Pest Control for Food Safety - III

Stored Product Insects

This group includes large number of insects which attack foodstuffs of raw materials in storage, transport and manufacture. The group includes beetles, weevils, moths and their larvae which attack dried products, cereals, flour, beans, and nuts. It has been estimated that approximately ¼ to 1/3 of the world grain production is lost in the storage mostly due to pest attacks each year.  In addition, grain which is not lost is severely reduced in quality by insect damage and many grain pests preferentially eat out grain embryos, thereby reducing the protein content of feed grain and lowering the percentage of seeds which germinate. Stored food product pests are found in almost every home at some time or most of the food storage. Yet few people recognize why stored product pests occur, or how to identify them. Many are transported into the home from a store or warehouse, since most of the storage act as their buffer stocks. In last article we discuss the beetles ad here rest of the most common storage food pest are given here. But this is not a comprehensive list since there many different storage pests in different parts of the world and we only try to discuss most common types here.

Granary Weevil – Sitophilus granarius

The Granary Weevil is among the most destructive of all stored grain insects, because of their larvae develop inside kernels of whole grain in storage, which makes an infestation difficult to remove in the milling process. Most of their life is spent within the grain kernel and both larvae and adults feed on grain where they also attack hard cereal products such as macaroni and spaghetti.

The adult insect is about 2.5 - 5 mm in length and dark brown-black in colour, which possess a long slender snout and cannot fly. Females drill a tiny hole in the grain kernel and deposit an egg in the cavity, then plug the hole with a gelatinous secretion. The egg, larva, and pupa stages of these weevils occur in the grain kernels and are rarely seen, where larval stage of the weevils are legless, humpbacked, with white to creamy white colour, with a small, tan head. Weevils in the pupa stage have snouts like in the adults. Emergence holes of the granary weevil are fairly large and tend to be more ragged than smooth and round. The life cycle is about 30 to 40 days during the summer, and 123 to 148 days during the winter, depending on temperature.

Maize Weevil - Sitophilus zaemais

Also known as the Greater Rice Weevil which are frequently regarded as primary pests of grain since they are able to infest otherwise undamaged grain as well as they are observed to be infesting buckwheat, peas, acorns, chestnuts and cottonseed. The weevil damaged grain can be readily recognized by the presence of large holes which are the exit holes of the emerging adults, where both larvae and adults will feed upon grain.

Adult insect is about 2.5 - 4 mm long and the head has a long slender snout, which resembles to rice weevil, as differences only bigger and the red-brown spots on wing covers are more clearly marked and it is a stronger flier than the rice weevil. Females drill a tiny hole in the grain kernel, deposit an egg in the cavity, then plug the hole with a gelatinous secretion. The egg, larva, and pupa stages of these weevils occur in the grain kernels and are rarely seen, hence egg hatches into a young larva which bores toward the center of the kernel, feeds, grows, and pupates there. New adults bore emergence holes from the inside, then leave to mate and begin a new generation.

Rice Weevil – Sitophilus oryzae

Rice weevils are pests of stored grain and seeds, where the adults can feign death by drawing up their legs close to the body, falling, and remaining silent when disturbed. Emergence holes of the rice weevil are smaller than those of the granary weevil, and tend to be smooth and round and there is no external evidence that the larvae have been eating and growing inside the seed until after about one month when the adult weevil chews through the seed coat and emerges.

The adult rice weevil is about 2.5 to 3.5 mm in length and has a slender, hard-shelled bodies that appear pitted or scarred with tiny holes and are brown-black in color while possessing a long slender snout as well as they have four faint red-brown spots on the back of the abdomen. Females drill a tiny hole in the grain kernel, deposit an egg in the cavity, then plug the hole with a gelatinous secretion and the egg hatches into a young larva which bores toward the center of the kernel, feeds, grows, and pupates there. Female rice weevils lay between 300 to 400 eggs, with the life cycle requiring about 32 days for completion. Two larvae can develop in one wheat kernel and the egg, larva, and pupa stages of these weevils occur in the grain kernels and are rarely seen. New adults bore emergence holes from the inside, then leave to mate and begin a new generation. The adults live 3 to 6 months, infesting grain in the field.

Bean Weevil – Acanthoscelides obtectus

The adult is 2.0 – 3.0mm long, which is mottled brown in colour and weevil has a ‘tear drop’ like body shape that covered in short hairs. The insect has saw-tooth like antennae and elytra which do not cover the entire abdomen. Life cycle usually lasts 2-4 months and weevils attack all legumes, including kidney beans, green beans, peas and lentils where heavily infested peas are often reduced to shells. Development and breeding goes on as long as there is any food left in the bean and if warmer temperatures are possible within the habitat. The larvae feed within the beans as they mature. The larval stage can take from a few weeks to many months to complete, depending upon temperature and moisture of the bean. Pupation is within the bean and circular holes are cut for the adult to emerge. Larvae feed mostly inside beans.

Coffee Bean Weevil - Araecerus fasciculatus

Adults are 1.5-4mm in length and dark brown coloured with light brown spots and long antennae. They mainly infest corn, cocoa, coffee beans, dried fruits, nutmegs, ginger etc., which flies to fields and lays its eggs on damaged cobs. The footless, slim larvae are curved and hairy and grow to a length of 5-6mm and bore into coffee beans in which they pupate.

Almond Moth – Cadra cautella

The almond moth is found globally in processing facilities, warehouses and households and its nicknames are “Cocoa Moth” and “Tropical Warehouse Moth”, which feeds on grain, cereal products, oilseeds and dried plant products, like nuts, fruit and tobacco. The adult is 7.5 – 10 mm long and wing span is 19 mm. The forewings are grey to dusty brown and dark straight band across the forewing, which is paler on the inner edge. The female lays about 150 - 200 eggs loosely and randomly on a food sources and larva can grow up to 12.7 mm in length and it is white to pink in colour and has a distinctive brown head. The larva burrows into food and creates silk tunnels in which it will be concealed while feeding and large larva can burrow through packing. When the larva is mature, it will actively leave the food source and search for a site to pupate and which is a silk cocoon. The almond moth infests stored products and the adults can fly. The infestation and contamination can be observed with silk webbing, frass, cast skins, pupal cases and adult remains.

Indian Meal Moth – Plodia interpunctella

The adult Indian meal moth causes no damage whereas Indian meal moth’s larvae are a very common commercial and pantry pest. Their larvae produce the web material commonly found in food, such as dried fruits, whole wheat and cornmeal, and shelled or ear corn which attracted to grain or grain products such as corn, many different dried foods including fruit, nuts, seeds, also, biscuits and powdered milk; chocolate, candy; dried red peppers; dry dog food.

Adult has wingspread of about 14 – 20mm which are pale gray wings, but the front wing is reddish brown and coppery on the outer two-thirds. The female lays approximately 200 eggs, on food material during a 1-18 day period of time. The mature larva is usually dirty white, but may vary to greenish, pinkish, or brownish, depending on the food it eats and head region is yellowish to reddish brown. The temperature and availability of food determine the length of the larval stages and the last instar larva leaves the food to find a suitable place for pupation. The complete life cycle occurs within 25-135 days, with 4-6 generations per year.

Mediterranean Flour Moth – Ephestia kuhniella

The Mediterranean flour moth larva is a very common commercial and pantry pest. It is a pest of mills and warehouses as it can clog machinery with its webs. The adult has wingspread of about 20 to 22mm and when at rest it is 10 - 14 mm long. The hind wings are dirty white in colour and the forewings are blue-grey with transverse dark wavy bars and a row of dark spots at the tip. The moth is mostly found infesting flour and meal which also been found infesting grain, bran, cereal products, nuts, chocolate, seeds, beans, biscuits, dried fruits and other stored foods.

The female lays between 100 - 700 eggs (usually 200) in and among the food source and usually fastens the eggs to the infested material. The eggs usually hatch in 3 - 5 days and the hatching larvae produce a lot of webbing and the young larvae confine themselves to silken tubes which are constantly spun. The larvae are white in color with a brown head and neck shield they can take on a pinkish or greenish hue and can reach a length of 15 - 20 mm. The larva reaches complete growth around 40 days. The larva pupates in or on top of the infested material (usually flour) or in cracks and crevices nearby which form a brown, spindle shaped cocoon approximately 9 mm. The life cycle can be completed in as few as 4 to 6 weeks but usually takes about 3 months.

Tobacco Moth – Ephestia elutella

The tobacco moth is an introduced pest species of moths which is often found in warehouses and other areas where food or tobacco is stored, which feeds on cocoa beans and tobacco, but also infests nuts, dried fruit and cereals, but adult moths do not feed. The larval feeding cause the most damage due to contamination with excrement and cocoons, where they infest not only tobacco, but cocoa, nuts, dried fruits, coffee, corn maize, wheat and spice.

The moth has a wing expanse of 14 to 17mm and when the wings at rest they folded to a roof over the body which is 8 to 11mm long. The adult moth has brownish grey forewings crossed with two light bands and the hind-wings are paler and plain grey.The female deposits about 100 eggs, singly or in small clusters which generates caterpillars that are whitish, yellowish or reddish depending on nutrition with brown head and neck shields. The caterpillars grow to a length of 10-15 mm and they cover the infested goods with webbing and their pupation occurs in a cocoon. The development period depends on the temperature and nutrition which further depend on the season, thus lifecycle is completed by 2 to 6 months.

Grain Borer – Prostephanus truncatus

Adult beetle is a pest of stored maize, but also infests other types of grain and the larva bores tubular passages into the grain, typically making one main tunnel with smaller ones branching off. The insect were originated in tropical Central America and transcended in cassava roots and tapioca products, as well as in starchy fruits and tubers. The adult is 1.5 - 4.76mm in length and brown in body colour. The antennae have 3 large segments at the end forming visible antenna clubs, which are reddish in colour. Their humped thorax covers the head, its front rim has teeth–like indentations. Elytra (wing covers) are heavily punctated and drop off sharply at the back, giving the impression of a square end when seen from above.

The female lays an average of 10 eggs on a grain of maize and the hatched larvae bore into the grain and the larva undergoes up to 4 development phases and pupates inside the corn grain. The lifecycles can be quite short, in optimum weather conditions their lifecycle can completed i.e. 25 days at 34 °C, 75% relative humidity and they can produce several generations per year.

Lesser Mealworm – Alphitobius diaperinus

The beetles are attracted to poultry operations, which have ideal conditions for their development. Nonetheless, they damage to insulations, covered places in search of seeking a safe place to pupate because the darkling beetles prey on the lesser mealworms. The adult insects are 6mm long and the newly moulted adults are reddish-brown turning black. Females can lay up to at least 110 eggs a month and eggs hatch in 4-7 days, whereas larval development takes up to 7 weeks. The larvae are 8mm long, slender, segmented and worm-like with three pairs of tiny legs on the thorax and one abdominal pro-leg at the rear. Mature larvae seek a sheltered place to pupate for between 7 and 11 days and an adult beetle may live up to two years.

Flour Mite/Grain Mite – Acarus siro 

Adult mites are about 0.5 mm in length and they have 4 pairs of legs and white or pale brown coloured body with slow moving abilities.  Under adverse conditions, it can survive through dormant stage which may pass through a long and very resistant stage called a hypopus. The larvae are 6 legged and 0.5 mm long with white coloured body which need to go through two, 8 legged nymphal stages before become an adult. The lifecycle can be completed in 9 to 11 days at 23°C and 90% relative humidity.

Cheese Mites – Tyrophagus putrescentiae

Cheese mites have soft, hairy cream white bodies with 8 hairless legs and adults grow up to an approximate size of 0.5mm in length. They are preferring for old cheese as well as young cheese, these mites also feed on nuts, dried eggs, fruit, flour and tobacco. The cheese mite favours warm, moist conditions. Females can lay up to 900 eggs in a lifetime at a rate of 20 to 30 a day and eggs mature in 10 days at room temperatures. Adult cheese mites can live around 60 to 70 days, where cheese mites are capable of contaminating foods to cause skin or gut irritation.

Ants

There are various type of ants who infest foodstuff or raw materials. The most common ants are in black or yellow/pale brown colour in nature with approximately around 2mm in length. They love warm weather conditions and usually occur in heated buildings, kitchens, hotels, residential properties, hospitals, etc. where they can often found in seemingly impenetrable food containers. All kinds of food may be attacked, although they prefer sweet, oily or high protein foods. The physical transfer of pathogens are a high possibility since they walk though drains, excreta, and soiled dressings where food is contaminated through their legs and bodies as well as excreta. Nests are difficult to detect and destroy.   

Birds

Birds which considered as food pests are usually pigeons, sparrows, seagulls, crows and other occasional birds. However, sparrows, starlings and pigeons are the most common while gulls are becoming a problem although they rarely enter the buildings. They usually lives in large warehouses, food factories, super markets and other locations or even in the residential buildings. The pathogens associated with birds include salmonella and campylobacter. The prevention is critical since the foods or raw material and equipment can be contaminated through droppings, feathers, bodies and nesting materials, which may transmit food poisoning organisms. They also damage the food packaging to fetch foods or raw materials. They also induce insect or mite infestations due their droppings, feathers, dead bodies and nesting materials which may also block the gutters, and drains resulting flooding and costly maintenance. The bird infestations may also induce defacement of buildings and roosting on fire escapes or similar structures which may create safety hazards for human occupants.        

 

Cats and Dogs

They are also considered as pests, because they are hosts for pathogens such as salmonella and campylobacter in their intestine, mouths or coat and paws, where contamination can occur through feces or urine.     

Pest Control for Food Safety - II

Storage Food Pests

Stored food pests are a large group of insects which are economically important and are responsible for millions of dollars’ worth material loss every year in stored foods and other products. There are many species of stored food pests found at storages, warehouses or food pantries and most of these pests are introduced into our homes in infested food. Most of the stored food pests can reproduce quickly and have several to many generations in a year depending on the environmental conditions whereas many species are active year-round under suitable conditions. Stored foods are commonly infested include flour, cereals, cracked grains, baking mixes and processed foods, crackers, macaroni, cured meats, powdered milk, dried fruits, nuts, popcorn and spices.

Insects that feed on these products may also infest other grain-based items such as pet foods, birdseed and ornamental corn. Dried flower arrangements may also be attacked. Several stages (egg, larva, pupa and adult) of these insects may be present at the same time in infested products. Because warehouses, no frozen storages, barns, cereal storages and houses are usually kept warm, these insects may continually reproduce and many stored product infestations can be found nearly any time of the year. The many different kinds of insects that infest stored dried foods are often beetles, weevils and moths, but there are other insects of different types such as mites, borers, etc. These pests contaminate more food than they eat, and most people find the contaminated products unfit for consumption. Thus, let’s look at some of the major beetles since the group is very large with various different beetles which are infesting different types of stored food items.   

Khapra Beetle – Trogodermagranarium

The Khapra Beetle is considered to be the world's most destructive pest of stored grain and grain products. If left uncontrolled, this beetle can cover the surface of stored grain making it appear alive with crawling larvae. The male is about 2 mm in length and the female is slightly larger (up to 3 mm) and it is a dark-brown beetle with yellow-brown to red-brown markings on the wing covers. Their body is covered with fine hairs which may trap dust, giving them a dirty appearance. The insect is considered as a dirty feeder since it breaks or powders more grain than it consumes while contaminating the grain with larval skins and setae which have been known to cause gastrointestinal irritation. Khapra larvae feed on rice, peanuts, dried animal skins, as well as its preferred natural foods such as wheat and malted barley.

The adults are short-lived insects who complete their adult life in one to two weeks, where mating occurs almost immediately after adult emergence, with oviposition for one to six days following. The female lays up to 125 eggs loosely in the infested material. Eggs hatch in five to seven days and the larvae are yellow to golden brown which is grown up to 5 mm, while they are covered by thick, red-brown hairs with two tufts at the end of the abdomen. The larvae undergo 4 - 7 molts, resulting in the shedding of numerous cast skins. In ideal conditions the life cycle can be completed in as few as 30 days.

Lesser Grain Beetle – Rhyzoperthadominica

The adult beetle is 2.5 to 3 mm in length and black-brown in colour, where their body has a slender cylindrical form and the head is hidden under the round neck-shield. The beetle lives and feeds in warehouses and stores, and it is primarily a pest in stored wheat and corn, but it can infest tobacco, nuts, beans, bird seed, biscuits, cassava, cocoa beans, dried fruit, peanuts, spices, rodenticide baits, and dried meat and fish.

Adult females lay eggs singly or in groups of up to 30, whereas eggs are laid on the outside of the grain and a female can lay from 300 - 500 eggs. The larvae are whitish with a yellow head and pupation takes place inside the hollow shell of the seed or in the "flour" that accumulates with infested grain. In hot summer conditions it may take as few as 30 days, but the average is about 58 days.

Merchant Grain Beetle – Oryzaephilusmercator

The Merchant Grain Beetle is a store pest species found feeding in nuts, seeds, biscuits, dried fruit, grain and various other food products, where it can chew through sealed packaging such as cardboard boxes, plastic bags and foil wrappings. They also found in pantries or in food processing areas or warehouses. The adult beetle is approximately 2.5mm to 3mm in length and dark brown in colour with a slender, flattened body, which can fly (although it rarely does).

The females lays about 300 eggs in her lifetime, which are dropped loosely among grain kernels or tucked into a crevice in a kernel. The tiny eggs are slender and white, and hatch in three to five days when environmental conditions are optimal. Thus, larvae emerge and crawl freely about the grain to feed on broken kernels and larger larvae may tunnel into kernels to feed. The development from egg to adult requires about three to four weeks.

Rust-red Flour Beetle – Triboliumcasteneum

Rust-red flour beetle is a very common commercial stored products pest infesting a variety of grain and food materials. They have been reported in grain, flour, and other cereal products, beans, cacao, cottonseed, shelled nuts, dried fruit, dried vegetables, drugs, spices, chocolate, dried milk and animal hides. However, they can’t feed on whole grain, but can feed on broken kernels that are usually present and in general, fungi may play a significant role in the nutrition of rust-red flour beetles. When agitated or crowded, they may secrete chemicals called quinones, which can cause the infested feed to turn pink and have a pungent odor.

The adult is about 3.0 to 4.5mm in length and it is red-brown in color. The antenna of the rust-red flour beetle is distinctly club-like, with a three segmented club and it has grooved wing covers, which has well developed wings and has been observed to fly. The female lays approximately 400 - 500 eggs, with peak oviposition occurring during the first week, which are deposited directly in flour, other food material, or attached to the surface of the container. Eggs are white or colorless and covered by a sticky material to which flour can adhere. Which hatch in 3 - 5 days at 32 - 35°C. The larvae burrow into kernels of grain but may leave their burrows in search of a more favorable food and they are fairly active but generally hide within the food, away from light. The larvae are a light honey color and about 6 mm long with a head and a distinctive forked process at the tip of the abdomen are slightly darkened. Development time from egg to adult varies with conditions, however as an average, it takes about 26 days at 32 - 35°C and >70% relative humidity (R/H). The adults may live longer than 3 years, and females may lay eggs for more than a year.

Saw Toothed Grain Beetle – Oryzaephilussurinamensis

The saw-toothed grain beetle is one of the most common insects in stored grain and cereal products which is a common pest not only in grain bins, but also, mills, processing plants, warehouses, and kitchens. It feeds on broken kernels and grain residues and beetles can chew through sealed packaging such as cardboard boxes, plastic bags and foil wrappings. The larvae develop in flour, cereal products, and many other dried foods, including grains, cereals, bread, pasta products, dried meat, dried fruit and nuts, sugar, chocolate, candy, tobacco products and drugs.

The insect is approximately 3 mm in length and brown in colour with a flattened body and wings are present and developed, but they cannot fly. The female lays eggs singly or in small batches in the food product which lays about 200 eggs in her lifetime. Eggs hatch after about 8 days and the mature larva is yellowish white. The life cycle takes about 35 days and the larvae feed in the top few centimeters of the food stuff and adults usually live around 6 to 10 months.

Warehouse Beetle – Trogodermavariabile

May be found in many organic materials such as seeds, grains, most types of packaged foods, snail baits, dog biscuits, stock feeds, old rodent baits, grain remnants in sacks, bee and wasp nests, rodent carcasses, dead insects, animal droppings etc. The hairs dropped by larvae may cause human problems such as asthma, skin problems or gastric disorders.

Adult insect is about 1.5 to 4.0mm in length and oval in shape with mostly dark brown in colour, with mottled lighter brown markings. The larva is up to 10mm long, and pale cream with indistinct dark brown markings and it has 3 pairs of legs and is very bristly. Lifecycle usually lasts between 1.5 to 6 months depending on environmental conditions.

Drug Store Beetle/ Biscuit Beetle – Stegobiumpaniceum

The drugstore beetle (also known as the Biscuit Beetle) gained its name because initially it was frequently found feeding on drugs in pharmacies many years ago whereas now they are customarily found infesting all types of dry stored food products, spices, seeds, grains and dried plant material as well as packaging materials such as paper and cardboard. Nonetheless, they are also known to be feeding on leather, wool, hair and books. Adult will often fly and it is 1.5 - 3mm in length and red-brown, oval beetles with humped thorax and entire body covers with fine hairs while elytra (wing cases) have ridges with indentations. 

The adult beetles live from 2 to 4 weeks and during this time the females may deposit between 20-100 eggs. The larvae are small and white approximately 0.5 mm long. The larval period usually ranges from four to five months, but under favorable conditions whereas the development from egg to adult may occur in 6 to 8 weeks. Once the larvae are fully grown, pupation occurs and they remain in this resting stage for 12 to 18 days. Larvae is active in early stages of development which can bore into hard substances.

Broadhorned Flour Beetle – Gnatoceruscornutus

The adult is approximately around 3.5 – 4.5mm in length, male broadhorned beetles have two enlarged mandibles on the head, giving the appearance of horns and thus their name. Females are very similar in appearance to the confused flour beetle. Feeds on flour, dough, semolina etc. and it requires temperature around 15 - 32°C, for growth, where broadhorned flour beetles cannot complete their life cycle below 10°C. Moth eggs and larvae may supplement the broadhorned flour beetle diet.

Cigarette Beetle – Lasiodermaserricorne

The Cigarette beetle is a very common commercial pest and it is about 2-4mm in length, which is whitish in color, with a head dark brown to tan, and are densely haired. The beetle is closely resembles the drugstore beetle which has the head bent down nearly at right angles to the body giving it a humped back appearance when viewed from the side. The Cigarette Beetle feeds off tobacco, dry stored food products, spices, seeds, grains and dried plant material, which also been reported in rice, dried potatoes, paprika, raisins, grain-based mouse bait and dried straw flowers. Adult beetles often wander away from infested materials and may be found throughout the area.

 

The adult beetles live from 2 to 4 weeks and during this time the females may deposit between 10-100 eggs, which are laid loosely on the infested material. The larval period usually ranges from four to five months, but under very favorable conditions the development from egg to adult may occur within 6 to 8 weeks. The larvae are about 4 mm long and somewhat bent. When the larvae are fully grown, pupation occurs and itremains in this resting stage for 12 to 18 days.

Confused Flour Beetle – Triboliumconfusum

The confused flour beetle was named because of the confusion over its identity. It is a very common commercial and pantry pest. The adult is about 3-4 mm in length, which is reddish brown in color and it resembles the rust-red flour beetle, except for the antennae which is four segmented and gradually thickens towards the tip - another slight difference is in the shape of the thorax. The sides of the rust-red flour beetle are curved, whereas the thorax of the confused flour beetle is straighter, which has well developed wings but seldom flies. Insect feeds off grain, flour, and other cereal products, beans, cacao, cottonseed, shelled nuts, dried fruit, dried vegetables, drugs, spices, chocolate, dried milk and animal hides. They cannot feed on whole grain, but can feed on broken kernels that are usually present.

Adults may live longer than 3 years, and females may lay eggs for more than a year which amounts to 400 - 500 eggs, with peak ovi-position occurring during the first week. Eggs are deposited directly in flour, other food material, or attached to the surface of the container. They are white or colorless and covered by a sticky material to which flour can adhere. Eggs hatch in 3 - 5 days at 32 - 35°C. Larvae burrow into kernels of grain but may leave their burrows in search of a more favorable food and larvae is light honey coloured and about 6 mm long.

Copra Beetle/Red Legged Ham Beetle – Necrobiarufipes

The adults is 4.5 mm in length and upper surfaces of the body are a shiny metallic bluish-green with underside of the abdomen is dark blue. Their legs are bright reddish-brown or orange while antennae are reddish–brown with a dark brown or black club at the tip. The adults can fly and therefore easily disperse to new sources of food and are also cannibalistic, preying on their own eggs and pupae. They are destructive in both the larval and adult stages, although the larval stage is the most destructive. Females lay up to 30 eggs per day in cracks or crevices of cured fish, where eggs take between four and six days to hatch. The larvae will grow for 30 to 140 days, become less active and look for a dark place to pupate and the pupal stage varies between 6 and 21 days. An adult will mate soon after emerging from its pupal stage and can live for up to 14 months

Australian Spider Beetle – Ptinustectus

Australian spider beetles are covered in brown and golden hairs, which has a spider-life appearance and adults grow up to an approximate 2.4 – 4mm in length, while it live for up to 3 – 4 months at 20 - 25°C. Larvae are often found feeding on miscellaneous debris, which possesses the ability to bore into various inedible materials prior to pupation. It is active in dark, damp places, which is often associated with bird nests.

Flat Grain Beetle – Cryptolestesferrugineus

Adult about 3mm in length and have a flattened body with very long antennae. Light red to dark reddish brown, which prefers warm damp conditions and life cycle lasts around 69–103 days at 21°C, 26 days at 38°C. Adults having wings but rarely fly and they feeds on cereals, dates, dried fruits and other commodities. Larva is yellowish–white in colour and 0.5mm long growing to 4mm when mature.

Rove Beetle – Paederusriparius

Adult beetle is about 8 to 9.5mm in length and body colour is an alternating black and red, which are common in decaying fruit or seaweed, compost with large numbers of flying larvae. The larvae and adults are general predators of small insects and other arthropods, including pests of crops, which are most common in spring and early summer. Female lay eggs singly on moist substances and typically develop in 3–19 days and the larvae pass through two stages before reaching adulthood. 

Yellow Mealworm Beetle – Tenebriomolitor

Cold weather insect and they are highly resistant to cold temperatures, which is an important post–harvest pest and occurs spread all over the world. Adult beetles are attracted to night-lights, are strong fliers, and are found in dark places, which is 19mm in length and are shiny, dark–brown or black. 

Each female lays about 275–600 eggs singly or in clusters during the spring, which are white, bean-shaped and about 0.75mm long and hatch into larvae in 4 to 14 days. The larvae are honey–yellow in colour and they have a smooth, highly polished, shiny, elongate, hard, worm-like body, which can grow up to 30mm long. The pupal stage lasts 7 to 24 days during the spring, which are first white in colour, turning yellow, and are not enclosed in a cocoon. Adults emerge in the spring or early summer, living for two to three months.

Dermestes Beetle – Dermesteslardarius

Adult – 6 - 9.5mm in length. And coloured in black with a whitish band across the fore–part of the elytra with a life span of 2–3 months at 18–25°C while feeding on various dried foods and animal products including cheese, leather or any dry matter. Their larvae are comet shape which can quickly move and are brown in colour and hairy which migrate to pupate in solid material.

Pest Control for Food Safety

Food Pests

The food pests are the creatures who are destructive, noxious or troublesome and lives on or in the prepared foods or raw materials intended for production of foods or feed for human or animal consumption, which is capable of directly or indirectly contaminate the foods or raw materials. Thus, pest control is an essential part of food safety to prevent the spread of disease, formation of toxic compounds and loss of material including following:

Prevention of contamination through rodents or birds which may result in food poisoning. Rodents are scavengers who use to feed on refuse, waste and or contaminated foods, whereas rats often lives in sewers as well as they are in close association of other animals. Thus, often carry food poisoning bacteria, such as salmonellae, E. coli, etc. both inside and outside their bodies as well as on their feet or mouths. Once they enter to a food processing or holding premise, they can easily transfer the food poisoning organisms to foods or food contact surfaces from their fur, mouths, feet, urine and feces. Thus, rat urine contamination can sometimes lead to Weil’s disease.

Pest control is mandatory, since prevention of wastage due to food contamination as well as losses through the damage of packaging by the pests, which are associated with additional costs due to loss of production, recall of contaminated foods or criminal or civil action as a result of sale of contaminated food stuffs.

It is also important to control pest attacks, because pest damage can cause gnawing electrical fires, burst of plumbing or subsidence, or cause of borrowing may result due to rodent infestations.

Nonetheless, it is important to comply with legislation to avoid possible fines or closure of business as well as to avoid loss of customers who object to pest infested premises as well as sale of contaminated food stuffs. Further, employees will demotivated and abandon the employments due to fear, disease outbreaks or intolerability. 

Common Food Pests

There are various kind of food pests found the industry, however following are the most common in nature.

Rodents – rats and mice

Rodents comprise a group of furred, warm blooded animals which include rats and mice. The two most common rodent encounters are rats and house mice.Rats and mice are attracted by food supplies but do not venture far from their shelter or nesting sites, and will nest close to food sources. They are capable of a rapid increase in population given an abundant food supply, shelter from predators and benign environmental conditions inside a building.

Rats

There are two types of rats and most common are depend on the region, but brown rat (Norway rat/ground rat) and black rats (roof rat) are usually common in different parts of the world, the brown and black rats are the most predominant varieties who usually borrows in the soil, especially beneath the buildings, or usually found in sewers, drainage lines, farms, and rubbish dump yards. They are usually omnivores in nature, but prefer cereals. Usually one pair of adult rats can produce over hundreds of offspring within a year. But their survival is usually less and need to eliminate them as much as possible since lone invaders become pairs soon which will create major infestations with very short time. The contamination along access routes or foods with urine, droppings, and filth picked up from the environment; damage to food containers and packaging; eating food in storage and on display; transmission of diseases, including Salmonellosis, Leptospirosis, Toxoplasmosis, Lyme disease, rat-bite fever; rodents carry ectoparasites, including ticks, fleas, lice and mites and are therefore also vectors for the diseases that these carry; rodents are reservoirs for some mosquito-borne diseases.

House Mice

The house mice are normally found inside the buildings which provide harbourage with warmth, food and secured nesting places and material. It is an omnivorous animal where a single pair can produce around 2000 baby mice within a year through horizontal multiplication of their offspring. 

Insects

Insect are the most troublesome group which contains many different groups including flies, wasps, cockroaches, psocids, silverfish, ants, moths, weevils and beetles. Nonetheless, there are another group called stored product insects, who infest serials, flour and biscuits or any made dry foods/raw materials which are under storage conditions. Insects attack food or raw materials which become contaminated with their excreta, webbings, and eggs or their bodies. Furthermore, flies and cockroaches may act as hosts to transmit food poisoning organisms to high risk or made foods. Thus, no food is completely safe from insect attacks, but cereals, beans, flour and dried foods are among the most susceptible to infestation.

Flies

There are many types of flies, which can cause problems in the food industry including the Housefly, the Bushfly, Blowfly and the Fruit Fly. Filth flies, including house flies, drain flies and flesh flies are known to be able to carry over 100 pathogens that can cause disease in humans, where many pathogens have been isolated from flies, including salmonella, E. coli O157, cholera, shigella, campylobacter, listeria and rotavirus, etc. They also carry parasitic warms and fungi. Thus, flies can contaminate foods or raw materials in four ways; they vomit partly digested pervious meal before feeding starts; and flies continually defecate; they also carry bacteria on their body, legs or hairs; while their pupal cases, eggs, maggots and dead bodies can end up in the foods.

Adult flies lay eggs in moist organic material, for example, food scraps, animal faeces (droppings), grass clippings or dead animals. Theeggs turn into larvae after some hours which are called maggots, who feed on the organic material and grow quickly. After four to five days the maggots move to dry soil and burrow down into it and turn into pupae. A special hard protective covering called a pupal case encloses each of the pupae while they continue to develop. Pupae are brown to black in colour and can sometimes be mistaken for mice droppings.After four or five days, pupae turn into adult flies. They break out of the pupal case, burrow up through the soil to the surface and fly away. Flies are able to travel many kilometres from their breeding place.

Typical breeding sites for houseflies are refuse and decaying organic matter. The female housefly lays around 600 eggs at a time, which hatch within 48 hours and it takes less than two weeks for an egg to pass maggot and pupal stages to become an adult in warm weather conditions. The blowflies usually breed on decaying matter of animal origin, especially meat or fish. Fruit flies generally occur in ripening fruits, bakeries, fruit canning facilities or fruit storages, beer cellars, or may be unwashed milk bottles. The control is carried out with removal of breeding materials.

Wasps

Wasps are usually contaminate foods through transmitting bacteria from their legs or bodies which are a major nuisance in bakeries under warm weather.

Cockroaches

There are different types of cockroaches available in different parts of the world based on different weather conditions.

German cockroach – Blatellagermanica

The adult is about 12-15mm long and colour is yellowish brownor light brown, which is one of the most common cockroaches worldwide and is easily identifiable by two dark stripes on the pronotum (head shield). It prefers warm, humid conditions but can infest food production areas and equipment, food storage areas, kitchens,bakeries, hotels vehicles, offices and administrative areas, bathrooms and especially ship’s galleys. The female can produce around 300 eggs in entire life span of 3 to 12 months. They are good climbers and can climb vertical glass and tiled surfaces, so can spread quickly.

American cockroach – Periplanetaamericana

The largest cockroach that may infest facilities; adults are 35-50mm long and reddish brown. It requires warm, humid environments to survive. They are found in drains, sewers, basements, storage rooms and waste storage areas.

Oriental cockroach – Blattaorientalis

The adult is grows around 20-30mm long, which are shiny dark brown to black in colour. It prefers cooler, dark and damp places to shelter, such as basements and drains, and can be found in storage rooms and waste storage areas. They are poor climbers on smooth surfaces but are cold tolerant (i.e. UK) and can be found outside buildings in drains, sewers, and external brickwork andusually found in cellars, kitchens, bakeries, hotels, etc.The eggs are laid with case which take about two months to hatch at 25ºC, and it will be prolonged in the colder climates. The female produce around 150 eggs in the entire life cycle which usually take between 6 to 12 months to become adults depending on the climatic condition and the food supplies.

Brown banded cockroach – Supellalongipalpa

The adult is only 1015mm long and looks similar to the more common German cockroach. It needs hot humid conditions, around 27°C, to survive and outside warm climates will infest heated buildings and appliances such as light switches and electrical appliances.

Australian cockroach – Periplanetaaustralasiae

A large species similar to the American cockroach. Adults are 25-35mm long with a reddish brown body and paler band around the pronotum (head shield); it is common in tropical climates (probably native to Africa, not Australia) but can survive in colder countries in warm, humid buildings such as greenhouses.

The cockroaches usually live in groups which are omnivorous, nocturnal creatures that gives an unpleasant characteristic odour. They are usually hide during the day time inside cracks, crevices, ducting, false ceilings, behind hot water plumbing, electrical equipment, behind skirtings and broken tiles. They can be detected with the presence of fecal matter, or their smell and they don’t fly. There are over 40 pathogenic organisms have been isolated from their bodies or from the fecal, including food poisoning organisms such as salmonella, clostridium perfringens, Listeria, Staphylococccus, and fungi, viruses as well as parasitic worms. They feed on decaying matter, mould, faecal matter in sewers, from rodents and birds, and animal carcasses, which can then be transmitted into the food production, storage and display areas on their bodies or in excreta; they defecate along their pathways; they frequently expel saliva on surfaces to ‘taste’ their environment; droppings and bodily secretions stain and leave a foul odour that can permeate infestation areas, food and packaging; cast skins and egg cases contaminate products and packaging; droppings and shed skins contain allergens, and heavy cockroach populations can trigger asthma attacks.Their presence can be detected through live or dead bodies, nymphs/moths, eggs, larvae and pupae, droppings, egg cases and smell or webbings (moths).

Psocidsor Booklice

Psocids are small insects with 1 to 2mm in size, and colour can be varied from cream, light brown to dark brown, which are omnivorous creatures that infest flour, grain, nuts, chocolate, fish and meat products. They also feed moulds and yeasts where infestation may be associated with packaging materials and pellets. The presence of booklice usually can be detected in high humid areas.