Chemical Preservation Research Articles

Recent advances in processing and preservation of minimally processed fruits and vegetables: A review – Part 1: Fundamentals and chemical methods

The mechanical damage caused by minimal processing drastically reduces the shelf life of fruits and vegetables, making them more susceptible to microbial contamination, nutritional, and sensory changes. Maintaining the quality of minimally processed products during storage necessarily depends on the use of preservation technologies, whether applied through physical or chemical methods or their combination. In the first part of this review, some fundamentals of minimal processing steps are detailed, which include the implications on the respiratory metabolism, ethylene biosynthesis and action, appearance, texture, aroma, flavor, water loss, and microbiological safety of these products. Furthermore, the advantages, disadvantages, and applications of the main chemical preservation methods in minimally processed fruits and vegetables are explored. The challenge of this work was to provide the scientific foundation for food producers and processors to identify the most suitable and effective preservation method for a variety of minimally processed fruits and vegetables. Novelty impact statement Preharvest factors have a significant impact on product quality and shelf life. QACs, hydrogen peroxide and ozone are potential alternatives to the use of chlorine. Potential applications of antibrowning and antisoftening agents were highlighted.

Fixation and preservation contribute to distortion in vertebrate museum specimens: a 10-year study with the lizardAnolis sagrei

AbstractPreservation of museum specimens depends on chemical fixation and preservation, processes that might distort the original material. Relatively few studies have examined the effects of preservation in potentially susceptible soft-bodied taxa, such as herpetofauna, and those that have rarely extend over more than a few months. We collected six common morphological measurements from the same set of radiographed specimens of the Neotropical lizard Anolis sagrei over nearly 10 years to investigate whether morphometric changes result from fixation in formalin and/or subsequent long-term preservation in ethanol. Snout–vent length declined by 3.5% on average over 10 years, starting almost immediately with fixation and continuing to decline during fluid preservation, eventually levelling off at 40 weeks and beyond. The mostly ossified component of snout–vent length, spine length, declined by 2% on average, but the decline did not begin until fluid preservation commenced and continued throughout the duration of the study. Other characters showed significant decline over the course of the study. Our findings suggest caution when combining fresh and preserved specimens or specimens of different preservation ages, because a decline in snout–vent length but not in other allometrically proportional characters will introduce error when correcting characters for body size in preserved animals.

Application of Biotechnology in Specific Spoilage Organisms of Aquatic Products.

Aquatic products are delicious and have high nutritive value, however, they are highly perishable during storage due to the growth and metabolism of microorganisms. The spoilage process of aquatic products was demonstrated to be highly related to the composition of microorganisms, in which the specific spoilage organisms (SSOs) are the main factors. In this article, the spoilage indicators of SSOs were systematically described, which could make a comprehensive evaluation of the quality of aquatic products. Quorum sensing (QS) regulates the growth, metabolism and characteristics of SSOs, the common signaling molecules and the QS system in the major SSOs of aquatic products were discussed. Moreover, we compared various technologies for the analysis of SSOs in aquatic products. Besides, quality control techniques based on microbiota regulating of aquatic products, including physical, chemical and biological preservation strategies, were also compared. In conclusion, novel preservation technologies and hurdle techniques are expected to achieve comprehensive inhibition of SSOs.

Effect of physical and chemical preservation techniques on nutritional, morphological, phenolic and antioxidant profile of Dendrocalamus hamiltonii sprouts

Effect of physical and chemical preservation techniques on nutritional, morphological, phenolic and antioxidant profile of Dendrocalamus hamiltonii sprouts

Biopolymer Production from Organic Wastes

Presents a possibility of reducing the technological cycle of biopolymer production from organic wastes of leather and fur industries by 2.2 times vs. known methods by optimizing raw material pre-preparation for dissolution. The accelerated method of biopolymer production makes possible its physical and chemical properties preservation, increase its clean content increase, as well as reduce wastewater pollution by sodium hydroxide and sulfide, water consumption, wastewater disposal, materials and electricity consumption for its production.

Validation and Uncertainty Evaluation of an LC-DAD Method for Simultaneous Quantification of Benzoic Acid, Methylparaben, and N-Butylparaben in Soy Sauce

Chemical food preservation is the common strategy used by human to preserve the natural properties and to increase the shelf life of food. Although preservatives are useful to keep the food fresh and to stop the bacterial growth, there are certain preservatives that are harmful if taken in more than the prescribed limits. Some of the typical used—benzoic acid, methylparaben, and n-butylparaben—were employed in this work with the aim of establishing a simultaneous liquid chromatography (LC) method for detecting each in soy sauce matrices. Liquid and C18 solid phase extraction were performed in this procedure prior to LC using Diode Array Detector analysis. In gradient elution of a format buffer (pH 4.4) and acidified acetonitrile, the target components were successfully separated. Calibration curve ranged from 0.61–140 mg/kg linearly while the limit of quantification for benzoic acid, methylparaben, and n-butylparaben were 0.41, 0.10, and 0.11 mg/kg, respectively. The intermediate precision and recovery were in the range between 0.15-1.89% and 100.5-103.3%, respectively. The expanded uncertainty (k=2) in sample measurement was estimated at 3.4-6.5%. The offered method was conformed to the validation acceptance criteria and can be applied as a routine method in the laboratory at ppm level.

Possible Ribose Synthesis in Carbonaceous Planetesimals.

The origin of life might be sparked by the polymerization of the first RNA molecules in Darwinian ponds during wet-dry cycles. The key life-building block ribose was found in carbonaceous chondrites. Its exogenous delivery onto the Hadean Earth could be a crucial step toward the emergence of the RNA world. Here, we investigate the formation of ribose through a simplified version of the formose reaction inside carbonaceous chondrite parent bodies. Following up on our previous studies regarding nucleobases with the same coupled physico-chemical model, we calculate the abundance of ribose within planetesimals of different sizes and heating histories. We perform laboratory experiments using catalysts present in carbonaceous chondrites to infer the yield of ribose among all pentoses (5Cs) forming during the formose reaction. These laboratory yields are used to tune our theoretical model that can only predict the total abundance of 5Cs. We found that the calculated abundances of ribose were similar to the ones measured in carbonaceous chondrites. We discuss the possibilities of chemical decomposition and preservation of ribose and derived constraints on time and location in planetesimals. In conclusion, the aqueous formose reaction might produce most of the ribose in carbonaceous chondrites. Together with our previous studies on nucleobases, we found that life-building blocks of the RNA world could be synthesized inside parent bodies and later delivered onto the early Earth.

Khoa and khoa based traditional dairy products: preparation, spoilage and shelf life extension.

Khoa and khoa based products (burfi, peda, kalakand, milk cake, etc.) are a category of traditional dairy products of Indian subcontinent. They are prepared by open pan desiccation along with stirring and scraping of milk to the desired consistency, followed by addition of sugar and / or colour and flavoring ingredients. The peculiar sensory attributes developed during their course of preparation makes them unique, but their short shelf-life is a major challenge faced by the dairy industries. They are spoiled mainly because of yeast and mold growth along with detrimental changes in the sensory attributes. This review describes various preservation techniques explored in the last two decades such as packaging interventions, modified atmospheric and active packaging, chemical preservation, water activity modification, natural preservation, thermal treatments, bio-preservation, etc. which can be used either singly or in combination (hurdle technology), to enhance the shelf life of these milk products.

Experimental investigation of different-shaped microwave-heated potatoes: thermal and quality characteristics analysis for food preservation.

Food materials are consumed for nutritional purposes in the form of fruits, vegetables, plants, and meat. These contain proteins, carbohydrates, and other useful nutritional compounds and these processed foods are a rich source of nutrition. The demand and supply of hygienic food for a particular population is possible only by food preservation. It can be done by various methods such as drying, freezing, chilling, chemical preservation, and pasteurization. Drying is a method of food preservation and it can be done by solar drying, microwave heating, vacuum drying, and some other methods. Microwave heating is a fast-drying method. It utilizes electrical energy to generate heat energy. The domestic microwave oven is not harmful but a commercial-level oven may be little bit harmful, when operated on high frequency. Potato is used as a sample material with different shapes such as slab, cylindrical, and spherical. The microwave oven has been operated at four different microwave powers such as 100W, 300W, 600W, and 800W. Slab-shaped (30°C), cylindrical-shaped (31.5°C), and spherical-shaped (30.5°C) food materials achieved maximum temperatures of 83.9°C, 110.6°C, and 146.1°C respectively. The temperature variations and drying characteristics of the food samples have been monitored. An oven has achieved maximum drying efficiency of 25.65% with a slab-shaped sample. For the detection of the cracks and chemical compositions in the food samples, SEM with EDS analysis has been performed. Economic analysis of microwave oven has also been done and payback period has been found as 3.27years.

Review on effect of postharvest illumination by fluorescent and ultraviolet light waves on the quality of vegetables

AbstractPostharvest illumination is an emerging nonthermal preservation technique used to preserve the quality of vegetables. This review aimed to provide an insight into the effect, importance, and limitations of postharvest illumination by fluorescent and ultraviolet (UV) light on the physical and nutraceutical properties of vegetables. It presents the current information on the postharvest application of these two lightings based on the vegetable species. According to the existing studies, both photoperiod and continuous (low‐intensity) fluorescent lighting treatments were beneficial more toward preserving the quality (delaying senescence and deterioration) of postharvest vegetables, mainly leafy vegetables. However, inconsistent results are also possible with the light quality (intensity and duration) on the postharvest fluorescent lighting treatment. According to gathered information, both UV‐B and UV‐C postharvest irradiation has been beneficial in delaying senescence and chlorophyll degradation and inducing bioactive compounds accumulation in some vegetable species. UV‐C application is appeared to have a relatively steady effect on the postharvest storage of vegetables. But UV‐B irradiation effect on the postharvest quality of vegetables was appeared to be dose dependent and not stable. In conclusion, it is important to consider vegetable (species, cultivar, harvesting age, and intact or fresh‐cut), previous treatments/conditions, optimum postharvest lighting condition (illumination source, dose, intensity, and duration), and the storage condition (temperature and relative humidity) for a successful implementation of postharvest illumination. More research is required to explore the postharvest application of fluorescent and UV (UV‐A, UV‐B, UV‐C) irradiation on vegetables.Practical ApplicationsMultiple research approaches have been taken to preserve the postharvest quality of vegetables while minimizing chemical preservation techniques. Postharvest illumination is a nonchemical preservation technique that has attained more interest due to the advantages it holds, such as being highly efficient and residue‐free. Fluorescent and UV lighting on harvested leafy and non‐leafy vegetables are beneficial in delaying senescence and chlorophyll degradation, preserving nutritional quality, and extending the shelf life. With the accessibility of more research data and innovative strategies, the future of postharvest illumination of fluorescent and UV maybe steer toward implementation on commercial scale vegetable production (e.g., during storage and/or transportation).

Impact of lactic acid bacteria on the control of Listeria monocytogenes in ready-to-eat foods

Abstract Due to the increased demand for ready-to-eat (RTE) minimally processed foods, alternatives to chemical and thermal preservation methods to maintain food safety are highly demanded. A significant safety hazard in RTE food products is the growth of the foodborne pathogen Listeria monocytogenes (L. monocytogenes). After processing, recontamination or cross-contamination of L. monocytogenes in RTE food products may occur and the lack of cooking can lead to an increased risk of listeriosis. Further, some RTE food products (e.g. cheese and cured meat) can have a long processing period and shelf life, thus allowing for the growth and proliferation of L. monocytogenes in the food matrix. Lactic acid bacteria (LAB) are generally recognized as safe probiotics and have been proposed as a biological control approach to eliminate foodborne pathogens including L. monocytogenes. LAB have been reported to extend the shelf life of food products and inhibit pathogen proliferation via growth competition and metabolite production. LAB are native microflora of many RTE foods, but only certain LAB may inhibit pathogen growth. Therefore, the specificity of LAB species should be employed in their use in RTE foods. This review will discuss the antimicrobial mechanisms of LAB against L. monocytogenes, selective use of LAB in food matrices, and their uses in food processing and packaging.

Time-Integrative Multibiomarker Detection in Triassic–Jurassic Rocks from the Atacama Desert: Relevance to the Search for Basic Life Beyond Earth

Detecting evidence of life on other planetary bodies requires a certain understanding of known biomarkers and their chemical nature, preservation potential, or biological specificity. In a planetary search for life, carbonates are of special interest due to their known association with life as we know it. On Earth, carbonates serve as an invaluable paleogeochemical archive of fossils of up to billions of years old. Here, we investigated biomarker profiles on three Chilean Triassic-Jurassic sedimentary records regarding our search for signs of past and present life over ∼200 Ma. A multianalytical platform that combines lipid-derived biomarkers, metaproteomics, and a life detector chip (LDChip) is considered in the detection of biomolecules with different perdurability and source-diagnosis potential. The combined identification of proteins with positive LDChip inmunodetections provides metabolic information and taxonomic affiliation of modern/subrecent biosignatures. Molecular and isotopic analysis of more perdurable hydrocarbon cores allows for the identification of general biosources and dominant autotrophic pathways over time, as well as recreation of prevailing redox conditions over ∼200 Ma. We demonstrate how extraterrestrial life detection can benefit from the use of different biomarkers to overcome diagnosis limitations due to a lack of specificity and/or alteration over time. Our findings have implications for future astrobiological missions to Mars.

Hyper-Cross-Linked Polystyrene as a Stabilizing Medium for Small Metal Clusters

Among different polymers nanostructured cross-linked aromatics have the greatest potential as catalytic supports due to their exceptional thermal and chemical stability and preservation of the active phase morphology. This work studies the ability of hyper-cross-linked polystyrene (HPS) to stabilize small Pdn and Ptn (n = 4 or 9) clusters. Unrestricted DFT calculations were carried out for benzene (BZ) adsorption at the BP level of theory using triple-zeta basis sets. The adsorption of BZ rings (stepwise from one to four) was found to result in noticeable gain in energy and stabilization of resulting adsorption complexes. Moreover, the interaction of metal clusters with HPS micropores was also addressed. For the first time, the incorporation of small clusters in the HPS structure was shown to influences its geometry resulting in the stabilization of polymer due to its partial relaxation.

A review of coral bleaching specimen collection, preservation, and laboratory processing methods.

Under current climate warming predictions, the future of coral reefs is dire. With projected coral reef decline, it is likely that coral specimens for bleaching research will increasingly become a more limited resource in the future. By adopting a holistic approach through increased collaborations, coral bleaching scientists can maximize a specimen’s investigative yield, thus reducing the need to remove more coral material from the reef. Yet to expand a specimen’s utility for additional analytic methods, information on how corals are collected is essential as many methods are variably sensitive to upstream handling and processing. In an effort to identify common practices for coral collection, sacrifice, preservation, and processing in coral bleaching research, we surveyed the literature from the last 6.5 years and created and analyzed the resulting dataset of 171 publications. Since January 2014, at least 21,890 coral specimens were collected for bleaching surveys or bleaching experiments. These specimens spanned 122 species of scleractinian corals where the most frequently sampled were Acropora millepora, Pocillopora damicornis, and Stylophora pistillata. Almost 90% of studies removed fragments from the reef, 6% collected skeletal cores, and 3% collected mucus specimens. The most common methods for sacrificing specimens were snap freezing with liquid nitrogen, chemical preservation (e.g., with ethanol or nucleic acid stabilizing buffer), or airbrushing live fragments. We also characterized 37 distinct methodological pathways from collection to processing of specimens in preparation for a variety of physiological, -omic, microscopy, and imaging analyses. Interestingly, almost half of all studies used only one of six different pathways. These similarities in collection, preservation, and processing methods illustrate that archived coral specimens could be readily shared among researchers for additional analyses. In addition, our review provides a reference for future researchers who are considering which methodological pathway to select to maximize the utility of coral bleaching specimens that they collect.

Comparative chemical investigations of alum treated archaeological wood from various museum collections

From the mid-1800s to the late 1960s, conservation by alum salts (KAl(SO4)2·12H2O—potassium aluminium sulphate), using various recipes, was a common method to prevent shrinkage and to strengthen waterlogged archaeological wooden objects. This method was mainly used in Scandinavia. The alum method appears to have also been applied to highly degraded archaeological waterlogged wood in other countries, for example in the U.S and Germany. Today, many of the archaeological wooden objects treated with alum show extreme deterioration and very low pH, which are attributed to the effects of the alum-treatment. This study investigated the extent of the current levels of chemical degradation in wooden objects conserved with alum salts at different points in time (1880s, 1930s and 1905–13) in order to understand their current condition and whether extent of degradation was in any way related to time of treatment, in an attempt to understand the rate of degradation. It was also an opportunity to compare the chemical state of preservation of alum-treated wood from different collections, as only the Oseberg collection has been intensively studied in this way up until now. Samples from historical wooden objects from the following collections were investigated and compared: the Dejbjerg collection (National Museum of Denmark in Copenhagen); the Oseberg collection (Museum of Cultural History, Oslo, Norway); the Glimmingehus collection (Swedish History Museum, Sweden). Analyses of lignocellulosic polymers and of inorganic compounds were undertaken to evaluate the chemical preservation of the wooden objects. The investigations were performed using a multi-analytical approach which consisted of: pH measurements, analytical pyrolysis (Py-GC/MS), X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS). It was possible to link the extent of degradation with time, on a general level but we found a great variability in the state of preservation of the wood also within the same collection. It is clear, however that alum-treated wood is more degraded than archaeological wood not treated with alum.

Late Stage Decomposition of Embalmed Cadavers

Decomposition is a natural process that begins approximately four minutes after death and continues until the body is degraded to simpler biochemical components which are gradually recycled back to the environment. This process is dependent on extrinsic and intrinsic factors. Embalming is a chemical preservation technique that aims to preserve the external appearance of the body in good condition for an indeterminate period. In Spain, there is a lack of experimental studies carried out to analyse the variables that affect decomposition in embalmed bodies, therefore, in accordance with the conclusions reached by previous authors, it is hypothesised that embalmed bodies show quantifiable characteristics during the late stage decomposition which distinguish them from control, unembalmed, cadavers. An anthropological and statistical analysis was performed on 14 individuals from Cementerio Sur de Madrid exhumed after ten years according to the Mortuary Health Law of the Autonomous Region of Madrid. The preliminary results obtained showed that there is a qualitative and statistically significant relationship between the variables evaluated, being the presence or absence of soft tissue the most notable difference. The mortuary or thanatopraxy treatments performed before the burial and the microenvironmental conditions of the burial positively influence the soft tissue preservation on embalmed bodies. These results contribute to the understanding about the decomposition rate of an embalmed cadavers in cemeteries, and the related extrinsic variables.

γ-Irradiated Chitosan From Carcinoscorpius rotundicauda (Latreille, 1802) Improves the Shelf Life of Refrigerated Aquatic Products

The γ-irradiated horseshoe crab chitosan was used as food coating to extend the shelf life of marine shrimp and fish. Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), and X-ray diffraction (XRD) were used to characterize the γ-irradiated chitosan. After employing control (untreated seafood samples/no preservatives), chemical preservation (treated with 2% glacial acetic acid) and 2% chitosan (0, 10, and 20 kGy γ-irradiation) for the assessment assay, the shrimp (Penaeus merguiensis), pomfret (Pampus argenteus), and hilsa fish (Tenualosa ilisha) samples were examined for pH, thiobarbituric acid reactive substance (TBARS), total viable counts (TVC), and sensory evaluation changes while under 15-day refrigeration at 4°C. The results of FT-IR, XRD, and FE-SEM analysis revealed that irradiated chitosan possessed a crystalline structure with smooth texture on its surface. Analysis of pH, TBARS, TVC, and sensory evaluation demarcated irradiated chitosan with the ability to delay microbial growth and this prolonged the shelf life of refrigerated shrimp and fish. With novelty on γ-irradiated horseshoe crab chitosan use as natural preserving agent, fisheries industries and food packaging practitioners would benefit from its microbial-inert abilities particularly for long distant cold storage transport of packaged marine meats.

Chemical preservation for increasing shelf life of Chrysanthemum indicum L. cut flower

Chrysanthemum indicum L. is the second most important ornamental and marketable flower from Asteraceae family in the world. Vase life is a main factor for evaluating the post-harvest quality of cut flowers that determine their marketability. Chrysanthemum is one of the top most cut flowers sold in international flower markets. The post-harvest study was carried out on chrysanthemum cut flower to observe the effect of different chemical preservatives solution for vase life. Here, the different chemical preservative treatments consisting of sucrose, salicylic acid, citric acid, aluminum sulphate and their combination were used to increase the vase life and the petal discoloration of chrysanthemum cut flowers. It was observed that all the preservatives treatments (expect T3) extend the vase life and reduced petal discoloration over the control. The result showed in containing T2 [sugar (4%) + salicylic acid (100ppm)] and T6 [citric acid (150ppm) + aluminum sulphate (500ppm) +7% sucrose] resulted in maximum vase life 18 days and 16 days in room temperature and reduced leaf browning more than control. Cite as Dhrumi Patel, Rachana Suthar, & Hiteshkumar A. Solanki. (2021). Chemical preservation for increasing shelf life of Chrysanthemum indicum L. cut flower. Research and Reviews: Journal of Environmental Sciences, 3(1), 1–7. http://doi.org/10.5281/zenodo.4668605

A Preliminary Study of Chemically Preserved and High-Moisture Whole Maize (Zea mays L.) Usage in Pekin Duck Nutrition: Effect on Growth Performance and Selected Internal Organ Traits.

Simple SummaryHarvested maize grains characterized by high moisture require the use of additional preservation processes to secure against the microbiota. The most commonly used practice is heat-drying, which is energy- and cost-consuming, as well as environmentally unfriendly. Thus, there is a need to omit these harmful techniques and evaluate the usage of wet maize in animal nutrition. The present study aimed to investigate the effect of the chemically preserved, high-moisture whole maize grain addition in Pekin duck nutrition on their growth performance and selected internal organ and gastrointestinal tract measurements and digesta pH values. The results of the experiment clearly showed that there is a possibility to partially replace commonly used heat-dry maize with the preserved whole-grain form without an adverse effect on the birds’ performances and selected organ morphometrical parameters. However, due to surprising changes in the pH values in the gizzard and caeca, further investigations, including microbiota analyses, are recommended.This study aimed to investigate the effect of chemically preserved, high-moisture whole maize grain addition in Pekin duck diets on their growth performance and selected internal organ and gastrointestinal tract measurements and digesta pH values. A total of 300 29-d-old male Pekin ducks were randomly distributed into three dietary treatments using five replicate pens per group and 20 birds per pen. The following treatment groups were applied: CON—basal diet, 5HM—5% of high-moisture, chemically preserved whole maize (HM) inclusion, and 10HM—10% of HM addition. The experiment lasted 21 d. The implementation of 5HM or 10HM did not affect (p > 0.05) the growth performance parameters, selected internal organ weights, and the gastrointestinal tract segment weights and lengths. However, significant changes in terms of the gizzard (p = 0.005), ileum (p = 0.030), and caecal (p < 0.001) digesta pH were observed, especially in the case of the 10HM group, which exhibited the greatest increase in pH in the gizzard and caecal digesta and decrease in the ileal digesta pH. The implementation of whole wet maize may be used in waterfowl diets from 29 d of age. Additionally, chemical preservation can efficiently reduce the cost of maize preparation in duck nutrition.

Effective low-cost preservation of human stools in field-based studies for helminth and microbiota analysis

Molecular studies of gastrointestinal infections or microbiotas require either rapid sample processing or effective interim preservation. This is difficult in remote settings in low-income countries, where the majority of the global infectious disease burden exists. Processing or freezing of samples immediately upon collection is often not feasible and the cost of commercial preservatives is prohibitive. We compared fresh freezing (the ‘gold standard’ method), with low-cost chemical preservation in (i) a salt-based buffer consisting of DMSO, EDTA and NaCl (DESS) or (ii) 2.5% potassium dichromate (PD), for soil-transmitted helminth detection and microbiota characterisation in pre-school and school-aged children from north-western Thailand. Fresh frozen samples were frozen at −20°C on collection and maintained at −80°C within ~3 days of collection until molecular analysis, with international shipping on dry ice. In contrast, chemically preserved samples were collected and stored at ~4°C, transported on wet ice and only stored at −20°C on arrival in Australia ~8 weeks after collection, with international shipping on wet ice. DESS and PD provided better sensitivity for STH diagnosis, estimating higher infection rates (>80% for Ascaris lumbricoides and >60% for Trichuris trichiura; versus 56% and 15% for these parasites in fresh frozen samples) and egg abundance (inferred as gene copy number estimates). All methods performed similarly for microbiota preservation, showing no significant differences in alpha-diversity based on overall richness or inverted Simpson’s Index. All three methods performed similarly for RNA and protein preservation in a small subset of samples. Overall, DESS provided the best performance, with the added benefit of being non-toxic, compared with PD, hence making it particularly applicable for studies in remote and resource-poor settings.