass Jars and Retort Pouches

Abstract Retort thermal sterilization of canned food is a technology, which allows preserving food products by applying heat on packaged food in retorts (autoclaves) at temperatures up to 121 °C. The thermodynamics of the processes in the retort are influenced by the product stacking method in the basket and packaging material. The aims of this study were: 1) to analyse and compare temperature distribution (TD) and the slowest to heat location in the steam-air retort stacked with glass jars and with retort pouches; 2) to analyse and compare commercial product heat penetration (HP) characteristics in glass jars and retort pouches. Temperature measurements were performed with wireless thermocouples. The come-up time (heating phase) required to achieve in the retort temperature uniformity criteria of ±0.5 °C, is 28 min when the retort is stacked with glass jars, and 24 min when the retort is stacked with retort pouches. Total calculated process time (holding phase), necessary to achieve the sterilization value (F0 of 3 min), for sample in glass jars was 67 min, but in retort pouches – 62 min. The overall sterilization process time difference between two considered packaging types was 9 min, which is significant amount of time in the context of commercial processing. The study clearly shows the necessity to perform the Temperature Distribution and Heat Penetration study, as each packaging material, stacking method and product will affect sterilization process thermodynamics and, therefore, the overall process time and consequently - the safety of food product.

Effect of High Hydrostatic Pressure on the Extractability and Bioaccessibility of Carotenoids and Their Esters from Papaya (Carica papaya L.) and Its Impact on Tissue Microstructure.

High hydrostatic pressure (HHP) is a non-thermal technology widely used in the industry to extend food shelf-life and it has been proven to enhance the extractability of secondary metabolites, such as carotenoids, in plant foods. In this study, fresh-cut papaya pulp of varieties (Sweet Mary, Alicia and Eksotika) from the Canary Islands (Spain) were submitted to the HHP process (pressure: 100, 350 and 600 MPa; time: come-up time (CUT) and 5 min) to evaluate, for the first time, individual carotenoid and carotenoid ester extractability and to assess their bioaccessibility using an in vitro simulated gastrointestinal digestion assay, following the standardized INFOGEST® methodology. In addition, changes in papaya pulp microstructure after HHP treatments and during the different phases of the in vitro digestion were evaluated with optical light microscopy. HPLC-DAD (LC-MS/MS (APCI+)) analyses revealed that HHP treatments increased the carotenoid content, obtaining the highest extractability in pulp of the Sweet Mary papaya variety treated at 350 MPa during 5 min (4469 ± 124 μg/100 g fresh weight) which was an increase of 269% in respect to the HHP-untreated control sample. The highest carotenoid extraction value within each papaya variety among all HHP treatments was observed for (all-E)-lycopene, in a range of 98–1302 μg/100 g fresh weight (23–344%). Light micrographs of HHP-treated pulps showed many microstructural changes associated to carotenoid release related to the observed increase in their content. Carotenoids and carotenoid esters of papaya pulp submitted to in vitro digestion showed great stability; however, their bioaccessibility was very low due to the low content of fatty acids in papaya pulp necessary for the micellarization process. Further studies will be required to improve papaya carotenoid and carotenoid ester bioaccessibility.

Bioaccessibility of Antioxidants in Prickly Pear Fruits Treated with High Hydrostatic Pressure: An Application for Healthier Foods.

High hydrostatic pressure (HHP) is a commercial processing technology which can enhance the health potential of foods by improving the bioaccessibility of their bioactive compounds. Our aim was to study the bioaccessibility and digestive stability of phenolic compounds and betalains in prickly pear fruits (Opuntia ficus-indica L. Mill. var. Pelota and Sanguinos) treated with HHP (100, 350, and 600 MPa; come-up time and 5 min). The effects of HHP on pulps (edible fraction) and peels (sources of potential healthy ingredients) were assessed. In pulps, betanin bioaccessibility increased (+47% to +64%) when treated at 350 MPa/5 min. In HHP-treated pulps, increases in the bioaccessibility of piscidic acid (+67% to +176%) and 4-hydroxybenzoic acid glycoside (+126% to 136%) were also observed. Isorhamnetin glycosides in peels treated at 600 MPa/CUT had higher bioaccessibility (+17% to +126%) than their controls. The effects of HHP on the bioaccessibility of health-promoting compounds are not exclusively governed by extractability increases of antioxidants in the food matrix (direct effects). In this work we found evidence that indirect effects (effects on the food matrix) could also play a role in the increased bioaccessibility of antioxidants in fruits treated with HHP.

Inactivation of Zygosaccharomyces rouxii in organic intermediate moisture apricot and fig by microwave pasteurization

Zygosaccharomyces rouxii is an osmotolerant yeast that is responsible for the spoilage of high sugar content foods. Microwave heating technology is used as an alternative to conventional pasteurization. Main purpose of this research was to determine the thermal resistance of Z. rouxii in organic intermediate moisture content (IMC) fruits (apricot and fig) during the microwave pasteurization process and comparing the D, z and F values with the conventional method. F85 values were calculated both theoretically and experimentally. Additionally, the effects of the pasteurization methods on the quality properties (total soluble solid, pH, acidity, water activity, moisture content, rehydration capacity, weight loss, hydroxymethylfurfural (HMF) and color) of the samples were investigated. The results show that come up time (CUT) and D values were significantly reduced by microwave treatment. The yeast reached a five log10 reduction by the microwave heating method with the F8533.8 value of 3.6 min for apricot and F8532.15 value of 3.35 min for fig. Total soluble solids, weight loss, and color values were preserved better in microwave pasteurization than the conventional method in both samples. Hydroxymethylfurfural content of the microwave pasteurized samples was 23.5% and 32% less than the samples pasteurized conventionally for apricot and fig samples, respectively.

Heating of milk powders at low water activity to 95°C for 15 minutes using hot air-assisted radio frequency processing achieved pasteurization

Salmonella persistence in milk powders has caused several multistate foodborne disease outbreaks. Therefore, ways to deliver effective thermal treatment need to be identified and validated to ensure the microbial safety of milk powders. In this study, a process of hot air-assisted radio frequency (HARF) followed by holding at high temperatures in a convective oven was developed for pasteurization of milk powders. Heating times were compared between HARF and a convection oven for heating milk powders to a pasteurization temperature, and HARF has been shown to considerably reduce the come-up time. Whole milk powder (WMP) and nonfat dry milk (NFDM) were inoculated with a 5-serotype Salmonella cocktail and equilibrated to a water activity of 0.10 to simulate the worst case for the microbial challenge study. After heating the sample to 95°C using HARF, followed by 10 and 15 min of holding in the oven, more than 5 log reduction of Salmonella was achieved in WMP and NFDM. This study validated a HARF-assisted thermal process for pasteurization of milk powder based on previously collected microbial inactivation kinetics data and provides valuable insights to process developers to ensure microbial safety of milk powder. This HARF process may be implemented in the dairy industry to enhance the microbial safety of milk powders.

The impact of emerging domestic and commercial electro-heating technologies on energy consumption and quality parameters of cooked beef

The purpose of this study was to investigate the effects of e-Cooker® and moderate electric field (MEF) cooking on physical and chemical changes occurring during the cooking of meat. Beef muscle samples (38.86 ± 0.08 g) were cooked in saline solution (0.5% w/w NaCl) to a target temperature of 72 °C, followed by a 2 min holding time. The experimental results revealed that e-Cooker® and MEF significantly reduced the come-up time required to achieve a target temperature of 72 °C to 1.16 ± 0.02 min and 0.86 ± 0.02 min, respectively compared to 14.12 ± 0.55 min in conventional cooking. The colour and instrumental texture of cooked meat by e-Cooker® and MEF systems were not significantly different (P > 0.05) from conventionally cooked ones. Overall, the results obtained demonstrated that e-Cooker® and MEF can be used to cook meat in a shorter time and reasonably low energy input while producing a product which is comparable in quality to conventionally cooked meat.

Aichi virus inactivation by heat in 2‐ml glass vials

Aichi virus (AiV) that results in gastroenteritis worldwide, is spread through contaminated shellfish and water. The resistance/tolerance of AiV to common inactivation processes along with the absence of commercially available vaccines makes it necessary to study its thermal inactivation kinetics. This research evaluated the heat inactivation of AiV in cell-culture media using 2-ml sterile glass vials by the linear and Weibull models. Heat treatments of AiV titers of 7 log plaque forming units (PFU)/ml were conducted thrice in a water-bath at 50, 54, and 58 °C for up to 90 min. Plaque assays for each dilution in duplicate were used to determine infectious virus titers. Linear model D-values for AiV at 50 ± 1 °C (± = standard error) (come-up time = 68 s), 54 ± 0.7 °C (130 s), and 58 ± 0.6°C (251 s) were 43.3 ± 4.23 (R2 = 0.40, RMSE = 0.56), 5.69 ± 0.28 (R2 = 0.80, RMSE = 0.43), and 1.20 ± 0.63 min (R2 = 0.69, RMSE = 0.39), respectively, and the linear model z-value was 5.14 ± 0.39°C (R2 = 0.99, RMSE = 0.08). For the same temperatures, the Weibull model td = 1 values were 20.98 ± 8.8 (R2 = 0.62, RMSE = 0.46, α (scale parameter) = 2.30, β (shape parameter) = 0.38), 3.84 ± 0.69 (R2 = 0.85, RMSE = 0.38, α = 1.08, β = 0.66), and 0.87 ± 0.10 min (R2 = 0.80, RMSE = 0.32, α = 0.22, β = 0.61), respectively and the z-value (using Td = 1 ) was 5.79 ± 0.22 °C (R2 = 1.0, RMSE = 0.03). A better fit was obtained with the Weibull model for log reductions versus time with higher R2 and lower RMSE values. Application of AiV inactivation parameters can help reduce the risk of AiV outbreaks.