1.1 Introduction
The wide array of available dairy foods challenges the microbiologist, engineer, and technologist to find the best ways to prevent the entry of micro-organisms, destroy those that do get in along with their enzymes, and prevent the growth and activities of those that escape processing treatment. Troublesome spoilage micro-organisms include aerobic psychrotrophic Gram negative bacteria, yeasts, molds, heterofermentative, lactobacilli, and Spore-forming bacteria psychrotrophic extracellular hydrolytic enzymes, and the extend of recontamination of pasteurized fluid milk products with these bacteria is a major determinant of their shelf life. Fungal spoilage of dairy food is manifested by the presence of a wide variety of metabolic by-products, causing off-odors in color or texture. Coliforms, Yeasts, heterofermentative lactic acid bacteria, defects in cheeses. The rate of spoilage of much dairy food is slowed by the application of one or more of the following treatments, of one or more of the following treatments, reducing the Ph by fermenting the lactose to lactic and adding acids or other approved preservatives. The type of spoilage microorganisms differs widely among, dairy foods because of the selective effects of practices followed in production formulation, processing, packaging storage, distribution, and handling (Loralyn H. Ledenbach and Robert T. Marshall 2005).
1.2 Background of Study
Liquid Canned Milk (Peak Milk) is a rich source of macro and micronutrients (Jalili-Nik et al., 2018). Milk can be classified based on the types of treatment they undergo, which include raw milk (unpasteurized), market milk (pasteurized fluid milk), dried milk powder and concentrated milk such as unsweetened condensed and sweetened condensed milks (Roberts et al., 2005). Milk provides a suitable source of energy and high quality protein including a number of essential micronutrients like zinc, potassium, magnesium, calcium and phosphorus (Gorska-Warsewicz et al., 2019). Thus, it can serve as a suitable growth medium for microorganisms.
Milk composition and microbial load are essential factors that must be considered in assessing quality of milks because these factors affect processing of milks and their nutritional quality and safety (Flint et al., 2020). Powdered milk supports growth of bacteria, including Staphylococcus (S.) aureus; Enterococcus, Micrococcus, Streptococcus, Bacillus and Clostridium spp. as well as several other microorganisms (Pal et al., 2016). Other common contaminants in milk and milk products include Escherichia (E.) coli and Lactobacillus spp. (Kivanc et al., 2019). Bacterial growth in milk media is enhanced under conditions such as adequate water activity, favorable pH and adequate temperature (Sadhu, 2018).
The major bacteriological medium used in routine assays for the quality assessment of dairy products is milk agar. Various types of milk media include peptonized milk, litmus milk media, skim milk powder and milk agar. As stated in the Product Catalog of the Becton Dickinson Diagnostics Systems, International Dairy Federation and British Standards Institute have published recommendations for the use of milk agar in microbial analysis of dried milk, liquid milk, whey and ice cream and whey. For Oxoid milk agar, constituents include yeast extract (3 g), peptone (5 g), milk solids (1 g) and agar (15 g) as specified in Oxoid Manual. Yeast extract and peptone provide essential nutrients while agar is a solidifying agent. Culture media include various compositions to provide growth require- ments of certain culture species (Ryan et al., 2004). Complex media usually include components such as yeast extract, meat extract and peptone. Most of the media currently used in laboratories are imported and thus there is a need to use local substitutes that are abundant and available for the development of appropriate economic media in developing countries (Esan et al., 2009). Presently, imported milk media such as milk agar (500 g) costs nearly $ 200 on the average with no trans- portation/shipment costs. Thus, it is necessary to substitute compounds with similar results since milk media are expensive and not easily available. Therefore, this study assessed growth of common contaminants of dairy products, including S. aureus, E. coli and Lactobacillus spp. on compounded milk agar (CMA) using popular milk brands and readily available cheap protein substitutes independently and wholly, compared to nutritional and microbial growth enhancement qualities of imported milk agar (IMA).
1.3 Statement of Problems
Investigation reveals the problems of the Microbial Analysis of Expired Canned Food Product (Liquid Canned Milk) research work;
- A lot of people suffer from diabetes as a result of excessive Liquid Canned Milk (Peak Milk) intake,
- Insufficient information relating to the Proximate Analysis of Liquid Canned Milk (Peak Milk) Determination of Moisture Content
- Lack of proper examination of the imported milk agar and compounded milk agar
- Inadequate analysis of microbiological content of Liquid Canned Milk (Peak Milk).
1.4 Aim and Objectives of Study
The aim of the study is to analyze the Microorganism in Expired Liquid Canned Milk. In achieving this aim, the following specific objectives were set out as follows;
- To determine the presence of Micro-organism in expired canned milk product and it’s effect in human system.
- To determine the Proximate analyses of the imported milk agar and compounded milk agar with various protein sources
- To assess the microbiological examination of Liquid Canned Milk (Peak Milk) Isolation of Bacteria from Liquid Canned Milk (Peak Milk)
- To examine of Total Bacteria, and Coliform Bacteria from Liquid Canned Milk (Peak Milk)
1.5 Justification of Study
Milk’s healthfulness depends on the individual and the type of milk they consume. Pasteurized milk that is high in protein, low in fat, and free from unnecessary additives can be healthful for many people. On the other hand, some flavored milks contain as much sugar as a can of soda. These are not a healthful choice. Present day cow’s milk is not a single product. It can be fresh or long life, fat free, lactose free, fortified with added omega-3s, hormone free, organic, or raw, among other options. The nutritional breakdown of milk depends on the fat content and whether or not the manufacturer has enriched it. Milk’s nutrients can benefit the body in various ways. The sections below discuss the specific health benefits of milk in more detail. Milk can be good for the bones because it provides vitamin D and calcium. In fact, it may help prevent osteoporosis and adequate vitamin D levels support the production of serotonin, a hormone associated with mood, appetite, and sleep. A diet that includes an adequate amount of protein can enhance wound healing, and it may lead to an increase in muscle mass. It may also promote weight loss, but further studies are needed to confirm this. People who wish to lose weight should opt for skim or low fat milk, and they should be mindful of their total daily calorie intake if consuming full fat milk (Medicalnewstoday, 2021).
Besides, the study will serve as reference material for subsequent researcher in the field or related topics.
1.6 Scope of Study
The study focuses on the Microbial Analysis of Expired Canned Food Product (Liquid Canned Milk) which comprises the proximate analyses of the imported milk agar and compounded milk agar with various protein sources, and Elemental analyses of the imported milk agar and compounded milk agar.
1.7 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Research material: availability of research material is a major setback to the scope of the study.
- Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials.
