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Insect pest in food industry in relation to public health concerns


The insects that live, feed, grow, and reproduce on or near the food items are called insect pests. We will not only discuss the insect pest of our food items in our home but also the insect pest of stored food items in stores, restaurants, bakeries, godowns etc. these insects not only just feed on the grains or other food items but also are the source of various disease-causing agents which in result make people sick causing many diseases. The presence of insect pest on the commodity during exportation cause the rejection of the whole shipment for export, in the same way, the commodity with insect pest on it cannot be entertained as an import.


Cockroaches are nocturnal insects, share human food and shelter and are the vectors for the transmission of various disease-causing agents including 33 types of bacteria including Salmonella spp,  Shigella spp, Pseudomonas, Aeruginosa, Parasitic worms of 6 categories, they carry contaminations through their legs from sewage and garbage directly to the food in our kitchen and in the food industry including bakeries, restaurants godowns and storehouses their dropping also cause severe food contaminations cockroaches to belong to insects order Blattodea and it includes 3000+ species out of which 3 are the most common species found on food items as a pest. They are commonly found on the food items placed in your kitchen.

German cockroaches are Light brown to tan colouration, adults are 12-15mm long, and they need Wet humid conditions to survive, found in Food industries, kitchens and bathrooms bacteria they transmit are Enterobacter and Citrobacter.  

American cockroaches are the largest cockroaches that are Reddish-brown and 35-40mm, they need Warm humid conditions and live in Sewers, drains storage rooms they transmit bacteria like Staphylococcus aureus

Oriental cockroaches are dark brown to black, 2-25mm long require Cooler dark and damp places found in Basements, drains storage rooms bacteria they transmit are Salmonella, E.coli

Diseases caused by cockroaches are cholera, typhoid, dysentery and diarrhoea 


Flies are diurnal insects belongs to insects order Diptera, they are of major public health concerns they cause damage in food, healthcare and pharmaceutical sectors to a major extent by feeding and breeding on the food items. They are found commonly hovering on both disposed and fresh food items in your kitchen.

Flies are of many types the most common is the common housefly it plays a role in food contamination as a vector for 100 + disease-causing bacteria like salmonella, Escherichia coli staphylococcus, flies fly over garbage, faeces and sewage and come to the food items with all that contaminations and a lot of disease-causing agents, they also vomit and defecate on food making it contaminated. They are the cause of 65+ diseases for humans including Dysentery, Diarrhea, Cholera, Typhoid etc.  

Flies can also be categorized for convenience into drain flies and fruit flies.

Drain flies are attracted to rotting food, to sewage and waste materials and lay eggs there.

Fruit flies feed on fermenting sugary liquids and also breed there


Moths belong to order Lepidoptera,  do less harm to the food products as compared to cockroaches and flies discussed earlier but they contaminate the food with various products such as eggs, larvae, cocoons and cocoons shells 

Webbing is caused by larval spin as they move on the surface of infested material which is the main cause of contamination causing food particles to stick in the web, pantry moth is the common moth on food items and lay eggs on bread, cereals, flour, rice, nuts, grains etc. they mostly prefer dry food 

Moths transfer various diseases by disease-causing agents, bacteria.  Lepidopterism is a disease caused by the toxic fluid of adult moths.

Stored product pest

Stored pests are those which feed live and breed on the stored dried food products in homes restaurants grocery stores and go downs etc. in a result they contaminate them and also cause foul smell causing irritation and allergy to us ultimately the loss of stored product 

Weevils, beetles and moths are the common insect pest of stored products 


Beetles belong to the order Coleoptera, they not only feed on the stored product but also dispose of feces, eggs, grubs and body part, both larva and adult feed on rice and wheat grains.

 Beetles are called secondary pests, lays eggs on the grains and cause a pungent smell causing allergies and irritations to human health.

Beetles causing damage to the stored products include 

Saw-toothed grain beetle, dark red or brown, 1/10 inch long insect

Confused and red flour beetle, are reddish-brown, 1/7 inches long insects

Anobiid beetle includes cigarette beetle and drugstore beetle


Weevils are from order Coleoptera, they are primary insects, they cause the major infestation to commercial food processing or food handling business, and they can ruin entire food shipment, they cause more damage than eating,  damage caused by them is 30% due to eating and 70% due to the contamination by their feaces, body parts, eggs, foul smell etc. They lay eggs in the grains.

Weevils include 

Seed weevil damaging beans and peas, they have a stout body,3/16 inches long, are dull grey to brown. The most common species are cowpea weevil and bean weevil.

Grain weevils, 3/16 inches brown to black insects, eat fresh grains and larva make holes in the seeds. The most common species of grain weevils are rice weevil, maize weevil, lesser grain borer etc.


Moths are from order Coleoptera, the damage is caused by the caterpillar mostly.

Moths are categorized into two groups, flour moths and grain moths.

Flour moths attack on processed grains and flour, the most common species are the Indian meal moth and Mediterranean flour moth.

Grain moths are those which feed, live and breed on fresh unbroken kernels and grain, common species is the Angoumois grain moth.

Stored product pest effecting human health

Insects pest of the stored product also carries disease-causing agents like bacteria and viruses causing various diseases in humans by contaminating the food like grains and cereals. Anaplasmosis, Zika virus, Lyme virus, West Nile virus, Chikungunya, Ehrlichiosis etc. These diseases will be transferred to people after feeding on such contaminated grains.

Secondary pest includes beetle and they produce foul smell in the cereals and grains they reside and feed on which is very irritating and allergic to many people causing severe coughing, sneezing and allergic reactions.


The insect pest of food is of great importance, they can cause the loss of stored commodity up to 60% depends upon the rate of infestation. Unhygienic conditions ultimately the favourable conditions for them should be avoided and the proper inspection is needed for their control. Non-chemical control is preferred so the commodity should not be got contact with the chemicals to make any toxicity.

Aena Rauf 
BSc. Agriculture Entomology, 
Department of Entomology, University of the Punjab, Lahore


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