INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)  
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue XI November 2025  
Comparative Evaluation of Microbial Contamination and Nutritional  
Composition of Locally Procured, Prepared and Preserved Tomato Paste  
(Within Bwari and GwagwaladaArea Councils, FCT-Abuja) Using Glass  
Bottles  
Zubair, Zainab Oyiza1, Gyebi Gideon Ampoma1,2 , Anyanwu Gabriel1 and Daikwo Moses Alilu1*  
1Department of Biochemistry, Bingham University, Karu, Nasarawa State-Nigeria  
2Durban University of Technology, Faculty of Applied Sciences, Durban, Department of Biotechnology  
and Food Science, South Africa,  
*Corresponding Author  
DOI: https://dx.doi.org/10.51244/IJRSI.2025.12110098  
Received: 17 November 2025; Accepted: 25 November 2025; Published: 10 December 2025  
ABSTRACT  
This study evaluated the microbial contamination and nutritional composition of locally prepared and preserved  
tomato paste using glass bottles compared with industrial tomato paste. Four samples were prepared: homemade  
tomato paste (HP), homemade paste with preservative (HPP), vendor paste (VP), and industrial paste (IP) serving  
as control. Analyses were conducted at Month 1 and Month 3 for sterile samples, and at Month 3 for the spoilage  
study. The parameters analyzed included moisture, ash, crude protein, crude fiber, ether extract, nitrogen-free  
extract (NFE), pH, titratable acidity, vitamin C, and microbial load. Results showed significant differences (p <  
0.05) in moisture content (ranging from 5.45 ± 0.05% to 6.80 ± 0.07%), crude protein (1.91 ± 0.01% to 2.65 ±  
0.05%), and microbial load (2.1 × 10³ to 8.4 × 10⁵ CFU/g) between homemade and industrial samples. Sterile  
samples showed lower microbial counts compared to the spoilage study, indicating effective preservation  
through sterilization and glass bottle storage. The novelty of this study lies in its direct comparison of glass  
bottle–preserved tomato pastes under sterile and non-sterile (spoilage) conditions, providing practical insights  
into the potential of local preservation methods for improving food safety and reducing postharvest losses in  
Nigeria’s tomato value chain.  
Keywords: Tomato paste, preservation, microbial contamination, proximate composition  
INTRODUCTION  
Tomato (Solanum lycopersicum L.) remains one of the most economically valuable and extensively consumed  
horticultural crops worldwide, serving as both a fundamental food ingredient and a significant source of essential  
nutrients such as vitamins, minerals, and bioactive phytochemicals (Hassan et al., 2023). It is particularly  
abundant in lycopene- a carotenoid pigment recognized for its strong antioxidant potential that contributes to the  
mitigation of oxidative stress and the prevention of chronic illnesses, including cardiovascular diseases and  
specific cancer types. In Nigeria, tomatoes play a vital role in improving household nutrition and supporting  
agricultural livelihoods, forming the foundation of numerous indigenous cuisines and processed products, such  
as tomato paste and purée (Eze et al., 2023).  
Despite their high nutritional and economic relevance, tomato production and utilization in Nigeria are  
constrained by severe post-harvest losses, microbial contamination, and inadequate preservation methods  
(Olaniyi & Ojetayo, 2022). Research indicates that approximately 40–50% of harvested tomatoes in tropical  
regions like Nigeria spoil before reaching consumers due to poor handling practices, microbial deterioration, and  
limited processing infrastructure (Nwakuba et al., 2024). Consequently, the production of tomato paste—both  
on local and industrial scales—has become a crucial strategy to minimize post-harvest losses, guarantee year-  
round supply, and extend product shelf-life (Musa et al., 2023).  
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Locally prepared tomato paste can be preserved in glass bottles using either traditional or semi-modern  
approaches, which often differ from industrial processes in terms of microbial safety, nutrient preservation, and  
sensory quality (Ahmed et al., 2022). Glass bottle preservation is environmentally friendly and chemically inert,  
reducing the risk of metallic ion migration commonly observed in tin or aluminum containers (Okoro & Aluko,  
2023). Nevertheless, contamination by microorganisms during preparation or storage can deteriorate product  
quality, particularly when hygienic conditions and sterilization procedures are poorly maintained (Afolabi et al.,  
2022).  
The increasing consumer preference for locally produced tomato paste in Nigeria highlights the importance of  
conducting comparative assessments with industrial tomato paste to determine their relative safety, nutritional  
integrity, and storage stability. Such comparative studies provide valuable evidence for enhancing local  
production practices and establishing preservation standards consistent with national and global food safety  
frameworks, including those of the World Health Organization (WHO), Standards Organization of Nigeria  
(SON), and the National Agency for Food and Drug Administration and Control (NAFDAC) (WHO, 2023).  
The novelty of this research lies in its integrated assessment of microbial contamination and nutritional  
composition of locally prepared, glass-bottle preserved tomato paste compared with industrial counterparts. It  
further evaluates spoilage dynamics and sensory attributes across storage periods. This holistic approach offers  
practical insights into safe, economical, and sustainable tomato processing and preservation strategies applicable  
to Nigeria’s small-scale tomato processing sector (Oladipo et al., 2024).  
The growing preference for locally produced tomato paste underscores the need to scientifically validate its  
safety, nutritional quality, and shelf stability compared to industrial paste. Earlier studies have mainly  
concentrated on compositional or proximate analyses without integrating microbial stability and shelf-life  
assessment under controlled preservation conditions. This study is therefore justified by the necessity to assess  
locally preserved tomato paste, particularly when stored in glass bottles, due to their potential to extend shelf  
life, minimize oxidation, and reduce chemical leaching (Afolabi et al., 2022).  
Furthermore, identifying the range of microorganisms present in both sterile and spoiled tomato paste samples  
during storage will provide critical insights into contamination sources and control points essential for hygienic  
local processing (Eze et al., 2023). The study’s outcomes will also support policy development aligned with  
Nigeria’s food safety and self-sufficiency objectives by promoting small-scale tomato paste production as a  
sustainable agro-based enterprise (SON, 2023).  
The aim to comparatively evaluate the microbial contamination and nutritional composition of locally prepared  
and preserved tomato paste using glass bottles in comparison with industrial tomato paste.  
Specific Objectives  
To determine the microbial load of locally prepared, vendor-preserved, and industrial tomato paste samples over  
a defined storage period.  
To analyze and compare the proximate composition (moisture, ash, protein, ether extract, crude fiber, and  
carbohydrate) of the tomato paste samples.  
To determine the pH, titratable acidity, and vitamin C content of each tomato paste sample during storage.  
To evaluate the sensory characteristics (color, flavor, texture, taste, and overall acceptability) of sterile samples  
throughout storage.  
To compare and interpret the nutritional and microbial variations between sterile and spoiled samples.  
Significance of the Study  
This research provides empirical data on the safety, nutritional value, and overall quality of locally prepared  
tomato paste relative to industrially produced alternatives, thereby contributing to Nigeria’s broader food  
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security and public health agenda (Musa et al., 2023). By identifying microbial and nutritional variations among  
different tomato paste types, the study offers practical guidance for safe processing protocols and best  
preservation practices among local producers (Olaniyi & Ojetayo, 2022).  
Furthermore, the findings will inform policy interventions aimed at regulating local tomato paste production and  
ensuring compliance with national food quality standards as outlined by SON and NAFDAC (SON, 2023). The  
research will also enhance public awareness of hygienic food processing, promote entrepreneurial capacity  
building among small-scale producers, and serve as a scientific foundation for innovative, sustainable food  
preservation methods (Okoro & Aluko, 2023).  
Research Design  
This study employed an experimental comparative research design to evaluate the microbial contamination and  
nutritional composition of four categories of tomato paste stored in glass bottles. The design compared: (i) locally  
prepared tomato paste, (ii) locally prepared paste with added preservatives, (iii) vendor-prepared paste, and (iv)  
industrial tomato paste across different storage durations under controlled laboratory conditions. This approach  
enabled the simultaneous assessment of nutritional stability and microbiological safety, reflecting real-world  
practices of tomato paste storage and preservation (Ijah et al., 2014; Onwuka, 2018).  
The methodology adhered to the standards of the Association of Official Analytical Chemists (AOAC, 2022) for  
all proximate and microbiological analyses. Laboratory preparations were conducted at the Lower Usuma Dam  
Laboratory, Federal Capital Territory, Abuja, while microbial and nutritional analyses were performed at the  
Food Microbiology and Chemistry Laboratory, Nasarawa State University, Keffi. Environmental conditions  
during sample storage and testing were controlled at 25 ± 2°C and relative humidity of 65 ± 5%, ensuring  
consistency across experiments (AOAC, 2022).  
Study Area  
The study was conducted in the Federal Capital Territory (FCT), Abuja, located between latitudes 8.25°N and  
9.20°N, and longitudes 6.45°E and 7.39°E, covering approximately 7,315 km² (Ajibare et al., 2022).  
Sample Procurement and Transportation  
Fresh, red, and firm tomato fruits (Solanum lycopersicum L.), industrial paste, and vendor-prepared tomato  
pastes were procured from local markets in Bwari and Gwagwalada Area Councils, FCT, Abuja. These markets  
were selected due to their high tomato trade volume, accessibility to laboratory facilities, and representation of  
local consumption patterns (FAO, 2021; Eke & Eke, 2024).  
Selection criteria for fresh tomatoes included optimal ripeness (fully red), firmness, absence of visible defects  
(bruises, mold, or pest damage), and uniformity in size to ensure consistency in raw material quality for  
laboratory-based preparation (Adewoye et al., 2021; Muhammad et al., 2023). Immediately after purchase, all  
tomato samples were placed into sterile, insulated cooler boxes containing ice packs to maintain a controlled  
low temperature (2–8°C) during transportation (Amarego & Chai, 2022; WHO, 2020). This rapid cooling was  
critical to minimize microbial proliferation and preserve the physicochemical integrity of the samples during  
transit (Benson, 2019).  
Upon arrival at the laboratory, the raw tomatoes were sorted meticulously to remove damaged or unsuitable  
fruits (Ullah et al., 2021), followed by thorough washing under potable running water to eliminate surface  
contaminants (Al-Hilphy et al., 2020). The cleaned tomatoes were then blended into a smooth purée using a  
sterile blender, creating a uniform base for paste preparation (Chukwuma et al., 2020). Salt was added to the  
purée prior to boiling to enhance flavor and contribute to preservation (Eke et al., 2021). The purée was boiled  
until the desired concentration and Brix level were achieved, then carefully filled into pre-sterilized glass bottles.  
After sealing, the bottles were cooled to room temperature to prevent thermal shock to the glass and preserve  
paste quality (Amadi et al., 2023; Anarbek et al., 2023).  
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Prepared homemade tomato paste samples were stored under specified laboratory conditions for the duration of  
the study.  
Sample Categorization  
The study evaluated four categories of tomato paste prepared.  
Sample Code Description  
HP  
HPP  
VP  
IP  
Home-made preserved tomato paste  
Home-made preserved tomato paste with preservatives (sodium benzoate 0.1%)  
Vendor-prepared preserved tomato paste  
Industrially prepared tomato paste (control)  
All samples were stored in sterilized 250 mL glass bottles, tightly sealed, and maintained at ambient laboratory  
temperature (25 ± 2°C) for a three-month storage period.  
Sample Preparation Procedures  
Locally Prepared Tomato Paste (Home-made Traditionally Preserved)  
Approximately 5 kg of sorted and washed fresh tomatoes were used per triplicate batch. Preparation simulated  
traditional household methods under controlled laboratory conditions:  
Blending: Chopped tomatoes were blended into a smooth purée using a sterile blender (Amadi et al., 2023).  
Boiling and Concentration: The purée was transferred into a sterile stainless-steel pot and boiled over moderate  
heat with continuous stirring to prevent scorching. Boiling continued until the paste reached the desired thick  
consistency, indicated by volume reduction and increased total solids (~1 kg final paste per 5 kg fresh tomatoes)  
(Sani & Dangora, 2021).  
Hot Filling: While still hot (85–90°C), the paste was transferred into pre-sterilized glass bottles, leaving minimal  
headspace.  
Sealing and Cooling: Bottles were tightly sealed and inverted for 5 minutes to sterilize lids and headspace, then  
cooled to ambient temperature before storage (Akinwande & Agboola, 2020).  
Locally Prepared Tomato Paste with Preservative (HPP)  
The procedure followed that of Section 3.5.1, with the addition of sodium benzoate (0.1% w/v) prior to boiling.  
The preservative was incorporated after blending and before heat concentration, ensuring uniform distribution  
and efficacy within the paste (Egbere et al., 2013; NAFDAC, 2023a). Hot filling, sealing, and cooling procedures  
mirrored those described for HP, ensuring standardized laboratory conditions and controlled preservation.  
Vendor-Prepared Tomato Paste (VP)  
Vendor-prepared paste was obtained from multiple local vendors in Bwari and Gwagwalada markets, selected  
based on reputation for hygienically processed food products (Egbunike et al., 2019; Olusanya et al., 2020).  
Triplicate samples from different vendors ensured representation of typical local production variability.  
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Industrial Tomato Paste (IP)  
Commercially manufactured, NAFDAC-registered tomato paste brands were purchased from reputable retail  
outlets and supermarkets in Abuja and used as control samples. These products adhered to industrial standards,  
including quality, microbial safety, and nutritional content (NAFDAC, 2023a; SON, 2019). Triplicate samples  
were purchased, with batch numbers and expiry dates recorded to ensure traceability. Samples remained in  
original packaging until analysis.  
Sampling Strategy  
For this study, tomato paste samples were procured and prepared to ensure uniformity in quality, maturity, and  
freshness across all experimental groups. Fresh tomatoes and paste samples were obtained in bulk without prior  
weighing or counting, with careful visual selection of fruits or paste units that were fully red, firm, and free from  
defects such as bruises, mold, or mechanical damage. For each of the four categories of tomato paste (HP, HPP,  
VP, and IP), three replicate batches (n=3) were prepared or purchased. The use of triplicate samples provided  
sufficient statistical power to enable meaningful comparative analysis of microbiological, nutritional, and  
sensory parameters (Montgomery, 2017).  
The experimental design incorporated two distinct study arms to evaluate product stability and spoilage  
susceptibility:  
a. Sterile Study: Samples were stored under controlled, hygienic laboratory conditions and analyzed at Month  
1 and Month 3 to assess the retention of nutritional quality and microbiological safety over time.  
b. Spoilage Study: Samples were deliberately exposed to ambient laboratory conditions to simulate poor  
storage or handling. These samples were analyzed at Month 3 post-exposure to evaluate the effects of  
microbial contamination on physicochemical properties, nutrient degradation, and shelf-life stability.  
This dual approach allowed the study to compare both ideal and suboptimal storage scenarios, thereby providing  
insights into the safety, quality, and resilience of tomato paste under realistic conditions.  
Laboratory Practices and Good Manufacturing Practices (GMP)  
All laboratory procedures were conducted under strict adherence to established safety protocols, Good  
Laboratory Practices (GLP), and Good Manufacturing Practices (GMP) to ensure personnel safety, prevent  
cross-contamination, and maintain data integrity (WHO, 2020; SON, 2021). All instruments, work surfaces, and  
glassware were sterilized by autoclaving at 121°C for 15 minutes, while analytical equipment such as balances  
and pipettes were calibrated prior to use. Analysts consistently wore laboratory coats, gloves, hair covers, and  
face masks to minimize contamination. Quality control measures included performing triplicate analyses,  
employing control blanks, and verifying media sterility before use (NAFDAC, 2022).  
Aseptic Technique  
Stringent aseptic techniques were employed throughout microbiological analyses to prevent contamination of  
samples and reagents (Benson, 2019). This included:  
Sterilizing all glassware, culture media, and instruments prior to use (Eze et al., 2021).  
Working under laminar flow hoods or biosafety cabinets for all procedures involving microbial cultures (WHO,  
2020).  
Regular disinfection of work surfaces using 70% ethanol before and after experiments (Tchounwou et al., 2021).  
Sterilizing inoculation loops, spatulas, and other contact tools using flaming or single-use sterile alternatives.  
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Minimizing the exposure of samples and reagents to open air during manipulation  
Batches and Storage Times  
A total of 12 experimental sample sets (4 paste types × 3 replicates) were stored under ambient laboratory  
conditions (25–35°C) away from direct sunlight, simulating typical household storage environments in Nigeria  
(Akinwande & Agboola, 2020).  
Sampling Intervals  
Initial Analysis (Month 1): Provided baseline data on the physicochemical, nutritional, and microbiological  
quality immediately post-preparation.  
Final Analysis (Month 3): Assessed stability over extended storage, including changes in microbial load, nutrient  
content, and sensory attributes. Although a six-month storage period was initially planned, logistical constraints  
limited the analysis to three months, which still offered meaningful comparative insights.  
All samples were stored in sterilized glass bottles and analyzed in triplicate (n=3) per batch (AOAC, 2022).  
Microbiological Analysis of Tomato Paste  
Microbiological analysis was performed to assess the safety and quality of tomato paste samples (HP, HPP, VP,  
IP) across storage periods and under spoilage conditions. Standard protocols were followed as outlined by AOAC  
(2022) and WHO (2020) to determine total bacterial count, yeast and mold count, and the presence of common  
pathogens such as Escherichia coli and Salmonella spp.  
Total Viable Count (TVC)  
The Total Viable Count was determined to estimate the overall bacterial load in the samples:  
Sample Preparation: Ten grams (10 g) of tomato paste was aseptically weighed and homogenized in 90 mL of  
sterile distilled water to create a 10-1 dilution. Serial dilutions were prepared up to 10-6 (Hassan et al., 2023).  
Plating: Aliquots (0.1 mL) of appropriate dilutions were spread on sterile Nutrient Agar plates in triplicate.  
Incubation: Plates were incubated at 37°C for 24–48 hours.  
Counting: Colonies were counted, and results expressed in Colony Forming Units per gram (CFU/g) using  
standard calculation methods (FAO/WHO, 2023).  
Yeast and Mold Count  
Fungal contamination was assessed to monitor spoilage potential:  
Media: Potato Dextrose Agar (PDA) supplemented with 0.1 g/L chloramphenicol to inhibit bacterial growth.  
Sample Processing: Ten grams of tomato paste were homogenized in 90 mL sterile distilled water, followed by  
serial dilutions.  
Plating and Incubation: 0.1 mL of appropriate dilutions were spread on PDA plates, incubated at 25–28°C for 3–  
5 days (Blanca et al., 2022).  
Enumeration: Visible fungal colonies were counted and expressed as CFU/g.  
Detection of E. coli and Salmonella spp.  
Pathogenic bacteria were assessed to ensure compliance with WHO, SON, and NAFDAC safety standards:  
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Enrichment: 25 g of tomato paste was pre-enriched in 225 mL of Buffered Peptone Water (BPW) and incubated  
at 37°C for 18–24 hours.  
Selective Plating: Enriched samples were streaked on MacConkey Agar for E. coli and Xylose Lysine  
Deoxycholate (XLD) Agar for Salmonella spp.  
Incubation: Plates were incubated at 37°C for 24–48 hours (El-Shenawy et al., 2022).  
Confirmation: Suspected colonies were subjected to Gram staining, biochemical tests (indole, catalase, oxidase),  
and sugar fermentation tests (Kaur et al., 2023).  
Microbial Analysis Quality Control  
All analyses were performed in triplicates to ensure reproducibility (n=3).  
Sterile media blanks were incubated alongside samples to check for contamination.  
Standard reference strains of E. coli (ATCC 25922) and Salmonella enterica (ATCC 14028) were used as positive  
controls for method validation (WHO, 2020).  
Aseptic techniques were strictly maintained throughout the microbial work to prevent cross-contamination.  
Nutritional Analysis of Tomato Paste  
Nutritional composition analyses included proximate composition, vitamin C content, pH, and titratable acidity.  
All analyses were carried out in accordance with AOAC (2022) standards and performed in triplicates for  
accuracy.  
Proximate Composition  
Moisture Content: Determined by oven-drying 5 g of sample at 105°C until constant weight.  
Crude Protein: Measured using the Kjeldahl method, with nitrogen content multiplied by 6.25.  
Crude Fat: Extracted using Soxhlet extraction with petroleum ether.  
Ash Content: Determined by incinerating 5 g of sample in a muffle furnace at 550°C for 6 hours.  
Crude Fiber: Evaluated by acid and alkali digestion methods.  
Carbohydrates: Calculated by difference from 100% (AOAC, 2022; Amadi et al., 2023).  
Vitamin C Content  
Vitamin C concentration was measured using the 2,6-dichlorophenolindophenol (DCPIP) titrimetric method:  
Sample Preparation: 10 g of paste homogenized in 100 mL of 3% metaphosphoric acid.  
Titration: The extract was titrated with standardized DCPIP solution until a persistent pink endpoint was  
observed.  
Calculation: Vitamin C content expressed as mg/100 g of sample (FAO, 2021).  
pH and Titratable Acidity  
pH: Measured using a calibrated digital pH meter by immersing the electrode into a 10% tomato paste solution.  
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Titratable Acidity: Determined by titrating 10 g of homogenized paste in 50 mL distilled water with 0.1 N NaOH  
using phenolphthalein as indicator. Results expressed as % citric acid equivalent (Kaur et al., 2023).  
Data Analysis  
Data from microbial, nutritional, and sensory analyses were entered into Microsoft Excel and exported to SPSS  
version 25.0 for statistical analysis.  
RESULTS  
were expressed as mean ± standard deviation (SD).  
One-way and two-way ANOVA were used to compare parameters across sample types and storage durations,  
with significance considered at p < 0.05.  
Post-hoc Tukey’s HSD tests were performed for pairwise comparisons where significant differences were  
detected (Montgomery, 2017).  
Analytical Procedures  
All analytical determinations were performed in triplicate, with results expressed as mean ± standard deviation  
(SD) to ensure accuracy and reproducibility.  
Microbial Contamination Analysis  
Microbiological analyses were conducted to quantify bacterial, yeast, and mold populations, following AOAC  
(2022) and ISO protocols (ISO, 2017a–c). Media were prepared according to manufacturer instructions and  
sterilized by autoclaving at 121°C for 15 minutes.  
Media Preparation  
All microbiological media were prepared from dehydrated formulations according to the manufacturer's  
specifications (e.g., Oxoid, HiMedia).  
Plate Count Agar (PCA): A measured quantity of PCA powder (e.g., 23.5 g) was suspended in 1000 mL of  
distilled water, heated gently with stirring until completely dissolved, and then autoclaved at 121°C for 15  
minutes (Benson, 2019). The sterilized medium was cooled to 45-50°C before use.  
MacConkey Agar: A precise amount of MacConkey Agar powder (e.g., 50 g) for coliform detection was  
dissolved in 1000 mL of distilled water by heating with frequent agitation until completely dissolved. The  
medium was then autoclaved at 121°C for 15 minutes. All media were cooled to 45°C-50°C and poured into  
sterile Petri dishes (AOAC, 2022).  
Potato Dextrose Agar (PDA): The required amount of PDA powder (e.g., 39 g) f-or mold and yeast enumeration,  
was suspended in 1000 mL of distilled water, boiled gently to dissolve, and then autoclaved at 121°C for 15  
minutes (ISO, 2017c). For mold and yeast enumeration, the sterilized PDA was cooled to approximately 45°C,  
and then sterile 10% tartaric acid solution was added to adjust the pH to 3.5 to inhibit bacterial growth (Tournas  
& Katsoudas, 2005).  
Nutrient Agar (NA): 28 g/L in distilled water, sterilized at 121°C for 15 minutes.  
Serial Dilution  
1 g of tomato paste was homogenized in 9 mL of sterile distilled water (10⁻¹ dilution).  
Serial dilutions up to 10⁻⁶ were prepared as required.  
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1 mL of each dilution was inoculated into pre-poured sterile agar plates (pour plate method).  
Plates were incubated at 37°C for 24–48 hours (bacteria) and 25–27°C for 3–5 days (fungi) (Benson, 2019; ISO,  
2017a–c).  
Enumeration Procedures  
Total Viable Count (TVC): Counted on PCA; results expressed in CFU/g using the formula: CFU/g = Number  
of Colonies × Dilution Factor ÷ Volume plated.  
Total Coliform Count (TCC): Counted on MacConkey Agar; red colonies with halos were enumerated.  
Yeast and Mold Count: Enumerated on acidified PDA; distinct colonies counted and expressed in CFU/g.  
Nutritional Composition Analysis (Proximate Analysis)  
Proximate analysis was performed according to standard methods of the Association of Official Analytical  
Chemists (AOAC, 2016) to determine the major nutrient components.  
Moisture Content: The moisture content was determined by drying a known weight (approximately 5 g) of each  
paste sample in a pre-weighed, oven-dried crucible at 105°C to a constant weight (AOAC, 2016). The loss in  
weight was calculated as percentage moisture content.  
Ash Content: The ash content was determined by incinerating a known weight (approximately 2 g) of each  
sample in a pre-weighed porcelain crucible in a muffle furnace at 550°C until a constant grayish-white ash was  
obtained (AOAC, 2016). The ash content was expressed as a percentage of the original sample weight.  
Crude Protein (Kjeldahl Method): The crude protein content was determined using the micro-Kjeldahl method  
(AOAC, 2016). A known weight (approximately 2 g) of sample was digested in concentrated sulfuric acid using  
a Kjeldahl digestion unit. The digested sample was then distilled, and the liberated ammonia was collected in  
boric acid solution and titrated against standard hydrochloric acid. A nitrogen conversion factor of 6.25 was used  
to calculate the crude protein content (%), assuming protein contains 16% nitrogen (Nwanekezi et al., 2021).  
Crude Fat (Soxhlet Extraction Method): The crude fat content was determined by extracting a known weight  
(approximately 5 g) of each dried sample using n-hexane as the solvent in a Soxhlet extraction apparatus (AOAC,  
2016). The extraction was carried out for 6 hours. After extraction, the solvent was evaporated, and the remaining  
fat was weighed and expressed as a percentage of the sample (Nwabueze & Nwanekezi, 2021).  
Crude Fiber Content: Crude fiber content was determined by acid and alkaline digestion method (AOAC, 2016).  
A defatted sample (approximately 2 g) was boiled sequentially in dilute sulfuric acid and sodium hydroxide  
solutions, filtered, washed, dried, and ashed. The loss in weight upon ashing represented the crude fiber content  
(%).  
Carbohydrate Content by Difference: The carbohydrate content was calculated by subtracting the sum of the  
percentages of moisture, ash, crude protein, crude fat, and crude fiber from 100 (AOAC, 2016; Amadi et al.,  
2023). Carbohydrate (%) = 100 - (Moisture) % + (Ash) % + (Crude Protein) % + (Crude Fat) % + (Crude Fiber)  
%). All analyses were conducted in triplicate (AOAC, 2022).  
Vitamin C Determination  
Vitamin C (ascorbic acid) content was determined using the titrimetric method with 2,6-  
dichlorophenolindophenol (DCPIP) (AOAC, 2016).  
Extraction: A known weight (e.g., 5-10 g) of tomato paste was accurately weighed and homogenized with 2%  
metaphosphoric acid solution to extract ascorbic acid. The mixture was then filtered.  
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Titration: An aliquot of the filtrate was titrated against a standardized solution of 2,6-dichlorophenolindophenol  
(DCPIP) until a faint pink color persisted for at least 30 seconds (Padayatty et al., 2003).  
Calculation: The amount of Vitamin C was calculated based on the volume of DCPIP consumed and the  
standardization factor, expressed as mg of ascorbic acid per 100 g of sample.  
pH and Titratable Acidity  
pH Measurement: The pH of each tomato paste sample was determined directly using a standardized digital pH  
meter (e.g., Hanna Instruments HI 2210) (Sani & Dangora, 2021). The pH meter was calibrated using buffer  
solutions of pH 4.0 and 7.0 prior to each set of measurements. Approximately 10 g of paste was dispersed in 90  
mL of distilled water, stirred well, and the pH electrode was immersed into the suspension until a stable reading  
was obtained.  
Titratable Acidity (TTA): The titratable acidity was determined by titrating a known volume (e.g., 10 mL) of the  
prepared sample suspension (from pH measurement) against a standardized 0.1 N sodium hydroxide (NaOH)  
solution (AOAC, 2016; Sani & Dangora, 2021). Phenolphthalein indicator was used to detect the endpoint (faint  
pink color persistence). The titratable acidity was expressed as a percentage of anhydrous citric acid, which is  
the predominant acid in tomatoes (Amadi et al., 2023). TTA (% Citric Acid) = V × N × 0.064 × 100 \ Sample  
weight (mL)  
RESULTS AND DISCUSSION  
The outcomes of the study according to the four objectives: (1) proximate composition and vitamin C content of  
the tomato paste samples, (2) physicochemical properties (pH and titratable acidity) during storage and after  
spoilage, (3) microbial load of sterile and intentionally spoiled samples, and (4) sensory attributes as evaluated  
by a consumer panel. Each set of results is interpreted in light of relevant literature. Graphical representation of  
key changes over time is also recommended to enhance clarity.  
Objective 1: Proximate Composition and Vitamin C Content  
Proximate Composition: The proximate composition of the four sterile tomato pastes treatments (HP, HPP, VP,  
IP) at Month 1 and Month 3 is summarized in Table 1a and Table 1b; and Figures 1a–1f).  
Table 1a: Proximate Composition of Sterile Tomato Paste Samples at Month 1 (% Dry Weight Basis, Mean ±  
SD)  
Parameter  
Moisture  
Ash  
HP  
HPP  
VP  
IP  
5.50 ± 0.05c  
8.90 ± 0.05b  
1.91 ± 0.01b  
1.91 ± 0.01b  
1.30 ± 0.01b  
80.48 ± 0.08b  
5.20 ± 0.05b  
9.20 ± 0.05a  
2.10 ± 0.01a  
2.00 ± 0.01a  
1.20 ± 0.01c  
80.30 ± 0.05b  
6.00 ± 0.05a  
8.50 ± 0.05b  
1.80 ± 0.01b  
1.80 ± 0.01b  
1.40 ± 0.01a  
80.50 ± 0.05a  
4.80 ± 0.05c  
9.50 ± 0.05a  
2.30 ± 0.01a  
2.10 ± 0.01a  
1.10 ± 0.01 c  
80.20 ± 0.05 c  
Crude Protein  
Ether Extract  
Crude Fibre  
NFE  
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Table 1b: Proximate Composition of Sterile Tomato Paste Samples at Month 3 (% Dry Weight Basis, Mean ±  
SD)  
Parameter  
Moisture  
Ash  
HP  
HPP  
VP  
IP  
6.20 ± 0.05a  
8.10 ± 0.05b  
1.60 ± 0.01c  
1.70 ± 0.01c  
1.50 ± 0.01a  
79.90 ± 0.08b  
5.90 ± 0.05b  
8.80 ± 0.05a  
1.90 ± 0.01b  
1.80 ± 0.01b  
1.30 ± 0.01b  
79.70 ± 0.05b  
6.80 ± 0.05a  
7.90 ± 0.05b  
1.50 ± 0.01c  
1.50 ± 0.01c  
1.60 ± 0.01a  
79.60 ± 0.08b  
5.00 ± 0.05c  
9.40 ± 0.05a  
2.25 ± 0.01a  
2.05 ± 0.01a  
1.15 ± 0.01 c  
80.15 ± 0.05a  
Crude Protein  
Ether Extract  
Crude Fibre  
NFE  
Figure: 1a showing Proximate Composition of Sterile Tomato Paste Samples at Month 1 (% Dry Weight Basis,  
Mean ± SD)  
Figure: 1b showing Ash Content of Sterile Tomato Paste Samples at Month 1 (% Dry Weight Basis, Mean ±  
SD)  
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Figure: 1c showing Crude Protein Content of Sterile Tomato Paste Samples at Month 1 (% Dry Weight Basis,  
Mean ± SD).  
Figure: 1d showing Ether Extract Content of Sterile Tomato Paste Samples at Month 1 (% Dry Weight Basis,  
Mean ± SD)  
Figure1e showing Crude Fibre Content of Sterile Tomato Paste Samples at Month 1 (% Dry Weight Basis, Mean  
± SD)  
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Figure1f: showing NFE Content of Sterile Tomato Paste Samples at Month 1 (% Dry Weight Basis, Mean ± SD)  
The observed general increase in moisture content across the storage period is consistent with the phenomenon  
of moisture migration or hygroscopic water uptake, which can accelerate the degradation of nutrients and  
compromise the shelf stability of tomato paste (Feszterová et al., 2023). Concurrently, the decline in crude  
protein and ether extract observed in the HP and VP samples indicates that these formulations may be more  
susceptible to nutrient loss under ambient storage conditions, a pattern that has also been reported in other  
tomato-based processed products (Chamoun et al., 2023). Conversely, the observed increase in crude fiber in  
some samples may be attributed to the relative concentration of insoluble components as other macronutrients  
degrade, or to polymerization processes involving pectin and fiber constituents during storage. Notably, the  
superior retention of nutrients in the IP and HPP samples suggests that their specific formulation or processing  
methods provide greater protection against storage-induced nutrient degradation.  
Comparatively, at Month 1, the industrial paste (IP) exhibited the highest crude protein (2.30%) and ether extract  
(2.10%) alongside the lowest moisture content (4.80%), characteristics favorable for a concentrated and stable  
paste. After three months of storage, IP continued to maintain relatively high levels of protein (2.25%) and fat  
(2.05%) with minimal moisture increase (5.00%). HPP also demonstrated good nutrient stability, whereas HP  
and particularly VP displayed lower retention of protein and fat. These findings align with the literature, which  
underscores that both processing techniques and storage conditions critically influence nutrient retention in  
tomato-based products, highlighting the importance of formulation and preservation strategies in extending shelf  
life and maintaining nutritional quality (Alqahtani et al., 2021).  
Vitamin C Content  
Table 2: Vitamin C of Sterile Tomato Paste Samples (mg/100g, Mean ± SD)  
Sample Code  
Month 1  
Month 3  
HP  
HPP  
VP  
IP  
19.52 ± 0.19b  
21.10 ± 0.18a  
17.24 ± 0.13c  
17.24 ± 0.13c  
15.38 ± 0.12c  
18.96 ± 0.14b  
14.11 ± 0.10c  
18.96a ± 0.16b  
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Figure 2.1: Vitamin C of Sterile Tomato Paste Samples (mg/100g, Mean ± SD)  
The observed decline in vitamin C content during storage in HP, HPP, and VP aligns with the well-documented  
susceptibility of ascorbic acid to oxidative degradation, enzymatic activity, and exposure to heat or oxygen over  
time (Feszterová et al., 2023). Notably, the relatively modest decrease in HPP (~10%) and the near-stable, or  
even slightly increased, levels in IP suggest that the industrial formulation provided enhanced protection for  
vitamin C, potentially through lower moisture absorption, minimized oxygen ingress, or the presence of natural  
or added antioxidants. In contrast, VP exhibited the lowest vitamin C concentration at Month 3 (14.11 mg/100  
g), highlighting its comparatively poor storage stability. Collectively, these observations here indicate that,  
among the four treatments, IP maintained the highest overall nutrient and vitamin retention, followed by HPP,  
while HP showed moderate stability and VP performed least favorably. This trend reinforces the critical role of  
formulation, processing, and storage conditions in preserving labile nutrients such as vitamin C in tomato paste  
products (Alqahtani et al., 2021; Chamoun et al., 2023).  
All observed pH values for the tomato paste samples remained within, or closely approached, the safe regulatory  
range established for tomato paste products, supporting both product safety and chemical stability (Salanță et  
al., 2024). The gradual decline in pH over the storage period, such as in HP (4.25 → 4.08) and VP (4.12 → 3.95),  
indicates slight acidification during storage, which may be attributed to residual enzymatic activity, moisture  
migration, or low-level microbial activity even under ostensibly sterile conditions (Feszterová et al., 2023;  
Alqahtani et al., 2021). In contrast, IP maintained a higher pH (~4.32) at Month 3, suggesting superior  
formulation stability and resistance to acidification. The comparatively lower pH observed in VP at the end of  
the storage period may reflect increased acid production or a reduced buffering capacity of the matrix, consistent  
with its lower overall nutrient and vitamin retention. These results highlight the interplay between product  
formulation, processing, and storage conditions in maintaining physicochemical stability of tomato paste.  
Objective 2: Physicochemical Properties (pH and Titratable Acidity)  
pH of Sterile Samples  
Table 2.1: pH of Sterile Tomato Paste Samples (Mean ± SD)  
Sample  
Month 1  
Month 3  
NAFDAC/SON Range  
HP  
4.25 ± 0.05b  
4.30 ± 0.04b  
4.08 ± 0.04b  
4.16 ± 0.03 a  
4.0–4.6  
HPP  
4.0–4.6  
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VP  
IP  
4.12 ± 0.06c  
4.35 ± 0.05a  
3.95 ± 0.05c  
4.32 ± 0.04a  
4.0–4.6  
4.0–4.6  
Figure 2.1: pH of Sterile Tomato Paste Samples (mg/100g, Mean ± SD)  
All pH values lie within or at the safe regulatory range for tomato paste products, which supports product safety  
and stability (Salanță et al., 2024). The observed decline in pH over storage (e.g., HP from 4.25 → 4.08; VP  
from 4.12 → 3.95) suggests slight acidification over time, likely due to residual enzymatic reactions, moisture  
uptake, or minor microbial activity even in “sterile” conditions. IP maintained a higher pH (~4.32) at Month 3,  
implying better formulation stability. VP’s lower pH at Month 3 may reflect increased acid formation or  
decreased buffering capacity.  
Titratable Acidity (TA)  
Table 2.2: Titratable Acidity (TA) of Sterile Tomato Paste Samples (% Citric Acid, Mean ± SD)  
Sample  
Month 1  
Month 3  
HP  
0.42 ± 0.01b  
0.40 ± 0.01b  
0.46 ± 0.01a  
0.38 ± 0.01c  
0.49 ± 0.02a  
0.47 ± 0.02a  
0.52 ± 0.02a  
0.40 ± 0.01b  
HPP  
VP  
IP  
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Figure 4.2.2: Titratable Acidity of Sterile Tomato Paste Samples (mg/100g, Mean ± SD).  
The observed increase in titratable acidity (TA) during storage, for instance HP (0.42 → 0.49%), HPP (0.40 →  
0.47%), and VP (0.46 → 0.52%), reflects progressive acidification of the tomato paste over time. This trend is  
consistent with the enzymatic or chemical conversion of residual carbohydrates into organic acids, moisture  
migration, and oxidative processes during storage (Vieira et al., 2022; Feszterová et al., 2023). In contrast, IP  
exhibited the smallest increase in TA (0.38 → 0.40%), suggesting that its formulation or processing effectively  
mitigated acidification, possibly through reduced oxygen ingress, lower moisture uptake, or stabilizing additives.  
The higher TA observed in VP aligns with its comparatively lower pH at Month 3, reinforcing that this sample  
underwent more pronounced acidification. From a quality and shelf-stability perspective, maintaining stable pH  
and TA values is critical, and IP demonstrates superior performance in this regard. These findings underscore the  
importance of formulation and processing parameters in preserving the physicochemical stability of tomato paste  
during ambient storage.  
Objective 3: Microbial Load of Sterile and Intentionally Spoiled Samples  
Table 4.3.1 gives microbial counts (CFU/g) for bacteria, moulds and yeasts in the sterile samples at Month 1  
and Month 3 (CFU/g, Mean ± SD).  
Parameter  
Bacteria  
Sample  
HP  
Month 1 Mean ± SD  
1.1 ± 0.1 × 10 2b  
0.9 ± 0.1 × 10 2b  
1.5 ± 0.1 × 10 2c  
0.5 ± 0.1 × 10 2a  
5 ± 1b  
Month 3 Mean ± SD  
1.4 ± × 0.1 ×10 2c  
1.1 ± 0.1 × 10 2b  
1.7 ± 0.1 × 10 2d  
0.6 ± 0.1 × 10 2a  
6 ± 1c  
HPP  
VP  
IP  
Molds  
HP  
HPP  
VP  
4 ± 1b  
4 ± 1b  
7 ± 1c  
8 ± 1d  
IP  
2 ± 1a  
3 ± 1a  
Yeast  
HP  
8 ± 1c  
9 ± 1c  
HPP  
6 ± 1b  
7 ± 1b  
VP  
IP  
10 ± 1d  
3 ± 1a  
11 ± 1d  
4 ± 1a  
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Figure: 3a showing bacteria load of Sterile Tomato Paste Samples at Month 1 (% Dry Weight Basis, Mean ±  
SD)  
Figure: 3b showing mold load of Sterile Tomato Paste Samples at Month 1 (% Dry Weight Basis, Mean ± SD)  
Figure: 3c showing yeast load of Sterile Tomato Paste Samples at Month 1 (% Dry Weight  
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Basis, Mean ± SD)  
The microbial loads across all samples remained generally low but demonstrated incremental increases during  
storage, with VP exhibiting the highest counts and IP showing the smallest changes. This pattern suggests that  
even under ostensibly “sterile” processing conditions, ambient storage can permit limited microbial proliferation,  
and that the formulation, packaging, and storage conditions significantly influence the extent of growth. Factors  
such as moisture uptake, minor pH shifts, and the integrity of sealing or packaging have been shown to affect  
microbial stability in tomato-based products (Alkanan et al., 2021; Chamoun et al., 2023). The relatively minimal  
microbial increase in IP and HPP indicates that their processing and preservation methods provide more effective  
microbial control, whereas VP’s higher counts may reflect suboptimal handling, higher residual moisture, or  
compromised packaging. These findings align with previous studies emphasizing the critical role of product  
formulation, hygienic processing, and storage conditions in controlling microbial contamination and ensuring  
product safety in tomato paste (Eze et al., 2021; Igwegbe et al., 2020).  
Figure 2.2: Titratable Acidity of Sterile Tomato Paste Samples (mg/100g, Mean ± SD).  
DISCUSSION  
The observed increase in titratable acidity (TA) during storage, for instance HP (0.42 → 0.49%), HPP (0.40 →  
0.47%), and VP (0.46 → 0.52%), reflects progressive acidification of the tomato paste over time. This trend is  
consistent with the enzymatic or chemical conversion of residual carbohydrates into organic acids, moisture  
migration, and oxidative processes during storage (Vieira et al., 2022; Feszterová et al., 2023). In contrast, IP  
exhibited the smallest increase in TA (0.38 → 0.40%), suggesting that its formulation or processing effectively  
mitigated acidification, possibly through reduced oxygen ingress, lower moisture uptake, or stabilizing additives.  
The higher TA observed in VP aligns with its comparatively lower pH at Month 3, reinforcing that this sample  
underwent more pronounced acidification. From a quality and shelf-stability perspective, maintaining stable pH  
and TA values is critical, and IP demonstrates superior performance in this regard. These findings underscore the  
importance of formulation and processing parameters in preserving the physicochemical stability of tomato paste  
during ambient storage.  
Table 4.3.1 gives microbial counts (CFU/g) for bacteria, moulds and yeasts in the sterile samples at Month 1  
and Month 3 (CFU/g, Mean ± SD).  
Parameter  
Bacteria  
Sample  
HP  
Month 1 Mean ± SD  
1.1 ± 0.1 × 10 2b  
0.9 ± 0.1 × 10 2b  
1.5 ± 0.1 × 10 2c  
Month 3 Mean ± SD  
1.4 ± × 0.1 ×10 2c  
1.1 ± 0.1 × 10 2b  
1.7 ± 0.1 × 10 2d  
HPP  
VP  
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IP  
0.5 ± 0.1 × 10 2a  
5 ± 1b  
0.6 ± 0.1 × 10 2a  
6 ± 1c  
Molds  
Yeast  
HP  
HPP  
VP  
IP  
4 ± 1b  
4 ± 1b  
7 ± 1c  
8 ± 1d  
2 ± 1a  
3 ± 1a  
HP  
HPP  
VP  
IP  
8 ± 1c  
9 ± 1c  
6 ± 1b  
7 ± 1b  
10 ± 1d  
3 ± 1a  
11 ± 1d  
4 ± 1a  
Figure:3a showing bacteria load of Sterile Tomato Paste Samples at Month 1 (% Dry Weight Basis, Mean ± SD)  
Figure: 3b showing mold load of Sterile Tomato Paste Samples at Month 1 (% Dry Weight Basis, Mean ± SD)  
Figure: 3c showing yeast load of Sterile Tomato Paste Samples at Month 1 (% Dry Weight  
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Basis, Mean ± SD)  
The microbial loads across all samples remained generally low but demonstrated incremental increases during  
storage, with VP exhibiting the highest counts and IP showing the smallest changes. This pattern suggests that  
even under ostensibly “sterile” processing conditions, ambient storage can permit limited microbial proliferation,  
and that the formulation, packaging, and storage conditions significantly influence the extent of growth. Factors  
such as moisture uptake, minor pH shifts, and the integrity of sealing or packaging have been shown to affect  
microbial stability in tomato-based products (Alkanan et al., 2021; Chamoun et al., 2023). The relatively minimal  
microbial increase in IP and HPP indicates that their processing and preservation methods provide more effective  
microbial control, whereas VP’s higher counts may reflect suboptimal handling, higher residual moisture, or  
compromised packaging. These findings align with previous studies emphasizing the critical role of product  
formulation, hygienic processing, and storage conditions in controlling microbial contamination and ensuring  
product safety in tomato paste (Eze et al., 2021; Igwegbe et al., 2020).  
Table 8: Microbial Load of Spoiled Tomato Paste Samples at Month 3 (CFU/g, Mean ± SD)  
Parameter  
Bacteria  
Sample  
HP  
Month 3 Mean ± SD  
0.7 ± × 0.2 ×103b  
2.5 ± 0.1 × 103b  
3.5 ± 0.1 × 106d  
1.0 ± 0.1 × 10 2a  
1.5 ± × 0.1 ×103b  
2.0 ± 0.1 × 102a  
1.0 ± 0.05 × 105c  
<10a  
HPP  
VP  
IP  
Molds  
Yeast  
HP  
HPP  
VP  
IP  
HP  
1.4 ± 0.1 × 102a  
2.1 ± 0.1 × 103b  
1.0 ± 0.1 × 105c  
<10a  
HPP  
VP  
IP  
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Figure:3.2a showing bacteria of Spoiled Tomato Paste Samples at Month 1 (% Dry Weight Basis, Mean ± SD).  
Figure: 3.2b showing molds of Spoiled Tomato Paste Samples at Month 1 (% Dry Weight Basis, Mean ± SD)  
Figure: 3.2c showing yeast of Spoiled Tomato Paste Samples at Month 1 (% Dry Weight Basis, Mean ± SD).  
The spoilage experiment highlights pronounced differences in microbial susceptibility among the four tomato  
paste samples. VP was highly prone to microbial proliferation, reaching bacterial counts of approximately 3.5 ×  
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10⁶ CFU/g, whereas IP demonstrated remarkable resistance, with mold/yeast counts below 10 CFU/g and  
bacterial counts around 1 × 10² CFU/g. This stark contrast underscores the critical role of formulation,  
processing, and storage conditions in determining microbial safety and spoilage dynamics. Factors such as higher  
residual moisture, inadequate acidification, and compromised packaging integrity in VP likely facilitated  
accelerated microbial growth (Vieira et al., 2022; Igwegbe et al., 2020). Conversely, the low microbial  
proliferation in IP indicates that its formulation and processing effectively inhibited microbial contamination,  
likely through reduced moisture uptake, optimal acidity, and proper sealing. The extremely high microbial load  
observed in VP would pose a significant safety risk if the product were produced and distributed commercially,  
highlighting the necessity for strict quality control, hygienic processing, and appropriate storage practices to  
prevent spoilage and ensure consumer safety (Eze et al., 2021; Alkanan et al., 2021).  
CONCLUSION  
This study concludes that glass-bottle preservation of tomato paste can effectively sustain microbial safety,  
nutritional integrity, and sensory acceptability comparable to industrial paste when adequate sterilization and  
hygienic procedures are maintained (Ibrahim et al., 2023).  
The comparative assessment between sterile and spoilage studies established that the inclusion of natural  
preservatives and proper sealing significantly enhanced product stability under ambient Nigerian conditions  
(Umar & Yusuf, 2023).  
Home and vendor-preserved samples without stringent processing controls were more susceptible to microbial  
spoilage and nutrient degradation, underscoring the importance of standardized heat treatment and airtight  
packaging (Ajayi & Ogunyemi, 2022).  
Therefore, local production of glass-bottled tomato paste, if regulated to meet SON/NAFDAC standards, offers  
a viable pathway to reducing postharvest losses, enhancing nutrition security, and promoting small-scale agro-  
processing industries in Nigeria (Okonkwo & Eze, 2024).  
This study provides new evidence that locally prepared and glass-bottle-preserved tomato paste can maintain  
nutritional and microbiological quality comparable to industrially processed paste when sterilization and  
preservation procedures are properly controlled (Mohammed et al., 2023).  
Unlike earlier works that focused mainly on industrial formulations, this research demonstrated that home-level  
preservation especially with mild preservatives can sustain proximate stability and microbial safety for up to  
three months under Nigerian ambient conditions (Umar & Yusuf, 2023).  
The study also introduces a comparative experimental framework that integrates sterile and intentionally spoiled  
samples, providing a more holistic view of post-processing deterioration mechanisms in tomato paste systems  
(Nguyen et al., 2022).  
By aligning results with NAFDAC and SON microbiological thresholds, the research offers a scientific  
benchmark for quality assurance applicable to small-scale tomato processors in Nigeria (Adeleke et al., 2023).  
Furthermore, the generated baseline data on nutrient retention and microbial dynamics can serve as a reference  
for future formulation optimization, shelf-life modeling, and regulatory standardization within the agro-  
processing value chain (Liang et al., 2023).  
RECOMMENDATIONS  
Based on the results, several practical and policy-level recommendations are advanced.  
First, local producers of tomato paste should adopt standardized sterilization techniques—such as wet-heat  
processing at controlled temperatures and durations—to minimize microbial contamination and extend shelf life  
(Ogunbanwo et al., 2023).  
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Second, the use of transparent glass bottles should be coupled with light-protective storage to limit vitamin C  
oxidation and pigment fading (Salunkhe & Kadvekar, 2023).  
Third, small-scale processors should be trained through agricultural extension services on good manufacturing  
practices (GMP), safe handling, and hygienic bottling procedures to meet SON/NAFDAC specificat ions  
(Okonkwo & Eze, 2024).  
Fourth, policymakers should encourage investment in community-level tomato preservation clusters equipped  
with autoclaves and heat-sealers to support rural value-addition and reduce postharvest losses (Abubakar &  
Oladipo, 2023).  
Finally, consumer awareness campaigns are needed to promote acceptance of locally produced, safely preserved  
tomato paste as a cost-effective and nutritious alternative to imported brands (Duodu et al., 2023).  
CONCLUSION  
This study concludes that glass-bottle preservation of tomato paste can effectively sustain microbial safety,  
nutritional integrity, and sensory acceptability comparable to industrial paste when adequate sterilization and  
hygienic procedures are maintained (Ibrahim et al., 2023).  
The comparative assessment between sterile and spoilage studies established that the inclusion of natural  
preservatives and proper sealing significantly enhanced product stability under ambient Nigerian conditions  
(Umar & Yusuf, 2023).  
Home and vendor-preserved samples without stringent processing controls were more susceptible to microbial  
spoilage and nutrient degradation, underscoring the importance of standardized heat treatment and airtight  
packaging (Ajayi & Ogunyemi, 2022).  
Therefore, local production of glass-bottled tomato paste, if regulated to meet SON/NAFDAC standards, offers  
a viable pathway to reducing postharvest losses, enhancing nutrition security, and promoting small-scale agro-  
processing industries in Nigeria (Okonkwo & Eze, 2024).  
This study provides new evidence that locally prepared and glass-bottle-preserved tomato paste can maintain  
nutritional and microbiological quality comparable to industrially processed paste when sterilization and  
preservation procedures are properly controlled (Mohammed et al., 2023).  
Unlike earlier works that focused mainly on industrial formulations, this research demonstrated that home-level  
preservation especially with mild preservatives can sustain proximate stability and microbial safety for up to  
three months under Nigerian ambient conditions (Umar & Yusuf, 2023).  
The study also introduces a comparative experimental framework that integrates sterile and intentionally spoiled  
samples, providing a more holistic view of post-processing deterioration mechanisms in tomato paste systems  
(Nguyen et al., 2022).  
By aligning results with NAFDAC and SON microbiological thresholds, the research offers a scientific  
benchmark for quality assurance applicable to small-scale tomato processors in Nigeria (Adeleke et al., 2023).  
Furthermore, the generated baseline data on nutrient retention and microbial dynamics can serve as a reference  
for future formulation optimization, shelf-life modeling, and regulatory standardization within the agro-  
processing value chain (Liang et al., 2023).  
RECOMMENDATIONS  
Based on the results, several practical and policy-level recommendations are advanced.  
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First, local producers of tomato paste should adopt standardized sterilization techniques—such as wet-heat  
processing at controlled temperatures and durations—to minimize microbial contamination and extend shelf life  
(Ogunbanwo et al., 2023).  
Second, the use of transparent glass bottles should be coupled with light-protective storage to limit vitamin C  
oxidation and pigment fading (Salunkhe & Kadvekar, 2023).  
Third, small-scale processors should be trained through agricultural extension services on good manufacturing  
practices (GMP), safe handling, and hygienic bottling procedures to meet SON/NAFDAC specifications  
(Okonkwo & Eze, 2024).  
Fourth, policymakers should encourage investment in community-level tomato preservation clusters equipped  
with autoclaves and heat-sealers to support rural value-addition and reduce postharvest losses (Abubakar &  
Oladipo, 2023).  
Finally, consumer awareness campaigns are needed to promote acceptance of locally produced, safely preserved  
tomato paste as a cost-effective and nutritious alternative to imported brands (Duodu et al., 2023).  
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