Microplastic Release from Single-Use Plastic Beverage Cups.

Microplastics (MPs) have attracted considerable attention as one of the most remarkable food and drink pollutants in recent years. Disposable cups, which are widely used as single-use containers, have been suspected as the primary sources of MPs found in cold and hot beverages. In this study, the effect of different exposure times (0, 5, 10 and 20 min) and temperatures (4 °C, 50 °C and 80 °C) on MP release from the single-use cups made of four different materials [polypropylene (PP), polystyrene (PS), polyethylene (PE) coated paper cups and expanded polystyrene (EPS)] into the water was investigated. The number of MPs ranged from 126 p/L to 1420 p/L, while the highest and lowest counts were observed in the PP (50 °C for 20 min) and PE-coated paper cups (4 °C 0 min), respectively. Washing the cups with ultrapure water prior to use reduced the MP release by 52-65%. SEM images demonstrated the abrasion on the surface of the disposable cups as a result of hot water exposure. Intensities of FTIR absorbance levels at some wavelengths were decreased by the water treatment, which could be evidence of surface abrasion. The annual MP exposure of consumers was calculated as 18,720-73,840 by the consumption of hot and cold beverages in disposable cups. In conclusion, as the level and potential toxicity of MP exposure in humans are not yet fully known, this study sheds light on the number of MPs transferred to cold and hot beverages from single-use disposable cups.

Effects of Autochthonous Yeast Cultures on Some Quality Characteristics of Traditional Turkish Fermented Sausage "Sucuk".

The objective of this study was to determine the effects of yeast cultures (Candida zeylanoides and Debaryomyces hansenii) isolated from traditionally dry fermented Turkish sucuks, on some physicochemical and microbiological properties of the product. Eight different batches of the sucuks were produced by the inoculation of yeast and lactic acid bacteria (LAB) cultures (Lactobacillus curvatus, Lactobacillus plantarum and Lactobacillus sakei) in different combinations. The sucuks were ripened for 12 days and analyzed at 1st, 6th, and 12th days of ripening. Percent moisture content, pH, water activity (aw) and residual nitrite values of the sucuk inoculated with the yeast cultures were higher at the end of the ripening. The use of yeast cultures decreased hardness, gumminess, and chewiness values of the sucuk while increased adhesiveness values. Major volatile groups were aldehydes, terpenes, and sulphur compounds in the sucuk samples. The most noticeable results were for sensory properties of the sucuk that were positively improved by the yeast cultures.

Using a hybrid technology to produce traditional sourdough Gelveri bread: infrared cooking assisted with traditional method.

Traditional foods are known as special products that do not have a specific production technology and are transferred traditionally from generation to generation. The most important feature that distinguishes Gelveri bread from the other bread is the use of sourdough technique and cooking in stone kilns. It is one of the traditional foods produced in Turkey for hundreds of years. We believe that standardization and commercialization of Gelveri bread will be challenging initiative to contribute to the local and national economy. Therefore, this study aimed to investigate the possibility of using infrared (IR) and ultraviolet-C technologies in the commercialization of traditional Gelveri bread production that abides by the sourdough technique. Traditionally Gelveri bread dough was prepared and cooked with the infrared oven designed for this study. Following the cooking step, some physicochemical and microbiological quality characteristics and shelf life of the Gelveri bread were investigated. The results indicated that the microbiological quality and shelf life were improved with the IR application without effecting the other quality parameters. On the other hand, a small decrease in pH was observed. As a result, it was concluded that if IR furnace integrated into the stone kilns, the quality of the bread might be standardized, and the sustainability of the traditional method will be ensured.

Developmental Concerns, Parental Perceptions and Missed Opportunities from Different Levels of Health Centers in a Middle-Income Country.

OBJECTIVE: To evaluate the concerns the parents have with the development of their children and related conditions and investigate how often these concerns are addressed at all levels of the healthcare system. Determining parental perceptions of these issues and highlighting missed opportunities is valuable for improving healthcare services. METHODS: A total of 451 parents attending a medical appointment for their children in outpatient clinics at tertiary, secondary and primary health centers were administered a questionnaire comprised of 45 questions pertaining to their concerns regarding the development of their children and related conditions, including sociodemographic characteristics, practices supporting child development, information resources and personal opinions, such as whether they had sufficient information. RESULTS: The parents of 130 children (28.8%) reported at least one developmental concern. Less than half of the concerned parents had visited a health center for these concerns. The area of greatest concern was language development, but the concerns differed based on setting. Among the related factors, having insufficient information (p = 0.000, OR: 0.375, CI: 0.24-0.58) and not playing with the child (p = 0.029, OR: 0.563, CI: 0.33-0.94) increased the risk of having developmental concerns. Only 15.5% of children were followed up in a developmental and behavioral manner. CONCLUSIONS: The authors observed many concerns and missed opportunities to address them at all levels of health centers. Family physicians were more effective at eliciting these issues than pediatricians. These issues need to be addressed in the health system with consideration of its complexity and integrated culture.

Effects of different flour blends with varying protein content and quality on dough and crust properties of "etliekmek", a pizza-like traditional food of Turkey.

Etliekmek, which somewhat resembles pizza in terms of crust and toppings, is a widely consumed traditional food in Turkey. It consists of a sheeted dough topped with a mixture of minced meat and some vegetables. In this study, the effects on dough processing and crust properties of etliekmek of five flour blends with varying protein content and quality were investigated. The blends (Blend-1 through Blend-5) consisted respectively of hard-endosperm Bezostaja and soft-endosperm Gerek-79 wheat flours at the ratios of 100:0, 75:25, 50:50, 25:75 and 0:100. In addition to pysicochemical properties of wheats and their flour blends, dough processing and etliekmek crust properties were measured through the instrumental and sensory approaches. It was determined that protein contents and qualities of the blends decreased from Blend-1 through Blend-5. The dough from Blend-1 was judged to be extremely elastic, which resisted to sheeting due to elastic recovery, whereas the dough from Blend-5 was scored to be somewhat weak and easily extensible. The most suitable dough for the processing of etliekmek crust, i.e., optimally elastic and properly extensible dough with appropriate sheetability, seemed to be 50:50 blend of Bezostaja and Gerek-79 flours (Blend-3). Blend-1 yielded etliekmek crust with thick, moist and excessively chewy texture, as opposed to the thinner, drier and rather crunchy crust texture from Blend-5. Based on the dimensional measurements and sensory evaluations, Blend-3 yielded the best etliekmek crust. The results demonstrate that an optimum balance of dough viscosity and elasticity, which are mostly governed by flour protein content and quality, is of vital importance to the production of high-quality etliekmek crust.

Development of LLDPE based active nanocomposite films with nanoclays impregnated with volatile compounds.

In this study, a novel procedure was performed for grafting of nanoclays (montmorillonite (MMT) and halloysite (HNT)) with essential oil constituents (thymol (THY), eugenol (EUG) and carvacrol (CRV)) using Tween 80 as surfactant and then the nanoclay particles were incorporated into LLDPE pellets (5 wt%) to produce active nanocomposite films using a twin screw extruder. The resulting nanocomposite films were analyzed for antimicrobial and antioxidant capacity as well as thickness, mechanical, color, barrier, thermal properties and surface morphology and molecular composition. Release of the active compounds from the films at the refrigerated and room temperature conditions were also tested. The results showed that the films had strong in vitro antibacterial activity against pathogenic bacteria (Salmonella Typhimurium, Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus) while their effect against lactic acid bacteria (Lactobacillus rhamnosus and Lb. casei) was limited. The lowest and highest DPPH scavenging ability levels were 65.59% and % 87.92, belonged to THY-MMT and EUG-MMT, respectively. Release of active compounds at 24 °C was much more rapid than at 4 °C. CRV-HNT and THY-HNT provided slower release than the other films. SEM results showed that nanoclays were uniformly dispersed in the polymer matrix with exceptional agglomerates. Incorporation of the active nanoclays significantly (P > 0.05) improved tensile strength and elongation of the films. The results confirmed that LLDPE based active nanocomposite films could be successfully produced due to its good interaction with MMT and HNT, activated with THY, EUG and CRV.

Targeting the pains of food insecurity and malnutrition among internally displaced persons with nutrient synergy and analgesics in organ meat.

Living with pain is one of the distressing effects of food insecurity and malnutrition among millions of internally displaced persons (IDPs) worldwide. Vulnerability to emotional pain, metabolic imbalance, chronic illnesses and non-communicable diseases by IDPs are associated with stressed livelihood and restricted access to balanced diets in their camps. Tackling the complexity of issues related to internal displacement is challenging as 45% are globally trapped in protracted conditions. In this review, a diet-based intervention is proposed considering the potential benefits of nutrient synergy and analgesic constituents in organ meat. Providing an affordable, value added and well packaged nutrient dense diet is suggested to meet daily protein and micronutrient requirements from organ meat. Also, unlocking health-promoting bioactive substances and analgesics in restructured organ meat product is proposed as personalized dietary remedy to exert opioid bioactivity in food matrix. Exploiting the nutrient synergy of this animal by-product will not only improve the nutritional status or wellbeing but also raise the composite score of dietary diversity or food security index among IDPs by 2030.

Assessment of Multi Fragment Melting Analysis System (MFMAS) for the Identification of Food-Borne Yeasts.

Multi Fragment Melting Analysis System (MFMAS) is a novel approach that was developed for the species-level identification of microorganisms. It is a software-assisted system that performs concurrent melting analysis of 8 different DNA fragments to obtain a fingerprint of each strain analyzed. The identification is performed according to the comparison of these fingerprints with the fingerprints of known yeast species recorded in a database to obtain the best possible match. In this study, applicability of the yeast version of the MFMAS (MFMAS-yeast) was evaluated for the identification of food-associated yeast species. For this purpose, in this study, a total of 145 yeast strains originated from foods and beverages and 19 standard yeast strains were tested. The DNAs isolated from these yeast strains were analyzed by the MFMAS, and their species were successfully identified with a similarity rate of 95% or higher. It was shown that the strains belonged to 43 different yeast species that are widely found in the foods. A clear discrimination was also observed in the phylogenetically related species. In conclusion, it might be suggested that the MFMAS-yeast seems to be a highly promising approach for a rapid, accurate, and one-step identification of the yeasts isolated from food products and/or their processing environments.

Erratum to: Application of high-resolution melting analysis for differentiation of spoilage yeasts.

In the article by Erdem et al. published in Journal of Microbiology 2016; 54, 618-625, the figure 1 should be corrected as below.

Utilization of fermented soybeans paste as flavoring lamination for Turkish dry-cured meat.

The effects of utilizing fermented soybeans paste (miso) as an alternative flavor-coating material for eliminating unpleasant odor of sulphuric and sotolone compounds from cemen in commercial pastirma were investigated. Results showed that miso-pastirma (MP) and commercial pastirma (CP) had higher L* values in comparison with the fresh meat. While no pathogen was detected in all the meat samples, statistically significant stearic acid was increased (P<0.05) and also oleic and arachidic acids were observed in MP. SDS-PAGE patterns indicated that miso had higher impacts on muscle proteins than cemen suggesting that miso can generate proteins and peptides with better technological or nutritional properties. None of the sulphur containing compounds responsible for unpleasant odor was detected in MP. Limonene, 5 esters, beta-pinene and saponins in MP contributed to citrus fruit aroma with smoother, roasty flavor and delicious taste. These findings suggest that miso contain good flavoring molecules for enhancing fruity smell and quality of pastirma. Thus, laminating cured meat with miso can be used as an alternative to cemen for producing healthier pastirma with extended shelf life and better flavor.

Application of high-resolution melting analysis for differentiation of spoilage yeasts.

A new method based on high resolution melting (HRM) analysis was developed for the differentiation and classification of the yeast species that cause food spoilage. A total 134 strains belonging to 21 different yeast species were examined to evaluate the discriminative power of HRM analysis. Two different highly variable DNA regions on the 26 rRNA gene were targeted to produce the HRM profiles of each strain. HRM-based grouping was compared and confirmed by (GTG)5 rep-PCR fingerprinting analysis. All of the yeast species belonging to the genera Pichia, Candida, Kazachstania, Kluyveromyces, Debaryomyces, Dekkera, Saccharomyces, Torulaspora, Ustilago, and Yarrowia, which were produced as species-specific HRM profiles, allowed discrimination at species and/or strain level. The HRM analysis of both target regions provided successful discrimination that correlated with rep-PCR fingerprinting analysis. Consequently, the HRM analysis has the potential for use in the rapid and accurate classification and typing of yeast species isolated from different foods to determine their sources and routes as well as to prevent contamination.

Steady shear rheological characteristics of model system meat emulsions: Power law and exponential type models to describe effect of corn oil concentration.

The effect of oil concentration (57.50, 58.75, 60.00 and 61.25 %) and temperature (5, 10 and 15 ºC) on steady shear rheological properties of O/W model system meat emulsions were investigated. The effect of temperature and oil concentration was modeled using power law and exponential type functions. The meat emulsions showed non-Newtonian flow behavior because flow behavior index was lower than unity. Consistency coefficient and flow behavior index values of O/W model system meat emulsions were calculated using Oswald de Waele model with higher coefficients of determination. Apparent viscosities of emulsions at a specified shear rate (50 s(-1)) were in the range of 0.652-0.941 Pa s. Increasing oil concentration provided an increase in apparent viscosity and increase in temperature levels resulted a decrease in consistency coefficient values. The exponential function performed better than the power-law function (R (2) > 0.922) in terms of describing the effect of oil concentration on the steady shear rheological properties of the model system meat emulsions. Higher coefficients of determination (R (2) = 0.979-0.999) were observed in exponential-type function compared to a power law function (R (2) = 0.880-0.946).

Effect of yoghurt or yoghurt serum on microbial quality of cig kofte.

Cig kofte, raw meatball is a traditionally produced meat product in Turkey and some other Middle East countries. It is prepared from mixtures of finely minced raw beef, bulgur, onions, various spices and tap water. Cig kofte is an uncooked product and popularly consumed with lettuce and lemon juice. In this study, yoghurt or yoghurt serum (YS) were added to the mixtures of cig kofte instead of tap water to reduce microbial risks of the raw meatball. Additionally, the effects of yoghurt and YS on some physicochemical characteristics of cig kofte were investigated. Cig kofte is generally consumed within a few hours after the preparation because of its raw nature. Also, it is generally sold under unhygienic conditions in restaurants and restaurant-like places. For this purpose, reducing of the microbial load of cig kofte is important. In the results, Escherichia coli and Listeria monocytogenes were not detected in any samples. While lactic acid bacteria count increased by addition of yoghurt and YS, the number of other microorganisms except for total aerobic mesophilic bacteria (TAMB) were decreased. The aw values and% moisture contents of the samples were varied between 0.88-0.94 and 46.25-49.72, respectively. The pH values of the samples were slightly changed during the storage of 24 h while no changes detected in the control samples during the storage. In conclusion, it can be suggested that using the yoghurt or YS instead of tap water in the preparation of cig kofte might ensure the microbial safety, increase the nutritional value and its flavour or aroma.

Application of different molecular techniques for characterization of catalase-positive cocci isolated from sucuk.

This study was carried out for the characterization and discrimination of the indigenous Gram positive, catalase-positive cocci (GCC) population in sucuk, a traditional Turkish dry-fermented sausage. Sucuk samples, produced by the traditional method without starter culture were collected from 8 local producers in Kayseri/Turkey and a total of 116 GCC isolates were identified by using different molecular techniques. Two different molecular fingerprinting methods; namely, randomly amplified polymorphic DNA-PCR (RAPD-PCR) and repetitive extragenic palindrome-PCR (rep-PCR), were used for the clustering of isolates and identification at species level was carried out by full length sequencing of 16S rDNA. Combining the results obtained from molecular fingerprinting and 16S rDNA sequencing showed that the dominant GCC species isolated from the sucuk samples was Staphylococcus saprophyticus followed by Staphylococcus succinus and Staphylococcus equorum belonging to the Staphylococcus genus. Real-time PCR DNA melting curve analysis and high-resolution melting (HRM) analysis targeting the V1 + V3 regions of 16S rDNA were also applied for the discrimination of isolates belonging to different species. It was observed statistically different Tm values and species-specific HRM profiles for all except 2 species (S. saprophyticus and Staphylococcus xylosus) that have high 16S rDNA sequence similarity. The combination of rep-PCR and/or PCR-RAPD with 16S rRNA gene sequencing was an efficient approach for the characterization and identification of the GCC population in spontaneously fermented sucuk. On the other hand, intercalating dye assays were found to be a simple and very promising technique for the differentiation of the GCC population at species level.

Diversity and probiotic potentials of lactic acid bacteria isolated from gilaburu, a traditional Turkish fermented European cranberrybush (Viburnum opulus L.) fruit drink.

The aim of the present study was to characterize lactic acid bacteria (LAB) strains isolated from traditional fermented gilaburu fruit juice and their probiotic potential. The LAB counts of the fermented gilaburu fruit juice were in the range of 3.92-8.30logcfu/g. Total of 332 isolates belonging to Lactobacillus and Leuconostoc species were characterized from traditional fermented gilaburu juice by genotypic methods. It was also determined that the major LAB strains belong to Lactobacillus plantarum (173 isolates), Lactobacillus casei (52 isolates) and Lactobacillus brevis (24 isolates), while Lactobacillus buchneri, Lactobacillus parabuchneri, Lactobacillus pantheris, Leuconostoc pseudomesenteroides and Lactobacillus harbinensis were the least in isolated LAB strains. In terms of the probiotic potentials, Lb. plantarum strains were able to grow at pH2.5, but 3 of Lb. casei strains, one of each Lb. brevis and Lb. buchneri strains could not grow at the same pH. All selected LAB stains were resistant to bile salt at ≤0.3% concentration. While all the LAB species grew at 15°C, two Lactobacillus hordei strains could also grow at 45°C. The highest cell hydrophobicity degrees were for Lb. casei (G20a) and Lb. plantarum (G19e) as 87.5 and 86.0%, respectively. Listeria monocytogenes and Bacillus cereus were the most sensitive bacteria against the selected LAB strains, while Escherichia coli and Staphylococcus aureus were the most resistant. Again all the isolated LAB species were resistant to three antibiotics; kanamycin, streptomycin and vancomycin. Characterization and probiotic potentials of the LAB isolated from fermented gilaburu (Viburnum opulus) juice were studied first time, and further research needs to be done on their behaviors in similar food formulations as a probiotic.

A novel method to differentiate bovine and porcine gelatins in food products: nanoUPLC-ESI-Q-TOF-MS(E) based data independent acquisition technique to detect marker peptides in gelatin.

We presented a novel nanoUPLC-MS(E) workflow method that has potential to identify origin of gelatin in some dairy products; yoghurt, cheese and ice cream. In this study, the method was performed in two steps. In the first step, gelatin was extracted from these products before the MS-sample preparation. In the second step, tryptic gelatin peptides were separated and analyzed with ultra-performance liquid chromatography and electrospray ionization quadrupole time-of-flight mass spectrometry (nanoUPLC-ESI-q-TOF-MS(E)). The novelty of this setup was that it functioned in a data independent acquisition mode and that alternate low and elevated collision energy was applied to acquire precursor and product ion information. This enabled accurate mass acquisition on the peptide level to identify the gelatin peptides. The marker peptides specific for porcine and bovine could be successfully detected in the gelatin added to the dairy products analyzed, revealing that the detection of marker peptides in the digested gelatin samples using nanoUPLC-ESI-q-TOF-MS(E) could be an effective method to differentiate porcine and bovine gelatin in the dairy products.

Detection of chicken and turkey meat in meat mixtures by using real-time PCR assays.

In this study, TaqMan-based real-time Polymerase Chain Reaction (PCR) techniques were developed for the detection of chicken and turkey meat in raw and heat-treated meat mixtures. Primers and TaqMan probe sets were designed to amplify 86 bp and 136 bp fragments for the chicken and turkey species, respectively, on the mitochondrial NADH dehydrogenase subunit 2 gene. In the results, it was possible to detect each species at the level of 0.1 pg template DNA with the TaqMan probe technique without any cross-reactivity with nontarget species (bovine, ovine, donkey, pork, and horse) while the detection level was 1 pg template DNA using conventional PCR. The TaqMan probe assays used in this study allowed the detection of as little as 0.001% level of both species in the experimental meat mixtures, prepared by mixing chicken and turkey meat with beef at different levels (0.001% to 10%). In conclusion, TaqMan probe assays developed in this research are promising tools in the specific identification and sensitive quantification of meat species even in the case of heat-treated meat products, and suitable for a rapid, automated, and routine analysis.

Efficacy of various plant hydrosols as natural food sanitizers in reducing Escherichia coli O157:H7 and Salmonella Typhimurium on fresh cut carrots and apples.

In the present study, inhibitory effects of the hydrosols of thyme, black cumin, sage, rosemary and bay leaf were investigated against Salmonella Typhimurium and Escherichia coli O157:H7 inoculated to apple and carrots (at the ratio of 5.81 and 5.81 log cfu/g for S. Typhimurium, and 5.90 and 5.70 log cfu/g for E. coli O157:H7 on to apple and carrot, respectively). After the inoculation of S. Typhimurium or E. coli O157:H7, shredded apple and carrot samples were washed with the hydrosols and sterile tap water (as control) for 0, 20, 40 and 60 min. While the sterile tap water was ineffective in reducing (P>0.05) S. Typhimurium and E. coli O157:H7, 20 min hydrosol treatment caused a significant (P<0.05) reduction compared to the control group. On the other hand, thyme and rosemary hydrosol treatments for 20 min produced a reduction of 1.42 and 1.33 log cfu/g respectively in the E. coli O157:H7 population on apples. Additional reductions were not always observed with increasing treatment time. Moreover, thyme hydrosol showed the highest antibacterial effect on both S. Typhimurium and E. coli O157:H7 counts. Inhibitory effect of thyme hydrosol on S. Typhimurium was higher than that for E. coli O157:H7. Bay leaf hydrosol treatments for 60 min reduced significantly (P<0.05) E. coli O157:H7 population on apple and carrot samples. In conclusion, it was shown that plant hydrosols, especially thyme hydrosol, could be used as a convenient sanitizing agent during the washing of fresh-cut fruits and vegetables.

RP-HPLC-DAD analysis of phenolic compounds in pomace extracts from five grape cultivars: Evaluation of their antioxidant, antiradical and antifungal activities in orange and apple juices.

Phenolic compounds, related to antioxidative and antifungal properties of ethanolic extracts from five commercial grape cultivars (three red and two white) grown in Turkey were determined. A reversed-phase high performance liquid chromatography (RP-HPLC) procedure was developed, and a total 18 different phenolic compounds were identified. Total phenolic contents of the extracts were determined using Folin-Ciocalteau method. Antioxidant activities of the extracts were evaluated by using DPPH radical scavenging and phosphomolybdenum methods. All extracts exhibited strong antioxidant and antiradical activity. Phenolic compounds and antioxidant activities of the extracts were variety dependent. Antifungal activities of the pomaces and extracts were screened by both in vitro agar-well diffusion assay and antifungal activity in apple and orange juices in situ using Zygosaccharomyces rouxii and Z. bailii. Antifungal activities revealed that the pomaces and extracts of Gamay and Kalecik karasi could be more effective antifungal agents than those of Emir, Narince and Okuzgozu grape cultivars.

Effect of grape pomace extracts obtained from different grape varieties on microbial quality of beef patty.

UNLABELLED: Grape pomace extracts were obtained from 5 different grape varieties grown in Turkey. The extracts were concentrated to obtain crude extracts; and incorporated into beef patties at 0% (Control), 1%, 2%, 5%, and 10% concentrations to test their antimicrobial effects in different storage periods (first, 12, 24, and 48 h). The numbers of microorganism were generally decreased by the extract concentration during the storage period. All the microorganisms tested were inhibited by the extract concentration of 10% in all the storage periods. Furthermore, the foodborne pathogens including Enterobacteriaceae and coliform bacteria, and the spoilage microorganisms including yeasts and moulds and lipolytic bacteria were also inhibited by 5% of Emir, Gamay, and Kalecik Karasi varieties in beef patties. Considering the results, the extracts of grape pomaces might be a good choice in the microbial shelf life extension of the food products as well as inhibiting the food pathogens as the case of beef patties. PRACTICAL APPLICATION: Grape pomace consists of seeds, skins, and stems, and an important by-product that is well known to be the rich source of phenolic compounds, both flavonoids and non-flavonoids. These substances have considerable beneficial effects on human health. The use of natural antimicrobial compounds, like plant extracts of herbs and spices for the preservation of foods has been very popular issue because of their antimicrobial activity. Therefore, grape pomace should be added into some food formulations to benefit from their protective effects. In this respect, this study reports the effect of addition of grape pomace extracts obtained from different grape varieties on microbial quality of beef patty. The results obtained in this study may be useful for food industry, which has recently tended to use natural antimicrobial sources in place of synthetic preservatives to prevent microbial spoilage.