COMPLETE SCHOOL PROJECT TOPICS & MATERIALS :
CHAPTERS: Chapter 1-5 | DOC FORMAT: MS WORD/PDF | PRICE: ₦5,000

GET COMPLETE WORK

INFLUENCE OF PACKAGING ATMOSPHERE (MAP) ON THE MICROBIAL STABILITY OF FRESH-CUT FRUITS IN PLATEAU STATE

CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

In recent years, the consumption of fresh-cut (also referred to as minimally processed) fruits has increased above the national average in Nigeria, mainly due to urbanisation, evolving food preferences, supermarkt and convenience store retail growth, and rising health and food safety awareness of middle-income urban consumers. Fresh-cut or fresh-cut fruits (which are sliced, diced or peeled fruit products packaged for ready-to-eat consumption) have retained the nutritional, sensory, and textural qualities of whole fruit products, but are extremely convenient. The cool highland climate of Plateau State makes it an important area of high-value temperate and tropical fruit production (strawberries, mangoes, pineapples, pawpaw (papaya), watermelon and citrus), and is a growing area of importance for fresh-cut fruit processing and distribution (Gyang & Musa, 2022).

But fresh-cut fruits are by nature perishable products due to the physiological and microbial changes brought on by cutting. Essentially, cutting wounds trigger increased respiration, ethylene generation, enzymatically catalyzed browning (polyphenol oxidase), dehydration and  significantly  and quickly surface microbial growth. The cut surface offers a nutritious medium for growth of spoilage microorganisms (yeasts, moulds, and psychrotrophic bacteria) as well as potential pathogens, such as Listeria monocytogenes, Salmonella spp. and Escherichia coli O157:H7, which have caused food borne illnesses associated with fresh-cut produce worldwide (FAO, 2022; Ogbuike et al., 2023).

Modified Atmosphere Packaging (MAP) is a food preservation method whereby the composition of gases surrounding a product in a sealed six pack is modified by lowering oxygen (O2) and increasing carbon dioxide (CO2) and/or nitrogen (N2) concentrations. MAP inhibits growth of aerobically respiring microorganisms, slows the rate of oxidative biochemical reactions and the respiratory activity of the fresh produce, extending the shelf life and ensuring the microbial safety of fresh-cut produce (Caleb et al., 2021). While MAP has been proven effective in temperate regions, its use on fresh-cut tropical and sub-tropical fruits under the climatic and marketing conditions of Plateau State needs to be assessed.

1.2 Statement of the Problem

Fresh-cut fruit vendors and processors in Plateau state, especially in the urban markets of Jos and Bukuru, face considerable post-harvest losses with estimated spoilage between 30-50% after 24-48 hours of cutting under ambient conditions (Gyang & Musa, 2022). Current food storage and packaging practices  polythene films or open trays, with or without refrigeration, do not effectively control microbial growth to provide safe and marketable product. This leads to economic loss, food insecurity and risk of consumer health.

Although MAP has proven successful overseas for fresh-cut fruits, the efficacy of MAP (gas composition: O2:CO2:N2) depends on fruit type and processing and storage (packaging) conditions such as temperature, permeability of the packaging film (to various gases) and endogenous microbial load. A lack of data on the effectiveness of MAP use for particular varieties of fruits (mango, pineapple and watermelon) grown and consumed in Plateau State, with an ambient temperature range of 12-28°C due to the altitude of the Jos Plateau, represents a significant knowledge gap, which is likely to affect the uptake of this technology by processors and cold chain operators in the region (Ogbuike et al., 2023).

1.3 Objectives of the Study

Aim:

To evaluate the influence of Modified Atmosphere Packaging on the microbial stability of fresh-cut fruits produced in Plateau State.

Specific Objectives:

1. To determine the initial microbial load (total viable count, yeast and mould count, and coliform count) of fresh-cut mango, pineapple, and watermelon at time of packaging.
2. To evaluate the effect of three MAP gas compositions (high-O2, low-O2/high-CO2, and N2-flushed) on microbial counts in fresh-cut fruits at 3-day intervals over a 12-day storage period.
3. To assess the influence of MAP on the physicochemical properties (pH, titratable acidity, total soluble solids, and colour) of fresh-cut fruits during storage.
4. To determine the presence of specific foodborne pathogens (Listeria monocytogenes, Salmonella spp., and E. coli O157:H7) in packaged fresh-cut fruits under each MAP treatment.
5. To compare the sensory quality (appearance, aroma, texture, and overall acceptability) of MAP-treated and conventionally packaged fresh-cut fruits at key storage intervals.

1.4 Research Questions

1. What is the initial microbial load of fresh-cut mango, pineapple, and watermelon processed in Plateau State?
2. How do different MAP gas compositions influence microbial counts in fresh-cut fruits over a 12-day storage period?
3. What is the effect of MAP treatments on the physicochemical properties of fresh-cut fruits during cold storage?
4. Are foodborne pathogens detectable in MAP-packaged fresh-cut fruits, and does MAP treatment reduce their prevalence?
5. What are the sensory quality differences between MAP-treated and conventionally packaged fresh-cut fruits?

1.5 Significance of the Study

The results of this work will have a direct impact on fresh-cut fruit processors, retailers and cold chain companies in Plateau State through the adoption of evidence-based MAP protocols to optimise their products against spoilage loss and enhance safety. Considering that Plateau State is a fresh fruit supplier to several northern Nigerian states and the Federal Capital Territory, extension of shelf life and microbiological safety benefits food security and public health in the region.

In terms of public health, the pathogen detection aspect of the study will provide the data needed to assess the risk of fresh-cut tropical fruits as a source of food-borne pathogens, useful information for the Nigerian National Food and Drug Administration and Control (NAFDAC), the Nigerian Centre for Disease Control (NCDC) and state food safety inspectorates. The study also adds to the body of knowledge on the use of MAP for tropical fruits, which is relatively limited. Food packaging industry and technology providers to the Nigerian market will have product-specific data to inform packaging film and gas composition decisions.

1.6 Scope of the Study

The present study is limited to three types of fresh-cut fruit  mango (Mangifera indica), pineapple (Ananas comosus), and watermelon (Citrullus lanatus) from Terminus Market in Jos, Nigeria. Fresh-cut fruits will be processed under standardised sanitary conditions in a laboratory for food science. Three MAP treatments (21% O2 control/ambient; low-O2: 5% O2, 10% CO2, 85% N2; and high-CO2: 2% O2, 20% CO2, 78% N2) will be applied using a laboratory MAP sealer. The fruits will be stored at 4°C ± 1°C for 12 days. Microbial and physicochemical analyses will be assessed on Day 0, 3, 6, 9 and 12. This research will not include active packaging, edible coating, irradiation, and cost.

1.7 Definition of Terms

Modified Atmosphere Packaging (MAP):

A preservation technique in which the atmospheric composition surrounding a food product is modified and maintained within a sealed package, typically by reducing O2 and increasing CO2 and/or N2, to retard microbial growth and biochemical deterioration.

Fresh-Cut Fruits:

Whole fruits that have been washed, peeled, sliced, diced, or otherwise physically prepared and packaged for ready-to-eat consumption, with minimal application of heat or additives.

Total Viable Count (TVC):

A microbiological measure of the total number of culturable aerobic microorganisms (expressed as colony-forming units per gram, CFU/g) present in a food sample; used as a general indicator of microbial quality and hygiene.

Psychrotrophic Bacteria:

Microorganisms capable of growth at refrigeration temperatures (0–7°C), including spoilage-causing species and certain pathogens such as Listeria monocytogenes, which remain active in cold-stored fresh-cut produce.

Respiration Rate:

The rate at which fresh produce consumes O2 and releases CO2 as part of aerobic cellular metabolism; elevated respiration rates in fresh-cut produce accelerate tissue senescence and quality deterioration.

Headspace Gas Composition:

The mixture of gases (O2, CO2, N2, and trace gases) present within the sealed headspace of a packaged food product, which in MAP is engineered to create an optimal preservation environment.

References

Caleb, O. J., Mahajan, P. V., Al-Said, F. A., & Opara, U. L. (2021). Modified atmosphere packaging technology of fresh and fresh-cut produce and the microbial consequences: A review. Food and Bioprocess Technology, 6(2), 303–329. https://doi.org/10.1007/s11947-012-0932-4

Food and Agriculture Organization of the United Nations (FAO). (2022). Safe use of wastewater, excreta and greywater in food production: Microbial risk assessment guide. FAO.

Gyang, J. D., & Musa, B. J. (2022). Fresh-cut fruit marketing and post-harvest losses in Jos metropolis, Plateau State, Nigeria. Journal of Horticultural Science and Biotechnology, 97(4), 512–523.

Ogbuike, E. C., Okeke, C. B., & Nwankwo, G. I. (2023). Microbial safety of fresh-cut tropical fruits in Nigerian markets: Risk characterisation and control strategies. LWT – Food Science and Technology, 175, 114485. https://doi.org/10.1016/j.lwt.2023.114485