Time-temperature Combinations Research Articles

Chemical kinetics and thermodynamics of PPO activity, colour changes and microbial degradation during blanching of the sugarcane billets.

Sugarcane juice, which has a short shelf life, is a popular thirst-quenching and rejuvenating beverage worldwide. The limited shelf life is a result of changes in polyphenol oxidase (PPO) activity, total plate count (TPC) and color attributes (L*, a* and b*-values). We hypothesized that chemical kinetics and thermodynamics of blanched sugarcane cane juice causing alterations in PPO, TPC, and L, a* and b*-values will address the challenges of sugarcane juice preservation. Sugarcane billets were blanched at variable time-temperature combinations in the range 0-20 min and 70-90 °C. Reaction rates increased with increasing temperature; PPO activity, TPC and colour followed first-order kinetics. PPO activity had an activation energy (Ea) of 81 kJ mol-1. The half life (t½) dropped from 16.5 to 3.47 min and decimal reduction time (D-values) dropped from 54.83 to 11.52 min. Thus reactions were temperature-sensitive. Thermodynamic studies indicated an endothermic (positive enthalpy values, ΔH > 0; 78.10 kJ mol-1) and reversible process (negative entropy values ΔS < 0; -0.044 kJmol-1 K-1). Michaeli-Menten constant (Km) and maximum velocity (Vmax) of PPO activity were determined by adding variable lemon juice concentrations in sugarcane juice. As the Km values increased (from 5.53 to 15.81 mm) and Vmax values decreased (from 666.67 to 384.61 UmL-1), a Lineweaver-Burk plot suggested decreased PPO affinity of sugarcane juice. The results of the present study indicate that studies on chemical kinetics and thermodynamics (PPO, TPC and L, a* and b*-values) of blanched sugarcane cane juice shall mitigate challenges of sugarcane juice preservation. © 2024 Society of Chemical Industry.

Effect of different sous-vide cooking temperature-time combinations on the functional and sensory properties of goose meat

The effect of goose meat sous-vide (SV) cooking at 6 combinations of temperature (60°C, 80°C) and time (4, 6, 12h) on selected functional properties was investigated. The study conducted an assessment of cooking loss (CL), moisture content, pH, longitudinal (LS), and transverse (TS) shrinkage, shear force (SF), texture profile analysis (TPA), color parameters (L*, a*, b*, C, h°), ΔE and carried out sensory evaluation. A total of 168 breast muscles (BM with and without skin) from 17-wk-old "Polish oat geese" were utilized. The CL was affected by both cooking temperature and time. The CL for meat with skin was higher than for without ones, and it was lower for both kinds of meat cooked at 60°C than at 80°C for all cooking times. The LS was higher than the TS. The higher shrinkage was stated for meat cooked at 80°C. There was a reduction in moisture content and slightly increasing pH by increasing temperature and prolonging cooking time. For both kinds of meat, the highest moisture retention was stated at 60°C/4h, and the lowest in samples heated at 80°C/12h. The samples cooked at 60°C were characterized by a higher L* value than those at 80°C. The a* values were higher for samples cooked at 60°C than those at 80°C, whereas b* were higher for meat cooked at 80°C. The SF exhibited a trend of lower values at 60°C compared to samples cooked at 80°C and it increased with prolonged cooking time. The value of hardness, cohesiveness, springiness, gumminess, and chewiness for meat cooked at 60°C increased, and for samples cooked at 80°C decreased with increasing cooking time. It was no significant differences in sensory scores for overall palatability for both kinds of meat cooked at 60°C and 80°C. Goose meat cooked at different time and temperature combinations showed extremely desirable overall palatability. Taking into account all discussed parameters, the optimal combination seems to be 60°C/4h.

Process Optimization for the Extraction of Phenolic Compounds from Pomegranate Peels: Response Surface Methodology-Desirability Function and Artificial Neural Network-Genetic Algorithm

Valorization of agricultural wastes is ongoing topic in industry. Determining the best conditions by artificial neural networks based optimization techniques is the key step to extract valuable compounds efficiently and to obtain high quality extracts. In this study, the response surface methodology (RSM)-desirability function (DF) and artificial neural network (ANN)-genetic algorithm (GA) approaches were compared in modeling and optimization the extraction parameters (temperature, time and ethanol concentration (ratio of ethanol to water, % v/v)) of phenolic compounds in pomegranate peels. The ANN-GA approach providing higher coefficient of determination and lower root mean square deviation showed better predictive capability than the RSM. The optimum time (81.4 min) and ethanol concentration (15.7%) of RSM-DF approach shifted to the lower levels (78.8 min and 15.3%) with the ANN-GA approach while the optimum temperature (54.0°C) shifted to a higher level (59.3°C). The use of these values provided total phenolic content of &gt;1000 mg GAE L-1 and the corresponding antioxidant activity was 11 mmol TE L-1. As a result, increasing temperature up to a critical level decreased the extraction time and ethanol concentration, and it was determined that higher time-temperature combinations must be used for the complete water-based extraction of phenolic compounds from plant wastes in comparison to ethanol-water based extraction.

Effect of different smoking times and temperatures on polycyclic aromatic hydrocarbon concentrations in smoked sausages

Smoked pork and chicken sausages were prepared using three different time-temperature combinations; 60 &amp;deg;C for 4 hours, 75 &amp;deg;C for 3 hours, and 90 &amp;deg;C for 2 hours. The amount of polycyclic aromatic hydrocarbons (PAHs) present in these smoked products was estimated using liquid chromatography-mass spectrometry (LC-MS). The PAH compounds were identified using multiple reaction monitoring (MRM) and the retention time of that particular compound. The most potent carcinogenic PAH compound, benzo(a)pyrene (BaP), was not detected in any of the treatments analyzed. The pork and chicken sausages were found to contain the following PAH compounds: Flu, BaA, Chr, BbF, and BkF. Chrysene was found in all samples in the range from 27.38 to 45.08 &amp;micro;g/kg. It was observed that a higher smoking temperature (90 &amp;deg;C) resulted in more PAH compounds in the sausages. Furthermore, the chicken sausages were found to have higher concentrations of PAHs, particularly Chr and BaA, than the pork sausages.

Steam explosion technology as a tool to alter the physicochemical properties of intermediate wheatgrass (Thinopyrum intermedium) bran

Products containing the perennial grain intermediate wheatgrass (IWG) have recently entered the market, but little is known about the effect of processing operations on its constituents. This study investigated the effect of steam explosion (SE) conditions, i.e., temperature (130, 150 or 170 °C) and residence time (5 or 10 min), spanning severity factors from 1.6 to 3.1, on physicochemical properties of IWG bran. Even the lowest temperature and shortest time combination (130 °C, 5 min), was sufficient to inactivate peroxidase, generally regarded as the most heat-stable enzyme in grains. Contents of free phenolic acids as well as water-extractable arabinoxylans significantly increased while phytic acid was reduced after SE. However, starch damage, free fatty acids as well as browning (all negatively affecting quality) increased with treatment severity. Thus, SE is a promising technology to reduce enzymatic activity, enhance phenolic and soluble fiber contents in IWG bran, but severity factors >2.5 may negatively affect quality.

Optimization of the Mechanical and Corrosion Resistance of Alloy 625 through Aging Treatments

In the as-annealed condition, the nickel-based Alloy 625 has excellent mechanical and corrosion properties compared to those of common stainless steels. This peculiarity enables its exploitation in several industrial fields at cryogenic and high temperatures and in the presence of severely corrosive atmospheres. However, in this alloy, when high-temperature plastic deformation processes and heat treatments are not carefully optimized, the occurrence of excessive grain coarsening can irremediably deteriorate the mechanical strength, possibly leading to incompatibility with the standard requirements. Therefore, this research work investigated the possibility of adopting single- and double-aging treatments aimed at improving such strength loss. Their optimization involved identifying the best compromise between the hardening effect and the loss in corrosion resistance induced by the simultaneous formation of intergranular chromium-rich carbides during aging. The investigation of the aging treatments was performed using hardness, tensile and intergranular corrosion tests considering different time–temperature combinations in a range from 621 °C to 732 °C. Double aging resulted in a considerable acceleration in the hardening response compared to single aging. However, even after its optimization in terms of both temperature and time, the intergranular corrosion resistance remained a critical aspect. Among all the tested conditions, only single aging at 621 °C for 72 h was acceptable in terms of both mechanical and corrosion properties. The influence of longer exposures will be investigated in a future study.

Determinant factors for berry derived anthocyanin persistency in stirred yoghurts

The development of healthy and functional ingredients has been limited because of their low stability under given environmental and processing conditions, anyhow the use of anthocyanin as a natural food colorant has been recognized through the last decades. Therefore, the main objective of this study is stabilizing the natural colour of stirred yogurts fortified with berry fruit pulps during the entire shelf life of the product by evaluating the factors that affect the stability of anthocyanins. Initially the effect of time-temperature combinations applied in processing fruit pulps was analyzed through 6 different treatments; 85 °C for 1 second, 85 °C for 20 minutes, 90 °C for 2 seconds, 90 °C for 20 minutes, 95 °C for 2 seconds, and 95 °C for 20 minutes. Besides, varying sugar levels (0 %, 20 %, 40 %, 60 %) incorporated fruit pulps, and six yoghurt bases composed with different ratios of Skimmed Milk Powder (SMP), modified starch and gelatin were tested against the color stability of the stirred yoghurt fortified with berry fruit pulps. The color variations in the stirred yoghurts were evaluated in terms of “L, a, b” values represented by the colorimeter. There was a significant (p<0.05) effect of berry fruit pulp processing time and temperature on the colour of the stirred yogurt and processing berry fruits at 95 °C for 20 minutes was identified as the most appropriate treatment to get an optimum colour in stirred yoghurt. Further analysis with varying sugar levels and different yoghurt bases revealed that, both factors are potential determinants that exert a significant effect on the color stability in stirred yoghurts throughout the shelf life. Interestingly, the L color value was greatly affected with varying quantities of sugar and there was no considerable effect of SMP level on the color properties of the yoghurt. However, the modified starch level emphasized an increase in all the three-color properties. Conclusively, the relationship between these determinant factors and the anthocyanin biochemistry should be further studied to obtain the therapeutic as well as industrial advantage of anthocyanin.

Experimental and simulation studies on blanching and its impact on the drying rate of carrot

AbstractThis paper presents an experimental and numerical study on the blanching and drying of carrots. Blanching of carrot slices has been performed at four temperature–time combinations. The effect of separating the core and cortex and blanching temperature on the drying rate of carrots has been studied. The blanching process increases the drying rate of carrots. The drying constant for slice, cortex, and core, respectively, has been found to be 22.84%, 24.90%, and 36.94% higher for the samples blanched at 95°C for 5 min, when compared to the unblanched samples. The drying rate also increases with the increase in blanching temperature. The drying constant increases by 37.64% and 109.18% in the case of cortex and core respectively, when compared to the slice. Temperature histories obtained through finite element analysis using ANSYS Fluent software were duly validated with the experiment.Practical applicationsThe effect of separating the core and cortex and blanching temperature on the drying rate of carrots has been studied in this paper. The blanching process increases the drying rate of carrots. The drying rate also increases with the increase in blanching temperature. Blanching further also helps to improve the drying constant. The separation of the cortex and core from the slice also aids in reducing drying time and increasing the drying constant. Thus, it has been concluded that the novel concept of separating the slice into core and cortex combined with blanching resulted in a very significant increase in drying rate which will result in a great saving of time and power input in the drying process.

Modelling inactivation kinetics of free and encapsulated probiotic cells in millet biscuit under different baking conditions

The rising popularity of probiotic food in the diet for improved health benefits leads to the development of new probiotic functional foods. In general, biscuit is a long-shelf-life snack product that can be consumed straight from the pack without further processing. Although the development of probiotic bakery products is an innovative approach to market expansion, the infusion of probiotics in biscuits to produce probiotic biscuits has not been explored because of the complexity of the baking process. Therefore, this study aimed to evaluate the impact of baking conditions (160, 180, 200, and 220 °C) on the viability of free and encapsulated probiotic Lactobacillus acidophilus NCDC 016 cells by adding them into biscuit dough separately and baking for up to 600 sec. The cells were encapsulated using 20 % maltodextrin and 8.51 % gum arabic as a wall material and spray drying at an inlet and outlet air temperature of 150 and 55 ± 2 °C, respectively. At different baking temperatures (160, 180, 200, and 220 °C), the viability of probiotic (free and encapsulated) cells, the physicochemical properties of biscuits, and the inactivation kinetics of cells were examined by withdrawing samples every 120 sec. The survivability of encapsulated cells was observed to be higher than free cells at 160 and 180 °C for 600 sec. The moisture content and water activity were found to be higher and lower, respectively for encapsulated probiotic biscuits than for the biscuit containing free cells. The observed results of higher cell viability at 200 °C, 360 sec (5.38 log CFU/g) than at 180 °C, 600 sec (5.02 log CFU/g) can be explained by the time–temperature combination. Thus, producing the probiotic biscuit at baking conditions of 200 °C and 360 min is possible, providing the cell viability of 5 log CFU/g of probiotic biscuit. Further, the inactivation kinetics of cells were predicted by log-linear, Weibull, log-logistic, Gompertz, and Buchanan models. Under all baking conditions, the log-linear model was the best model for describing the data of encapsulated and free cells.

Influence of hot water treatment on nutritional quality attributes of cold stored apple (Malus × domestica)

The present study was carried out at ICAR-Indian Agricultural Research Institute, New Delhi during 2021–2023 to study the effect of postharvest hot water treatment (HWT) on the nutritional quality attributes of apple [Malus × domestica Borkh.] cv. Royal Delicious. Apple fruits were exposed to hot water at 48, 50, 52 and 54°C for 2, 3, 4 and 5 min. Following the treatment, the fruits were cold stored (2±1°C, 90–95% relative humidity) for 90 days and evaluated for quality changes at every 15 days interval. Our results revealed that HWT of apple fruits at 48°C and 50°C were best for optimum retention of nutritional quality of apple fruits. Exposure of fruits to HWT at 48°C/5 min and 50°C/2 min resulted in least (0.73%, 0.75%) loss of ascorbic acid and anthocyanin content (0.10%, 0.21%), respectively as compared to other temperature-time combinations. At the end of a three month storage period, under control treatment, fruits exhibited 9.56% reduction of antioxidant (AOX) activity in comparison to 0.17–2.21% reduction in HWT apples. The maximum loss in quality attributes was noticed at highest temperature-time exposure (54°C/5 min). Thus, it was observed that the right combination of temperature and time for HWT is crucial to maintain fruit quality attributes without compromising nutritional value.

Relationship between Eimeria oocyst infectivity for chickens and in vitro excystation of E. acervulina, E. maxima, and E. tenella oocyst during long-term storage

Vaccination of chickens against avian coccidiosis in chickens often involves storing Eimeria oocysts for months after oocyst propagation and sporulation. The purpose of this study was to determine how long E. acervulina, E. maxima, and E. tenella oocysts remained viable when stored at refrigeration (4°C) or egg room (20°C) temperatures. Separate tubes containing E. acervulina, E. maxima, or E. tenella oocysts were stored at these temperatures and a sample removed every 3 mo for inoculating chickens for evidence of a patent infection. Also, an aliquot of each Eimeria species at each time-temperature combination was subjected to in vitro excystation to quantify the relative number of released sporozoites to intact (nonexcysted) sporocysts. Eimeria tenella appeared to be most susceptible to storage in that no oocyst production was observed at 9 mo at either temperature. Although E. maxima oocysts were viable at 9 mo, no oocyst production was observed at 12 mo storage at these 2 temperatures. Quite unexpected was that E. acervulina was much more stable than E. tenella and E. maxima remaining viable up to and including 27 mo at 4°C and up to and including 12 mo at 20°C. No consistent correlation was observed between in vivo oocyst production and in vitro excystation arising from these 2 respective temperatures (E. acervulina r=0.58, r=0.54; E. maxima r=0.90, r=0.54; E. tenella r=0.38, r=0.90). These data indicate that attention must be paid to time and temperature of Eimeria oocyst storage, and that sporozoite excystation may not be a good indicator of oocyst viability, particularly at later timepoints in incubation.

Electrical and Structural Properties of Chemically Deposited Photoconducting Films

In this study, we investigated the rise and decay of the chemically deposited quaternary metal sulfide thin films, which were deposited at different concentrations, temperatures, and deposition durations. On a glass substrate, films were deposited using a chemical bath deposition technique (CBD method). A graph plotted for the study of the rise and decay curves for these quaternary films was deposited. In addition to calculating the photocurrent and dark current values for the entire sample, the photoconductivity gain was also examined. There are reports and discussions about the X-ray diffraction pattern of our sample. The resulting films have thin-filmlike structures. This provides a unique outcome for photoconduction applications. Photoconducting gain ranges from 2.9 x 105 to 47.5 x 106are observed for various concentration, temperature, and deposition time combinations.

Effect of heat treatment on the quality of citrus juices

The current study was designed to estimate the effect of heat treatment conditions on the quality of the pomelo and kinnow juice. The different temperature–time combination was selected to treat the juices. The quality of the juice was determined based on TSS, acidity, ascorbic acid content, total phenolic content, reducing sugar, antioxidant activity, and sweetness. After the heat treatment to both the juice, the samples showed a significant decrease in total phenolic content, reducing sugars, ascorbic acidity and antioxidant activity of juices as the duration and temperature of the treatment increases. The acidity of the product increases, while sweetness decreases with an increase in the time of treatment. It was also found that there is no significant change in the properties with an increase in the temperature of treatment. It was revealed that low-temperature low time can be used to get a good final quality in terms of ascorbic acid, antioxidant, and total phenolic content of both juices.

Blanching effect on nutritionally important starch fractions of selected processing potato cultivars

Blanching is the primary treatment given to potato tubers before any other processing but has a differential impact on its starch content quality parameter. The present study aimed to evaluate the effect of three different blanching methods, i.e., water (100 °C for 5, 10, 15 min), steam (100 °C for 10, 15, 20 min) and microwave (640 W for 1, 3, 5 min) with different time-temperature combinations on nutritionally essential starch fractions of five potato processing cultivars (Kufri Chipsona 1, Kufri Chipsona 3, Kufri Chipsona 4, Kufri Himsona and Kufri Frysona). The total starch content in the raw samples ranged from 17.92 g/100 g to 69.27 g ̸ 100 g. All the blanching treatments caused a significant reduction of starch content, and 5 min water blanching treatment was standardized for optimum total starch content. Rapidly Digestible Starch content decreased as processing time was increased in all the treatments with maximum degradation by water blanching for 15 min. Slowly Digestible Starch content enhanced with an increase in processing time. The levels of the starch fractions varied depending on blanching methods. Blanching significantly influenced the various starch fractions in potatoes.

Effect of Sand Roasting on Physicochemical, Thermal, Functional, Antinutritional, and Sensory Properties of Sattu, a Nourishing form of Chickpea

Sattu is a traditional Indian food product made of chickpea with tremendous nutritional benefits. However, the processing of sattu has not been thoroughly explored which is an impediment to industrial applications involving the development of sattu-based products. These products carry immense benefits for consumers and for widespread popularity; it is essential that the roasting of sattu for further processing be investigated for improving the properties of sattu while reducing its antinutritional factors. In this study, the impact of sand roasting on the physicochemical, sensory, antinutritional, thermal, functional, and antioxidant properties on sattu was investigated. Chickpea grains were roasted in sand for different time periods (3–17 min) and temperature combinations (171–228°C). Results revealed that samples treated at 180°C for 15 min had maximum sensory score (3.99) followed by the samples treated at 200°C for 10 min and at 228°C for 10 min. Overall sattu roasted at 180°C for 15 min was found suitable for further application.

Enhanced heat tolerance of freeze-dried Enterococcus faecium NRRL B-2354 as valid Salmonella surrogate in low-moisture foods

In microbial studies of low-moisture foods (LMFs, water activity less than 0.85), freeze-dried bacteria benefit us to inoculate LMFs without introducing extra water or altering food physiochemical properties. However, the freeze-drying process would bring unavoidable damage to bacterial cells and results in less-resistant inoculum that are unlikely to be qualified in microbial studies. Herein, we enhanced bacterial heat tolerance by subjecting the cells to mild heat (42-50 °C) to counteract the reduced heat tolerance and survivability of freeze-dried bacteria. Enterococcus faecium NRRL B-2354 (E. faecium), a Salmonella surrogate in LMFs, was used as the target microorganism because it was widely accepted in microbial validation of thermal pasteurizing LMFs. Three types of LMFs (peanut powder, protein powder, and onion powder) were used as LMFs models to validate the freeze-dried E. faecium in comparison with Salmonella enterica Enteritidis PT 30 (S. Enteritidis) prepared by the traditional aqueous method. The heat tolerance (D65℃ value) of E. faecium increased at all treatments and peaked (+31.48 ± 0.13%) at temperature-time combinations of 45 °C-60 min and 50 °C-5 min. Survivability of freeze-dried inoculum and its heat tolerance retained well within 50 d storage. The freeze-dried E. faecium was prepared in this study brought equal or higher heat tolerance (D85℃ or D75℃) than S. Enteritidis in tested LMFs models. For instance, the D85℃ of freeze-dried E. faecium (heat-treated at 50 °C for 5 min) and S. Enteritidis in whole egg powder are 35.56 ± 1.52 min and 28.41 ± 0.41 min, respectively. The freeze-dried E. faecium with enhanced heat tolerance appears to be a suitable Salmonella surrogate for dry-inoculating LMFs. Our protocol also enables industry-scale production of freeze-dried inoculum by broth-cultivation method combined with mild-heat treatment.

Process optimization and evaluation of the effects of different time-temperature sous vide cooking on physicochemical, textural, and sensory characteristics of whiteleg shrimp (Litopenaeusvannamei)

The objective of the current study was to optimize the cook-chill conditions of high-value whiteleg shrimp (Litopenaeus vannamei) processed using the sous vide (SV) technique and to assess the effects of various time-temperature combinations on the physicochemical, textural, and sensory qualities. For optimization, a Response Surface Methodology (RSM) approach utilizing a Central Composite Design (CCD) was adopted. Optimum SV cooking conditions to acquire minimum texture (hardness) of 7235 g was 13.48 min and 81.87 °C, expressible moisture of 18.48% was 14.5 min and 84.5 °C, and cook loss of 5.58% was 5 min and 75 °C. Texture (hardness) and expressible moisture decreased while cooking loss increased with increasing time-temperature treatment. Redness and yellowness values increased (p < 0.05) with increasing SV cooking time-temperature, but lightness values were nearly consistent in all treatments. With increasing time and temperature, TBARs and total carotenoid content increased (p < 0.05). However, the TBARs values were within accepted limits and ranged from 0.05 to 0.08 mg malonaldehyde/kg. Sensory evaluation indicated that all SV cooked samples were well accepted, with overall scores ≥7. These results suggest that the SV cooking temperature and time had a substantial impact on the textural, physicochemical, and sensory characteristics of shrimp. In addition, increasing time-temperature increased cooking and moisture loss, but decreased hardness and higher sensory scores made the product more acceptable to consumers.

The Potential of Waste Phloem Fraction of Quercus cerris Bark in Biochar Production

Quercus cerris phloem is a lignocellulosic waste fraction obtained from bark fractionation. Biochars are technologically interesting functional materials that may be produced from lignocellulosic solid materials. This study explores the solid material properties of Quercus cerris phloem, evaluates biochar production from it, and explores its application as an adsorbent. In the first part of the study, thermogravimetric analysis, SEM microscopy observations, FT-IR spectroscopy, and ICP-AES analyses were performed on raw Quercus cerris phloem. In the second part of the study, biochars and activated carbons were produced and their structure, surface functional groups, methylene blue adsorption properties, and specific surface areas were determined. The results showed that Quercus cerris phloem is a lignocellulosic solid material that decomposes in a wide temperature range between 265 and 765 °C. The activation energy of phloem pyrolysis ranged between 82 and 172 kJ mol−1 in pyrolysis. The mineral composition is mainly calcium (88%) and potassium (4%). The biochar yield of Quercus cerris phloem ranged between 28% and 42% at different moderate temperature–time combinations. Raw phloem, phloem biochars, and phloem-activated carbons show high methylene blue removal efficiencies. Methylene blue adsorption follows pseudo-second-order kinetics. The BET surface areas of Quercus cerris phloem-activated carbons varied between 262.1 m2 g−1 and 317.5 m2 g−1.

Effect of heat treatment on microbiological safety of supermarket food waste as substrate for black soldier fly larvae (Hermetia illucens)

Supermarket food waste, constituting 13% of global food waste, can be upcycled as substrate for black soldier fly larvae (BSFL) and converted into larval biomass. Since presence of food pathogens in supermarket food waste is likely, microbiological safety should be ensured when using waste as insect substrate. Heat treatment provides a suitable pre-treatment to reduce microbiological contaminations. This study investigated the effect of different temperature–time combinations on the microbiological safety of supermarket food waste as BSFL substrate. Artificial supermarket food waste without meat and fish (SFW) was inoculated with both Salmonella and Staphylococcus aureus (7.0log cfu/g) and treated at 50 and 60 °C for 10, 20 and 30 min. While 50 °C was insufficient for adequate pathogen reduction, 60 °C only required 10 min to reduce the Enterobacteriaceae and S.aureus counts to < 1.0logcfu/g and for absence of Salmonella in 25 g. Heat-treated SFW could be stored for two days at ambient temperature or refrigerated without pathogen growth. Treatment of supermarket food waste containing meat and fish at 60 °C for 10 min caused similar results as for SFW, but S.aureus persisted (2.4logcfu/g), possibly by protective effects of fat and/or proteins. Finally, BSFL rearing experiments on SFW revealed significantly higher larval mass, bioconversion efficiency and waste reduction than on Gainesville diet, with no notable differences between untreated and heat-treated SFW. Rearing BSFL on supermarket food waste is possible, and unsafe food waste can be heated to obtain safety without eliminating nutrients necessary for rearing.

Impact of time-temperature combinations on the anti-Cytomegalovirus activity and biological components of human milk.

There is extensive evidence that Holder pasteurization (HoP) (30 min at 62.5 °C) has harmful effects on the bioactivities of human milk (HM). We previously demonstrated that lowering HoP temperature is sufficient to inactivate Cytomegalovirus (HCMV). Here, we analyzed the effect of lowering time/temperature on the antiviral activity against HCMV and IgA levels of HM. Eighty HM samples from five mothers were pasteurized in a range of temperature (62.5-56 °C) and time (40-10 min) in a conventional setting of Human Milk Bank. Unpasteurized HM from each mother was used as control. The samples were assayed against HCMV-AD169 strain in cell cultures and IgA levels were determined by ELISA. All HM samples exhibited anti-HCMV activity, to a different extent. An improvement of antiviral activity was observed in samples treated at 60, 58 and 56 °C compared to those at 62.5 °C, with ID50 values near those of unpasteurized milk. Similarly, better retention in IgA levels was observed by reducing the temperature of treatment. We demonstrated that a 2.5 °C reduction of heat treatment significantly preserved the IgA content and fully restored the anti-HCMV activity of HM, supporting this variant of HoP as a valid alternative to preserve HM bioactivities. This work questions the standard HoP and opens the debate on whether the pasteurization temperature commonly used in Human Milk Banks should be lowered to better preserve the biological components of the milk. A reduction of HoP temperature at 60 °C determined a significant preservation of anti-HCMV activity and IgA content of donor HM, compared to standard HoP. This alternative HoP is highly feasible compared to other substitute pasteurization techniques, since it would employ the same pasteurizer equipment found in most Human Milk Banks.