CHAPTER ONE

INTRODUCTION

Food hygiene is a broad subject. It covers all the conditions and measures needed to ensure that food is safe and suitable for human consumption at every stage of the food chain, from production, collection and transport to storage, preparation, sale and consumption (Codex Alimentarius Commission, 2020). Foodborne illness is a disease, usually infectious or toxic in nature, caused by agents that enter the body through the ingestion of food. Food safety is the discipline concerned with handling, preparing and storing food in ways that prevent such illness. In kitchen practice it means storing food items properly before use, keeping the preparation area clean, and making sure that utensils and serving dishes are clean and free of bacteria. Mixing bowls, spoons, knives and other tools should be washed thoroughly before use, and work surfaces and cutting boards should be cleaned and disinfected regularly. Food can pass disease from one person to another, and it can also serve as a growth medium for bacteria that cause food poisoning.

Food contamination most commonly occurs through faecal–oral transmission, for example from contaminated fingers or flies. It may also occur through skin infections on the hands of food vendors, as in staphylococcal food poisoning, through the consumption of diseased animals, or through chemicals such as pesticides on crops. Food poisoning is, in principle, entirely preventable.

Everyone is at risk of foodborne illness, but the burden is not evenly spread. According to the World Health Organization (WHO), unsafe food causes about 600 million cases of foodborne disease and 420,000 deaths each year, and 30% of foodborne deaths occur among children under 5 years of age (WHO, n.d.). The African and South-East Asian regions have the highest burden, and the risk is greatest in low- and middle-income countries, where it is linked to food prepared with unsafe water, poor hygiene, inadequate conditions in food production and storage, lower levels of literacy and education, and weak food safety legislation or enforcement (WHO, n.d.). Consumers reasonably expect that the food they buy has been produced and processed hygienically and has not been contaminated with any biological, chemical or physical hazard. In most countries these expectations are backed by regulations governing the production, processing, distribution and sale of food, and in Nigeria this task is carried out by the National Agency for Food and Drug Administration and Control (NAFDAC).

Because so much depends on how food is handled, WHO has summarised the essentials of food hygiene in its “Five Keys to Safer Food” (WHO, 2006):

1. Keep clean: prevent contamination of food by pathogens spreading from people, pets and pests.
2. Separate raw and cooked food, so that cooked food is not contaminated.
3. Cook food thoroughly, for the right length of time and at the right temperature, to kill pathogens.
4. Keep food at safe temperatures.
5. Use safe water and safe raw materials.

Problem Statement

Food is the one substance that every human being must consume, so contamination anywhere along the food chain can have far-reaching and sometimes fatal consequences. Foodborne illness is a burden to individuals, who suffer sickness, discomfort and loss of income, and to health services, industry and commerce, since it strains health systems and disrupts business (WHO, n.d.). The disease burden is estimated at 33 million years of healthy life lost each year, which is probably an underestimate (WHO, n.d.). Diarrhoeal diseases, a large share of which are foodborne, cause malnutrition in infants and young children, and the high prevalence of such disease in many developing countries points to major underlying food safety problems (WHO, n.d.).

In Nigeria, informal food vending is a major source of food outside the home. Studies of street-vended foods and of vendors’ knowledge, attitudes and practices in Nigerian cities show that food safety remains a concern (Mazi et al., 2023; Iwu et al., 2017; Nordhagen et al., 2022). A recent mixed-methods study of 320 vendors in four major Abuja markets found that only about 64% had food safety knowledge, only 48% observed good hygiene practices, 43% had reliable potable water and 34% wore protective gear; 38% of food samples exceeded aerobic plate count limits, 29% contained Escherichia coli and 33% contained Staphylococcus aureus (Yakubu et al., 2026). The study also found that knowledge was positively correlated with good practice and that hygiene was negatively correlated with microbial load, but it concluded that awareness alone was not enough without water, facilities and enforcement (Yakubu et al., 2026). Studies of food handlers in other Nigerian settings, such as Sokoto, have also examined knowledge and practices related to food hygiene (Ezenwoko et al., 2017).

Universities have a particular responsibility, because large numbers of students and staff depend on food sold on campus. At Ahmadu Bello University (ABU), Zaria, there has been little systematic documentation of the hygiene practices of food vendors or of cases of foodborne disease in recent years. This study therefore examines the knowledge, attitude and practice of food hygiene among food vendors at ABU, Zaria.

Aim and Objectives

The general aim of the research is to determine the type and level of food hygiene practices adopted by food vendors at Ahmadu Bello University, Zaria, Kaduna State, Nigeria. The specific objectives are to:

1. assess the level of knowledge of food hygiene among food vendors at ABU, Zaria;
2. assess the attitude of food vendors towards food hygiene;
3. assess the food hygiene practices that the vendors adopt while running their business;
4. investigate the type of medical examination carried out before a new vendor is engaged and the periodic examinations carried out afterwards; and
5. screen the food vendors for asymptomatic carriers of Salmonella species, which are important pathogens that can cause food poisoning.

Justification

Food hygiene is a serious concern in developing and developed countries alike, because the effects of contaminated food can be devastating. When an outbreak of foodborne illness occurs, people suffer, and the economy, the workforce and the health facilities are all strained (WHO, n.d.).

Research on food vendors points to a gap between what vendors know and what they do. A review of studies of vendors in low- and middle-income countries has examined their knowledge, attitudes and practices on food safety (Wallace et al., 2022), and the knowledge–attitude–practice model, in which attitudes may mediate the effect of knowledge on behaviour, has been used to study food handlers (Kwol et al., 2020). In the Abuja study, even among vendors with knowledge, practice fell short because of lack of potable water and protective gear (Yakubu et al., 2026). Training has been shown to improve the knowledge and behaviour of food service workers (Adesokan et al., 2015). Vendors who handle food are also potential carriers of pathogens such as Salmonella and may infect consumers without showing symptoms, which makes medical screening important; typhoid fever, which is caused by Salmonella Typhi, remains a significant disease in endemic areas (Amicizia et al., 2019).

An institution of the size and standing of Ahmadu Bello University has a large responsibility to keep its students and staff safe from the effects of food poisoning. Because foodborne illness has not been well documented on campus in recent years, a study of the hygiene practices of the university’s food vendors is justified.

Definition of Terms

Cleaning: the removal of soil, food residue, dirt, grease or other objectionable matter from surfaces such as plates, spoons, cutlery and utensils (Codex Alimentarius Commission, 2020).

Contaminant: any biological or chemical agent, foreign matter or other substance not intentionally added to food that may compromise its safety or suitability (Codex Alimentarius Commission, 2020).

Contamination: the introduction or occurrence of a contaminant in food or the food environment (Codex Alimentarius Commission, 2020).

Disinfection: the reduction, by chemical agents or physical methods, of the number of micro-organisms in the environment to a level that does not compromise food safety or suitability (Codex Alimentarius Commission, 2020).

Establishment: any building or area in which food is handled, and the surroundings under the control of the same management (Codex Alimentarius Commission, 2020).

Food hygiene: all conditions and measures necessary to ensure the safety and suitability of food at all stages of the food chain (Codex Alimentarius Commission, 2020).

Hazard: a biological, chemical or physical agent in, or condition of, food with the potential to cause an adverse health effect (Codex Alimentarius Commission, 2020).

HACCP (Hazard Analysis and Critical Control Point): a system that identifies, evaluates and controls hazards that are significant for food safety (Codex Alimentarius Commission, 2020).

Food safety: assurance that food will not cause harm to the consumer when it is prepared or eaten according to its intended use (Codex Alimentarius Commission, 2020).

Food suitability: assurance that food is acceptable for human consumption according to its intended use (Codex Alimentarius Commission, 2020).

Primary production: those steps in the food chain up to and including harvesting, slaughtering, milking and fishing (Codex Alimentarius Commission, 2020).

Food vendor: any person who directly handles packaged or unpackaged food, food equipment and utensils, or food contact surfaces and is therefore expected to comply with food hygiene requirements.

Food premise: any permanent or semi-permanent facility that stores, prepares or handles food.

Food poisoning: an illness of the digestive system that results from eating food or drinking water contaminated by bacteria, bacterial toxins or, less commonly, residues of insecticides or poisonous chemicals such as lead and mercury. It can also be caused by ingesting fungi or berries that irritate the digestive system.

References

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Amicizia, D., Micale, R. T., Pennati, B. M., Zangrillo, F., Iovine, M., Lecini, E., Marchini, F., Lai, P. L., & Panatto, D. (2019). Burden of typhoid fever and cholera: Similarities and differences. Prevention strategies for European travelers to endemic/epidemic areas. Journal of Preventive Medicine and Hygiene, 60(4), E271–E285. https://doi.org/10.15167/2421-4248/jpmh2019.60.4.1333

Codex Alimentarius Commission. (2020). General principles of food hygiene (CXC 1-1969, Rev. 2020). Food and Agriculture Organization of the United Nations and World Health Organization.

Ezenwoko, A., Awosan, K., Oche, M., Makusidi, M., Abubakar, B., & Raji, I. (2017). Knowledge and practices related to food hygiene among food handlers in Sokoto, Nigeria. International Journal of Tropical Disease & Health, 26(1), 1–6.

Iwu, A. C., Uwakwe, K. A., Duru, C. B., Diwe, K. C., Chineke, H. N., Merenu, I. A., Oluoha, U. R., Madubueze, U. C., Ndukwu, E., & Ohale, I. (2017). Knowledge, attitude and practices of food hygiene among food vendors in Owerri, Imo State, Nigeria. Occupational Diseases and Environmental Medicine, 5(1), 11–25. https://doi.org/10.4236/odem.2017.51002

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Mazi, I. M., Onyeaka, H., Akegbe, H., Njoagwuani, E. I., Ochulor, C. E., Oladunjoye, I. O., Omotosho, A. D., Nwaiwu, O., Tamasiga, P., & Odeyemi, O. A. (2023). Street vended foods in Nigeria: An analysis of the current state of affairs and the way forward. Cogent Food & Agriculture, 9(2), Article 2266194. https://doi.org/10.1080/23311932.2023.2266194

Nordhagen, S., Lee, J., Onuigbo-Chatta, N., Okoruwa, A., Monterrosa, E., Lambertini, E., & Pelto, G. H. (2022). What is safe and how much does it matter? Food vendors’ and consumers’ views on food safety in urban Nigeria. Foods, 11(2), 225. https://doi.org/10.3390/foods11020225

Wallace, F., Mittal, N., Lambertini, E., & Nordhagen, S. (2022). Vendor knowledge, attitudes, and practices related to food safety in low- and middle-income countries: A scoping review. Journal of Food Protection, 85(7), 1069–1078.

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World Health Organization. (2006). Five keys to safer food manual. WHO.

Yakubu, I. M., Oladele, O. P., Oluwatuase, T. D., Oniyide, A. C., Olaniyan, K. A., & Olaniyi, O. J. (2026). Food safety knowledge, hygienic practices, environmental conditions, and microbial contamination among food vendors in Abuja, Nigeria: A cross-sectional mixed-methods study. The Nigerian Health Journal, 26(2), 936–944. https://doi.org/10.71637/tnhj.v26i2.1414