2. Introduction Consumer health can be defined in terms of what people consume in order to be healthy. Food is what we consume to give us nutrients for growth, sustenance and replacement of worn out tissues.

3.  Food with little or no nutrients, incomplete nutrients when consumed on a regular basis will result into bad health such as growth retardation, sicknesses, loss of body immunity against diseases etc  Food with contaminants are deleterious to human health  Over processed food will lead to loss of protein and vitamin  Regular consumption of food with only carbohydrate leads to a condition called kwashiorkor  Lack of enough supply of energy results in a protruded belle, thin arms and legs or swollen body in a condition called marasmus.

4. Toxicants of Foods A toxicant is any chemical substance that can elicit a detrimental effect in a biological system. Food toxicant can be divided into three categories, namely endogenous, naturally occurring and synthetic. 1. Endogenous Toxicants  substances produced by tissue cells in plants and other biological raw materials.  chemical substances often serve the purpose of protecting plant tissues from pests, as well as from pathogenic organisms

5.  Transmission to man can be direct consumption of toxic plants or from animals who have consumed the plant that are then used for human foods  Examples include flavonoids, goitrogens, coumarins, cyanogenic compounds, herbal extracts, and mushroom toxins.

6. 2. Synthetic toxicants  They are those that are synthetically produced, which found their way into our food supply through contamination of the food processing environment. e.g pesticides, additives, preservatives  Pesticides include insecticides, herbicides, rodenticides, fungicides, fumigants etc.  Amide herbicides (propanil) which is used extensively to control harmful weeds in rice crops could cause liver damage, central nervous system depression and death.

7. A new method of pest management (Integrated Pest Management-IPM) which is based on the minimal use of chemical pesticides to control insects was introduced in the 1980s. IPM seeks to integrate several techniques to control insects and other pests, instead of relying solely on chemicals. The concentration of residues that can be found in foods produced from treated crops is being regulated (maximum residue levels-MRL) in such a manner that strict compliance is demanded.

8. 3. Naturally occurring Toxicants They are those produced by organisms that contaminate the food products. Microorganism such as dinoflagellates, fungi, and bacteria can produce toxicants that upon consumption can cause diseases. Some toxin-producing organisms produce toxins in the food matrix (which can cause intoxication if consumed), while others produce toxins inside the victim (intoxification). some able to withstand heating temperature used in cooking, while others are able to tolerate extremes of pH without losing activity.

9. Some of these Micro organisms cause very serious diseases such as typhoid, dysentery, salmonellosis, cholera and food intoxications. They are generally specific depending upon the type of food and particular conditions of storage. e.g moulds (Aspergillus) are commonly associated with cereal product spoilage, Lactic acid bacteria (Lactobacillus) spoils raw milk and yeasts (Saccharomyces) spoil fruit juice when stored under unfavourable conditions.

10. The undesirable changes caused by microorganisms can be divided into: those that cause food spoilage not usually associated with human disease and those that cause food poisoning which could be: i. food infection, ii. food intoxication or iii. food intoxification.

11. i. Food infections are caused by disease organisms which are carried to the host through foods; they multiply in the intestinal tract, vaginal trud etc and cause diseases through infection of their tissues. Examples of these diseases are cholera, salmonellosis, shigellosis, ameobiosis.

12. Cholera is caused by Vibrio comma, transmitted through drinking water and contaminated food. The symptoms are diarrhoea, watery stools and vomiting. Salmonellosis is caused by salmonella bacteria transmitted through foods such as meat, egg and fish. They are easily killed by normal good cooking, and must be eaten alive in sufficient number to cause infection. Symptoms are abdominal pain, diarrhea, frequent vomiting and occasional death may occur when untreated.

13. ii Food intoxication is caused by organisms which grow in food and produce chemical substances in the food which is toxic. Examples are Staphylococcal poisoning, caused by Staphylococcus aureus. Symptoms are salivation, nausea, vomiting, diarrhea and abdominal cramps. Sources of contamination are mouth, throat, nose through coughs and sneezes. Botulism which could be very fatal is caused by Clostridium botulinum transmitted through home canned foods which are not properly processed. Symptoms are vomiting, constipation, difficult of eye movement, difficulty in speaking. Death could result due to the paralysis of the muscles responsible for respiration.

14. iii Food Intoxification: is caused by ingestion of bacteria that once inside the small intestine, begin to produce toxin. The organism E. coli O157:H7 is a good example of this type of pathogen, able to produce toxin after damaging the lining of the intestine. These toxins are absorbed by the body, reaching the kidneys where they cause substantial damage to the convoluted tubules. In addition to serotype O157:H7, other enterohemorrhagic E. coli serotypes are O145:H-, O26:H11, O104:H21, and O111:NM.

15. The following steps could be taken to avoid consumption of contaminated foods:  1. Avoid overdose use of pesticides or preservatives such as sodium benzoate.  2. Samples of food crops or food product should be tested for residual pesticides or preservatives by appropriate agencies e.g. NAFDAC to ensure safety before they are distributed to the market for consumers.  3. In preparation of foods, simple unit operations such as peeling/dehulling, soaking, dewatering, boiling, roasting and drying could get rid of the natural food toxins and antinutritional constituents to insignificant levels when properly done.  4. Properly cooked food before consumption will prevent food poisoning by microorganisms.  5. Good hygiene, good handling of food to avoid recontamination after cooking and proper storage of food before consumption (Good Manufacturing Practices)

16. Risk Assessment for Biological Hazards Risk assessment refers to the determination of the risk posed by an entity or situation to a population. To carry out risk assessment of biological hazards, there is need to determine the probability of risk. In this method, the probability, or likelihood, of an adverse event occurring due to consumption of a biological hazard is determined. In addition, the magnitude, or severity, of the risk, even if unlikely to happen, is taken into consideration.

17. To carry out a risk assessment of biological hazards, the following steps is carried out:  1. Identify and characterize the hazard (is it bacterial, viral, etc?)  2. Assess the dose required (number of microorganisms) necessary to produce illness.  3. Assess the exposure of the population to the particular biological hazard (prevalence of the organism in a particular food).

18. In conducting a risk assessment, several mathematical models of probability can be used. The most common is the Poisson distribution, expressed as: P = 1 - e¯ RN where P= probability (in percentage) of infection with a food borne pathogens, also known as the risk; R is a constant specific to a particular pathogen, based on its growth characteristics, also known as the probability of getting sick if one cell of the pathogen is consumed; and N is the number of cells of the pathogen present in a particular food.