Introduction to Food borne hazards and food safety


A healthy diet comprising fresh green vegetables, meat, egg, milk etc provides us essential nutrients and adequate energy for maintaining a good health. Access to healthy and safe food is a basic human necessity. A critical part of healthy eating is keeping foods safe. Food Safety is the assurance that food will not cause harm to the consumer when it is prepared and consumed according to its intended use.  Foodborne and waterborne diarrhoeal diseases kills an estimated 2.2 million people annually, most of whom are children. Maintaining food safety and quality is thus essential in the entire chain of food production. When it comes to improving food safety in India, much has been achieved in recent years following the implementation of Food Safety and Standards act.  In recent years, the organizational structures have been improved, food monitoring and inspection activities have been stepped up, consumer information has been made more transparent and food poisoning cases are being regularly monitored. Protecting the consumer is a dynamic process and an ongoing responsibility which must move with the times.  Food safety must be guaranteed day in, day out.  Working to improve food safety is thus a daily obligation for everyone involved in food production.

Food systems in developing countries are not always as well organized and developed as in the industrialized world. Moreover, problems of growing population, urbanization, inadequate supplies of potable water, sewage disposal, environmental pollution, deliberate adulteration, lack of resources to deal with pre- and post- harvest losses in food, food contamination indicates that food systems in developing countries continue to be stressed, adversely affecting quality and safety of food supplies. Following the recurrence of serious events of food contamination across the globe, food safety has become a matter of ever increasing international concern and the World Health Organization has defined foodborne diseases as a global public health challenge.  Although governments are doing their best to improve the safety of the food supply, the occurrence of foodborne hazards remains a significant threat in both developed and developing countries.

Safe food concept should be sensitized for street food vendors

Street foods are readily accessible and affordable to urban populations, and they provide the energy and nutrient needs of large segments of public in the cities.  Street food has become an important part of diet for many people as such food is easily accessible and affordable. It also plays an important role in providing employment opportunities for millions of men and women with limited education or skills, especially as the initial investment is low. Clean and nutritious street foods have a positive impact on food security. According to the Food and Agriculture Organization, 2.5 million people eat street food daily. Types of vending sites encompass stalls, a variety of push-carts, roadside stands, and hawkers depending upon the ingenuity of the individual, resources available, type of food sold and the availability of other facilities. In spite of numerous advantages offered by street foods, there are also several health hazards associated with this sector of the economy. Vendors usually congregate in overcrowded areas where there are high numbers of potential customers. Such areas usually provide limited access to basic sanitary facilities. Under unhygienic conditions the health risk posed by such foods may outweigh their benefits. The risk is dependent primarily on the type of food, the method of preparation and the manner in which food is held before consumption.  Mishandling and disregard of hygienic measures on the part of the food vendors may enable pathogenic bacteria to come into contact with food and in some cases survive and multiply in sufficient numbers to cause illness in the consumer. Most of the foods are not well protected from flies, which carry food borne pathogens. Safe food storage temperatures are rarely applied to street foods. Potential health risks are associated with contamination of food during preparation, post cooking and other handling stages. Health hazards from street food vending may be minimized by avoiding poor handling and creating awareness of need for personal hygiene and care in preparation, storage and dispensing of street foods.

Types of food hazards

Food hazards are the biggest threat to food safety. A hazard is defined as: a chemical, biological, or physical agent in a food, or condition of a food, with the potential to cause an adverse health effect.

Some of chemical hazards are Pesticides, Adulterants, Additives, colours, flavors, Drug residues and naturally occurring food toxicants. Consumers are most concerned about pesticide usage and adulteration. Common varieties of Pesticides are Insecticides to control insects, Rodenticides to control rodents, Herbicides to control weeds, Fungicides to control mold and fungus and acaricide to control ticks. Pesticides may be found in milk, food crops, tea plantations following spraying to control pest and weed.  The tea plantations in India operate under several statutes and laws passed by the Government of India – notably the Food Safety & Standards Act 2006 (FSSA). Teas complying with these standards are safe to consume.  While the use of pesticides in agriculture has proved to be very essential for the yield and economic success of the crop, it has deep impact on the quality of the soil, water and biodiversity. The intensity of this impact can be seen in some banana farmers where literature reveals the usage of huge quantities of furudan or carbofuran pesticide to meet the increasing demand for enhanced productivity. This trend has resulted in the development of more virulent pests, affected the biodiversity of the region and resulted in a highly polluted environment. Also there is an increase in the number of patients suffering from incurable diseases such as cancer. Licking behavior in cattle and environmental contamination arising from pour-on acaricides for cattle was found to be associated with unexpected residues in meat and dairy products and as an environmental contaminant via cattle dung.

Food supply systems in developing countries are often fragmented involving a multitude of middlemen. This exposes it to various types of fraudulent practices which include adulteration of food with something of lesser value or no value at all with the intent of misleading the consumer. A food adulterant is any material added to food which might be a hazard to our health especially if consumed over a long period of time. The impact of adulteration on economic sector involves economic losses as food rendered unfit for consumption. In addition there involves the cost of treating people who have fallen sick, been disabled or the heavy cost of lives lost.

Chemicals like urea, sodium carbonate, sodium hydroxide, formaldehyde and hydrogen peroxide added to increased shelf life of milk can be harmful when ingested. They can damage the body’s intestinal lining t.  Un- permitted food additives can also cause serious damage of health. The use of certain colours has been banned as they are well known or their toxicity in experimental animals. Non- permitted colours like Rhodamine B, Sudan red, malachite green, Orange II lead to retardation of growth and affects the proper functioning of vital organs and the immune systems. It is a common malpractice to add brick powder to chilly powder, metanil yellow coloured saw dust to turmeric, papaya seeds in pepper, paraffin to coconut oil etc. Foods grown in the open environment, can become contaminated with natural and human-derived environmental toxicants.  Heavy metals are contaminants that may occur as residues in food from the environment / industrial activities or from food processing. Heavy metals are silent killers which slowly accumulate in the vital organs where they degrade health. Common toxic metal contaminants are Lead, Mercury, Arsenic, Cadmium, Copper, Iron, Manganese, Zinc, Tin and Chromium

Physical hazard is any material not naturally found in a food, which may cause illness or injury to the individual using the products. Sometimes glass, wood, stones and metal which may cause illness and injury can also be seen on foods. For example, stapler pin can accidentally be seen in food products during careless packaging, stones may be found in rice. Other examples of inadvertent materials resulting from processing and handling food are  glass, metal, wood, nuts, bolts, cloth, paint chips, rust, etc

Biological hazards are living organisms, including bacteria, viruses, fungi and parasites. It is estimated that almost 70% of the approximate 1.5 billion episodes of diarrhoea that occur in the world annually are directly caused by biological or chemical contamination in foods. Food industry, however, is most concerned about the microbiological safety of its products. Headline news stories focusing on widespread outbreaks of foodborne illness on virtually every Continent are vivid reminders that the food that nourishes and sustains us also can be debilitating,  and in some cases, deadly.

Food today is more extensively processed, is handled at more steps between farm and table, and is stored for longer periods creating opportunities for microbial contamination. Contamination of food can happen at any point during growing, harvesting, processing, storing, shipping or preparing. Poor personal hygiene, improper cleaning of storage and preparation areas and unclean utensils contaminates raw and cooked foods. Expanding urban migration and increased dependence on stored foods coupled with insufficient access to safe water and sanitary food preparation facilities have led to food borne diseases. Improper cooking techniques which includes Inadequate re-heating of potentially hazardous foods, Mishandling of raw and cooked foods allows bacteria to grow.

Food borne illness

When a microorganism is ingested along with a food, it can cause a foodborne infection. After ingestion, the organism burrows into the lining of the victim’s digestive tract and begins to grow in number. This can lead to the common symptoms of foodbrone illness such as diarrhea. Bacteria, virus, and parasites are examples of microorganisms that can cause infection. Intoxication is caused when a living organism multiplies in or on a food and produces a chemical waste or toxin. If the food containing the toxin is ingested the toxin causes an illness. The common examples of food intoxications are Clostridium botulinum and Staphylococcus aureus. Intoxication may also occur when an individual consumes food that contains manmade chemicals such as cleaning agents or pesticides. A toxin-mediated infection is caused when a living organism is consumed with food (as in the case of an infection). Once the organism is inside the human body it produces a toxin that causes the illness. Toxin-mediated infection is different from intoxication because the toxin is produced inside the human body. Food poisoning is a common, usually mild, but sometimes deadly illness. Typical symptoms include nausea, vomiting, abdominal cramping, and diarrhea that occur suddenly after consuming a contaminated food or drink. Depending on the contaminant, fever and chills, bloody stools,dehydration, and nervous system damage may follow

The causative agent must be present in the food. It can originate from the food itself, from handling the food somewhere in the chain of production, from equipment or utensils and from the processing environment. Bacteria responsible for food borne illnesses includes Staphylococcus aureus, Salmonella, Clostridium perfringens, Yersinia enterocolitica, Campylobacter jejuni and Listeria monocytogenes.  Nearly 50% of all foodborne disease cases are associated with temperature abuse (that is inadequate cooling or heating)

In response to such public concerns, government has tightened food safety regulations through an evolution of risk-reducing standards and regulations called as the Food Safety and Standards Act, 2006. The Food Safety and Standards Authority of India is an autonomous statutory Authority for laying down science based standards for articles of food and to regulate their manufacture, storage, distribution, sale and import, to ensure availability of safe and wholesome food for human consumption. The Act aims to establish a single reference point for all matters relating to food safety and standards, by moving from multi-level, multi-departmental control to a single line of command. Ministry of Health & Family Welfare, Government of India is the administrative ministry for the implementation of FSSA Although food safety legislation affects everyone in the country, it is particularly relevant to anyone working in the production, processing, storage, distribution and sale of food, no matter how large or small the business. The standards not only deal with food safety concerns, such as pesticide residue and food additives, but also encompass product quality and social and environmental issues

Control of Food Hazards

1. The best way to combat the food borne problems is to maintain good hygienic conditions around the storage, packing, processing and marketing places. Precautions should be taken in handling the produce so that there is no damage to the containers and contents remain intact & unexposed to the atmosphere.

2. Pesticide control includes observation of recommended withdrawal periods before consumption of milk, meat or food crops sprayed with the chemicals.

3. Laboratory detection of adulterants and pesticide. The laboratories of Kerala Veterinary and Animal Sciences University has the infrastructure to detect the levels of pesticide residues, antimicrobial residues etc in food and water. The Central Instrumentation has Liquid Chromatograph-tandem Mass Spectrometry which is a powerful technique that has very high sensitivity and selectivity to detect the residues in food. The Food Quality Assurance laboratory of KVASU conducts research on food borne pathogens like Salmonella, E. coli, Vibrio, Staphylococcus aureus etc. The lab has got the facility for isolation of organism and molecular research.

4. To control physical hazards during food manufacture, most manufacturers protect by installing metal detectors on the production lines which reject food if anything metallic is present.

5. As part of its global strategy to reduce foodborne diseases through education of the general population, WHO developed a set of simple and clear messages – “Five keys to safer food”. The “Five keys” messages were: (i) keeping clean; (ii) separating raw and cooked food items; (iii) cooking thoroughly; (iv) keeping food at safe temperatures; and (v) using safe water and raw materials.

6. The consumer should buy fresh food from reliable suppliers with clean premises. Always check expiry dates of raw material and processed food and should not buy products in damaged or dented packs.


In global food market now consumer safety is the top most priority. To fulfill this is a hard task because food is very complex commodity and has to face number of biological, chemical and physical hazards. Minimizing these hazards along the food chain requires ongoing effort at different levels. There is currently a lack of coherence among different departments concerning agriculture, food, trade, industry and health. Hence, we need to adopt One Health strategies to achieve food safety. Eating safe, nutritious, healthy food provides everyone with the energy they need to enjoy a healthy and active lifestyle. COHEART has developed series of food safety videos for the purpose of farmers, meat handlers, food business operators, kitchen workers etc.


Dr. Prejit Nambiar, MVSC, Ph. D, is the Assistant Professor of Vet. Public Health & Officer-In- Charge of Centre for One Health Education, Advocacy, Research and Training (COHEART).

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