Cleaning sanitation and pest control

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Contents

Overview 3

The importance of pest control 4Types of pests 6Stored product pests 14

Cleaning and sanitation 18Requirements for cleaning 18Water 18Detergent 19Sanitizing 23

Cleaning and sanitizing programs 27General cleaning method 27

Summary 32

Glossary – Pest control 33

Glossary – Cleaning and sanitation 34

Answers to activities 35

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Overview

Food handlers need to be familiar with the requirements for pest control and effective cleaning and sanitation to ensure that food safety hazards are controlled.

In this topic, you will learn how to:

prevent and minimise potential health risks caused by the pathogens they harbour

reduce damage, loss and wastage due to contamination caused by pests

avoid prosecution because of the presence of pests on your premises

maintain your customer satisfaction.

Also, remember that good cleaning is important because it:

extends the storage life of raw and processed products

reduces the risk of the product being involved in outbreaks of food poisoning

reduces the number of product rejections, returns and complaints

reduces maintenance costs and lost time through breakdowns by regular dismantling and checking of equipment

reduces the environmental contamination with micro-organisms

improves working conditions and encourages better hygienic practices by employees.

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The importance of pest control

We refer to these pests as vermin and they should be eliminated from the food premises. They generally inhabit unsanitary environments such as toilets, garbage areas, drains, sewers and any unseen, inaccessible places.

Because of these surroundings, vermin will pick up dirt and potentially dangerous micro-organisms (pathogens).

This contamination can then be transferred to the food handler, food or surfaces and utensils used in food preparation. Such contamination increases the potential for transmission of disease and food poisoning.

Why control pests? There are many reasons for ensuring that food premises are kept free of vermin.

The main reasons are summarised below:

To prevent or minimise the potential health risk: flies, cockroaches, rats and mice are known to carry and spread many illnesses and diseases such as polio, typhoid, dysentery, diphtheria and food poisoning.

To reduce damage and loss due to wastage: contamination (infestation) with these vermin causes widespread damage.

Effective pest control will help to maintain the financial viability of food businesses.

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Activity 1

How many hygiene problems can you find in the illustration below? Write your list under the illustration.

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Check your feedback at the end of this topic.

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Types of pestsThere are many types of pests that may cause problems in food premises, for example:

cockroaches

flies

rodents (rats and mice)

weevils, beetles, moths and other insects.

The last category of pests is sometimes referred to as stored product pests. Although they don’t generally pose a health risk, they are still unacceptable in food and food premises.

How to control pests

The following are the main points to remember regarding pest control:

Good hygiene and sanitation in well-maintained food premises will go a long way in limiting the number of pests.

Prevention of entry by use of effective screens, vermin proofing, design and construction of premises will reduce pest problems.

Regular treatment and maintenance of pest control programs, and quick action to eliminate infestations if detected, are also advisable.

In other words:

don’t feed pests

don’t provide shelter for pests

destroy pests.

Only by implementing the above practices will food handlers be able to control undesirable pest problems.

Cockroaches

Cockroaches are probably one of the worst problems for business. Not only do they eat the food and not pay their bill, but they leave all sorts of nasty little surprise packets behind. Their presence also excites the local food safety officer/auditor into a state of persecution frenzy, which can also cause you big bucks in fines and more lost business!

Some very ill-informed people say that cockroaches are not dirty. This could not be further from the truth. Like most other vermin, they frequent and inhabit very unclean and unsanitary environments. You find them living

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in drains (including sewers), garbage areas, behind and underneath dirty, dusty and greasy ovens, fridges, sinks, and the like.

Their bodies will pick up disease-carrying micro-organisms from these environments. They are not fussy about what they eat and will happily eat any contaminated, rotten old food or anything else that provides them with nutrients (and there is plenty of goodness in the waste flushed down the sewer—it makes a great fertiliser).

These dirty little creatures will then walk all over your preparation benches, shelves and utensils, scattering dirt and disease all over the place as they go. They also have another particularly nasty party trick they save for any food you may have left out: they do not have a very well developed digestive system. In order to fully break down their food, they regurgitate their food then re-eat it.

They may perform this little act on some food you left out on the kitchen bench. And if vomiting over food is not bad enough, just think about the consequences if they had been previously dining on some dirty great big piece of waste down the sewer!

If you require further convincing, have a look at colour print numbers 1 and 47.

Types of cockroaches

Although many species of cockroaches exist, only a few varieties cause problems. Below are details of the main cockroaches infesting food premises.

Types of cockroaches Preferred habitats

German cockroach (Blatella germanica)

This cockroach prefers warm, dry places with ready access to water, such as kitchen cabinets and inside the back of refrigerators. An excellent climber, it is often found above ground level. It is rarely found outdoors. Although it is small it is the most common and persistent pest in food handling premises.

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American cockroach (Periplaneta americana)

American cockroaches prefer warm, damp places such as sewers, wood piles and garbage bins. This is the largest and best-known cockroach.

Smoky-brown cockroach (Periplaneta fuliginosa)

Smoky-brown cockroaches prefer a warm, humid climate. They frequently invade buildings from gardens, through doors, windows or other entrance points.

Australian cockroach This cockroach is similar to the American cockroach, though smaller.

Brown-banded cockroach This cockroach is similar to the German cockroach, but likely to be found in all parts of a building.

Figure 1: Types of cockroaches

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The life cycle of cockroaches

Cockroaches are good survivors and very rapid breeders. After mating, the adult female produces an egg case in which dozens of cockroaches develop. The egg capsule is either carried by the female or deposited, generally near a food source. If carried, as with the German cockroach, the capsule may be seen projecting from the abdomen. The egg case is small (approx 5–10 mm), oval, capsule-like and glossy.

The baby cockroaches, known as nymphs, hatch out of the egg case after a few weeks (depending on temperature). They continue to grow through a series of moultings over a period of months until they reach maturity and repeat this life cycle.

Figure 2: Life cycle of a cockroach

Control of cockroaches

Good hygiene and sanitation is the first line of defence to reduce infestations of cockroaches. Floors, walls, and so on should be kept free of cracks and gaps to deny cockroaches access and hiding places. Carelessness and uncleanliness provide these insects with food.

Eradicating cockroaches

There is a wide range of methods available to eradicate cockroaches:

While making premises less attractive to cockroaches through lack of food and shelter is the most effective approach, usually a few

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cockroaches will enter somehow and find food and shelter. The use of poisons to eradicate or exterminate them may be necessary.

Spraying aerosols is a waste of money for cockroach control unless sprayed directly onto the insect. Aerosols will not penetrate places where cockroaches usually shelter.

Spraying surface sprays near areas cockroaches may inhabit is usually the most effective method. Spray these near cracks and crevices, around fridge motors, under sinks and other enclosed areas. Dusts may sometimes penetrate enclosed areas more effectively. Don’t apply any insecticide to areas which may come in contact with food. Surface sprays and dusts are usually based on organophosphate insecticides.

Sticky traps can tell you if there is a problem, but are unlikely to control a serious infestation. Baits may be effective if all other available food is removed.

The use of professional pest controllers is recommended since they are best qualified to bring the situation under control. The use of residual surface sprays, specifically for cockroaches, is recommended to get the best results.

Fumigation can be effective but is expensive and inconvenient; this must only be undertaken by professional pest controllers. And remember, any extermination method can only kill pests—it cannot prevent more pests entering and staying.

The use of insect growth regulators is another method of controlling insects, including cockroaches. These chemicals prevent the development and breeding of the insect.

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Activity 2

1 What are the main indicators of pest and hygiene problems?

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2 Do you think these indicators are a problem for commercial food premises?

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Check your answers with the feedback at the end of this topic.

Flies

Flies feed on both rotting material and foodstuffs and carry micro-organisms from one to the other, either on their feet or on their hairy legs. They feed by vomiting onto foodstuffs then sucking up the liquid food.

The life cycle of flies

The common house fly breeds in decaying matter and manure. The female lays batches of eggs that hatch into tiny white legless larvae (maggots) in 8 to 36 hours. When fully grown, a larva migrates to a drier, cooler site where a pupa is formed. Within a few days the adult fly emerges. It has a life expectancy of one to three months depending on weather and temperature.

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Figure 3: Life cycle of the common house fly

The life cycle of other flies which present problems in different areas, such as the fruit, ferment or vinegar fly (Drosophila species), the bush fly (Musca vetustissina), and buffalo fly, are similar to that of the house fly. Blowflies are common in country areas and are generally carrion eaters. Their life cycle is similar except that some varieties may deposit larvae directly onto foodstuffs and there is no egg stage. Generally speaking, blowflies enter premises accidentally and spend most of their time trying to get out again.

Control of flies

Listed here are several ways to prevent flies from entering premises.

Suitably screening all openings will keep flies outside.

Air curtains are effective in doorways where traffic may be heavy.

Strict hygiene will reduce the attraction of the flies to a potential food supply.

Eradicating flies

There are two popular ways to eradicate flies:

Electrical fly traps work on the principle of attracting the flies—and other insects—to a ‘blue’ light through an electrical grid. They are then electrocuted when they touch the grid.

‘Knock down’, quick killing insecticides can be effective. These usually contain synthetic or natural pyrethrins which have a low toxicity as well as being fast acting. All food must be removed or covered before insecticides are used and the premises must be thoroughly cleaned before re-use.

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Rodents

Rodents such as rats and mice also present a major problem to the food industry. Rodents are known carriers of a number of diseases and food poisoning micro-organisms. Because of their feeding habits, they carry bacteria from rubbish, sewers and other dirty sites to food establishments, and food if it is left out. They will also leave their droppings (faeces) and because of poor bladder control, will urinate over benches and anything (including food) they travel over!

Signs of rodent infestation are usually damage to food or packaging, or finding droppings. These are very dark and the size is about twice as large as a grain of rice in the case of rats and about the same size as a grain of rice in the case of mice.

The main rodents that cause problems are house mice, as well as the brown rat and the smaller black rat.

Figure 4: The common rat—Rattus rattus

The life cycle of rodents

Rodents are prolific breeders and, if conditions are suitable, population explosions are common. The average litter is about six and normally at least six litters can be expected each year.

Control of rodents

It is much easier to prevent rodents from entering premises than to get rid of them.

PreventionBuildings should be constructed so that all entrances are properly sealed. Within the building, fittings should be constructed so they don’t offer any

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hiding places. Good lighting and proper ventilation will also discourage rodents.

Rubbish, which is a potential hiding or nesting place, should not be allowed to accumulate. Rats are capable of foraging for food over a fairly wide area. Mice rarely move more than a few metres from their nesting site once this is established, because they dislike moving across open areas.

Good hygiene procedures will discourage rodents. Food scraps should be removed and placed in sealed containers. All food should be stored in containers, about 45 centimetres above the floor.

Eradicating rodents

The following steps will help to eradicate rodents:

Clean out premises to minimise hiding places.

Remove rubbish from around the premises.

If only small numbers are involved then a trapping program could be effective. The type of trap and the bait used will depend on the rodents present and the type of food they appear to favour. For example, if rodents have been feeding on meat scraps and fats, cheese may not be attractive to them. Rats are generally wary of traps unless they have been set out for three or four days without bait.

Poisons are commonly used where the numbers are large or potentially large. Poisons can be divided into two main categories—acute and chronic.

Acute poisons are available but most are non-specific and accidental poisonings of domestic pets and people have occurred. Their use should be carefully controlled by a skilled operator and they should not be used near food.

Chronic poisons are now commonly used and are very effective. Anti-coagulants can be used by unskilled operators. It is usually necessary for the poison to be taken up over a period of three to seven days before it is effective. It will completely eradicate a heavy infestation in one to two weeks. Accidental consumption on one or two occasions is not necessarily serious.

The poisons (rodenticides) are usually prepared as a wet or dry bait. The baits consist of cereal, vegetable or flour and melted fat, and are coloured a distinctive blue or green. The baits are placed in a bait box which is clearly marked ‘Rodent bait’ and closed on all sides, with openings only large enough to allow rodents to enter. Spillage of rodenticide must be avoided.

Care should be taken in the storage and usage of poisons. They should be packed in distinctive containers and be properly labelled.

Fumigation is perhaps a last resort and should only be attempted by skilled operators. The gases used are highly poisonous to humans and it

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is necessary to get approval from the NSW Health Commission before use. Fumigation cannot be used in premises where meat is stored.

Colour print numbers 4 and 48–50 show various problems with rodents.

Stored product pestsThere is another category of insects which also cause great problems to the food handler, known as stored product pests. These do not generally present a direct health risk. However, they are of great concern since food contaminated or infested with stored product pests, such as weevils, moths and beetles, are considered to be spoiled and unfit for human consumption.

Foods affected

Many foods can become infested, but some particular favourites are mentioned below:

Grain products such as wheat, rice and corn are quite often attacked by beetles or weevils.

Flour and cereal-based products such as pasta, breakfast cereal, cake mixes and dried food mixes are favoured not only by beetles, but moths will also set up home in them.

Many other foods, particularly dried and semi-dried foods, are also attacked by stored product pests. Some of these foods are:

chocolate dried vegetables dried fruits such as apricots and sultanas spices and dried herbs packet foods, soup mixes, sugar, tea and nuts.

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Types of stored product pests

There are many stored product pests, such as moths, beetles and weevils.

Beetles and weevils

Figure 5: Flour beetle and rice weevil

Weevils and beetles are among the most destructive of the stored product pests. Even though they are small (2–5 mm), their strong jaws can easily penetrate the hard outer skin of grains and cereal products, as well as nuts.

Their life cycle involves the adult weevils laying their eggs in the food product. The lava or grub hatches out of the eggs. The lava then forms a case or pupa from which the adult weevil breaks out.

Moths

Grain or cereal moths also infest most cereal-based foods, such as flour and breakfast cereal, oats, and so on. They are only small (10–15 mm long) and may go unnoticed until you spot one of their young caterpillars on the end of your spoon, just when you are finishing your bowl of muesli!

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Figure 6: A moth and its caterpillar

The life cycle of moths involves the adult laying eggs, from which the caterpillar hatches. The caterpillar, after considerable eating, forms a cocoon (webbing) from which the adult moth emerges, ready to start the cycle all over again.

Control of stored product pests

Here are some suggested ways for controlling these pests.

Check incoming stock for any signs of infestation.

Monitor stock, particularly the more susceptible dried foods and cereal products.

Discard any food or packages as soon as they show signs of infestation. Leaving just one packet of contaminated flour will allow the moths or beetles to spread to other food products.

Clean up any spillages immediately.

If packaging or seals become broken or damaged, discard or re-package the contents.

The pests gain all their moisture from the food, so cannot grow or breed if food is kept very dry.

Observe strict stock rotation. The longer stock is kept, the greater the possibility of it becoming infested.

The temperature of the storeroom is also very important, since insects will breed much faster in warm, moist conditions. Pests can be killed by putting food in a freezer.

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Now have a look at coloured print numbers 51–54 for further examples of stored product pests

Activity 3

1 Outline the life cycle of the cockroach and indicate why it is considered a health risk.

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2 What is the best method to control vermin in food premises?

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3 List three stored product pests.

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4 List three methods of applying of insecticides and comment on the effectiveness of each method against flies and cockroaches.

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Cleaning and sanitation

Cleaning is essential to ensure food safety. There are many reasons that cleaning is important. Here are some of them.

It helps to ensure the food and premises are wholesome and clean. Your customers will not come back if you serve them dirty food on an unclean plate.

It reduces the incidence of pest infestations.

It helps to preserve the safety, freshness and palatability of the product by removing and restricting microbial activity, and also helps to decrease the incidence of food poisoning.

Can you think of any more?

Requirements for cleaningThe following are needed for effective and efficient cleaning:

Water

Detergent

Sanitizer

Suitable construction and design and a plan for a clean working environment

WaterWater is a fundamental tool for cleaning. It is important that it is of sufficient quantity and adequate quality.

Water used for cleaning in food premises should be of standard fit for drinking, that is potable.

Finally, apart from the water being clean to start with—and plenty of it—the temperature of the water is also important. A plentiful supply of hot water is essential.

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DetergentAfter water, detergents are the next most important factor in effective cleaning. There are many different types of chemical detergents. Some may be more effective than others, but they all work in a similar way as outlined below.

How detergents work

The word detergent is derived from a Greek word which means to clean. In everyday language, we tend to call our cleaning materials either soap or detergent. However, soap is technically a detergent. In fact, anything which can clean is a detergent.

Detergents, such as soap and other liquid or powdered detergents, work by using the special properties of the surfactant they contain. If it were possible (which it isn’t) to magnify a single, tiny, tiny part of the detergent sufficiently, you would see individual molecules.

The molecule of a surfactant is large and has, at one end, a water-soluble part and, at the other end, a fat-soluble part as shown in the diagram below.

When such a detergent is added to water, the water-hating ends immediately try to get away from the water by going directly to the surface as illustrated below. This enables water to spread evenly over the surface, distributing the detergent to places where it is required.

Figure 7: The action of detergent molecules on water and surfaces being cleaned

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Detergents alone will not remove the dirt from the surface. For this, mechanical action is required. The molecules of the detergent reduce surface tension and help the mechanical action to remove the dirt.

This mechanical action can be high pressure jets, a brush, rapid movement of the item to be cleaned, or any other method of scraping or rubbing the surface. As the dirt is removed, it is surrounded by the detergent molecules. These molecules give the dirt particle an electrical charge which means the particles of dirt will repel each other.

This process is illustrated below.

Figure 8: Removal of dirt by detergent

Here you can see the action of detergent molecules on a dirt particle. This prevents the bits of dirt being removed from the surface from re-depositing on that surface.

The illustration below shows in a little more detail the washing process using detergent. The article shown is a spoon, but the principle is the same for any other surface. (Hot water assists the detergent molecules to remove and suspend dirt.)

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Figure 9: Processes involved in detergent action on dirt

Types of detergent

There are many different types of detergent. For example, detergents that may be very effective for removing the build-up of grease and fat from the inside of an oven may not work so well if used to clean other surfaces. In fact, they may damage certain surfaces if used for cleaning jobs they are not intended for; some can even be dangerous or corrosive if not used correctly. In addition, the type of dirt is important in determining which detergent to use.

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Types of dirt or soil

Generally, we can classify soils or dirt according to whether they are organic or inorganic.

Organic soils are derived from animal or vegetable matter, for example, oil, fat, grease, protein, sugar, starch and cellulose.

Inorganic soils are derived from other substances such as grit, salt, rust and hard water scale.

What detergent works best with what dirt?

Alkaline or neutral detergents are best suited to removing organic soils. Acid detergents are suited to removing inorganic soils.

The main types of detergent are summarised below.

Acid detergents

These are only used to remove inorganic soil by reacting chemically with the soil to form water-soluble substances. They are used when cleaning porcelain such as sinks and toilets where abrasives or alkaline detergents could damage the surface, and for descaling urns and so on. Acid detergents are not very effective for removing grease and so are the least commonly used detergent.

Alkaline detergents

These are used to remove organic soil. They do so by reacting chemically with protein, fat, grease and so on, to form a water-soluble substance. Note that they are corrosive to the skin and will damage aluminium. Mildly alkaline detergents may be suitable for manual cleaning methods. Gloves should be worn.

Highly alkaline detergents may be suitable for cleaning really dirty surfaces such as ovens and in dishwashers, but remember that personal contact with them will cause burns. Also, take care as they may dull crystal glassware and corrode aluminium cookware.

Neutral detergents

These are used to remove organic soils and general dirt. They do so by removing the soil from the surface, dispersing it into small pieces and suspending it in water. They do not react chemically with the soil.

Neutral detergents do not burn the skin, so are used for manual cleaning.

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Finally, although detergents can remove micro-organisms from the surfaces being cleaned, they are not designed to kill them. In order to reduce the numbers of micro-organisms by killing them, we need sanitizers.

SanitizingAs previously mentioned, detergents on their own will not kill micro-organisms. Sanitizing is necessary to kill micro-organisms or reduce their overall numbers to levels considered to be safe.

Sanitizing involves treating the surface (usually after it has been cleaned) to reduce or eliminate the micro-organisms present. Sanitizing of surfaces can be carried out using either:

high temperatures to kill micro-organisms on surfaces, or

addition of chemicals to kill the micro-organisms—that is, sanitizers.

Heat

Heat, as stated in previous sections, is very effective in preventing the growth of micro-organisms and in killing living microbial cells.

Very hot water (77–82°C or above), or steam if it is available, is used to effectively sanitize surfaces in food handling premises.

If heat is used, it is important to allow sufficient time to kill the micro-organisms. Although most of the micro-organisms are killed, there are some, such as the very resistant spore-forming bacteria, which may still survive.

Heat is very effective, but cannot always be used: Water at 77°C will cause burns, it is difficult to keep water at this temperature and hot water from a tap is often not this hot.

Some surfaces, such as benches or floors, cannot easily be heated. If heat is not used, then chemical sanitizers can be utilised.

Sanitizers

There are different types of chemical sanitizers available. These are substances which are toxic to micro-organisms. Care must be exercised in their use because large amounts could be toxic to humans and, if they come into contact with food, they can contaminate it. Care must be taken during storage and use to prevent this from happening.

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Correct methods for using different types of sanitizers

Sanitizers take time to kill microbes, so follow instructions. Some sanitizers are inactivated by other chemicals or by dirt or are effective over a limited pH range. Many sanitizers fail to kill some types of micro-organisms.

Halogen (chlorine, iodine, bromine)

Chlorine-based products are the most commonly used sanitizers. Chlorine is cheap, effective, easily rinsed off, easily tested for strength and traces on food are harmless to consumers. Chlorine is very toxic to micro-organisms and only very low concentrations are necessary to control them; 50 parts per million is a typical minimum effective concentration. However chlorine may be affected by dirt and other chemicals and by temperature and pH, so follow instructions carefully.

Iodine-based sanitizers may also be used. Iodine can be formulated into a sanitizer called an ‘iodophor’. Rinsing off with fresh water is necessary when using these sanitizers to ensure that there is no trace left to contaminate the food.

Pine and eucalyptus oils

These are quite effective but are expensive and have a strong odour so use on food handling equipment is limited.

Quats

Quaternary ammonium compounds, to give their full name, are another commonly used sanitizer. They have the advantages of low toxicity, low corrosiveness, stability in storage and some cleaning (detergent) ability.

They are often used where one-step cleaning/sanitizing is required. They are effective where surfaces are not very dirty and any remaining on the surface is not toxic. Benzalkonium chloride is the active ingredient in the well known Pine-o-cleen and many other combined detergent/sanitizers.

Disadvantages are a higher cost than chlorine and the possibility that not all types of bacteria are killed.

Peroxyacetic acid

This compound has been used as a sanitising/wash rinse in products like bean spouts and salad vegetables. The level used may vary (20-2000ppm) with the Peroxyacetic acid (CH3COOOH) breaking down in solution forming the active sanitising agent, ie Hydrogen peroxide (HO-OH) which then attacks (oxidises) any organic matter such as bacteria.

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Alcohol or phenol-based sanitizers

Triclosan or chlorhexidine are in many anti-microbial hand washing liquids and some surface sanitizers and dishwashing liquids. Triclosan is included in some sponge wipes at manufacture to help prevent bacteria growing in them. Inclusion of Triclosan in plastic cutting boards or containers inhibits growth on the plastic, but not on the food.

Phenol-based chemicals are commonly used as disinfectants in non-food applications. Although effective, some have a rather strong smell which would contaminate food. If you have ever used products like Dettol you would have experienced this smell.

Three parts denatured ethyl alcohol (methylated spirits) to one part water is a good surface sanitizer for spraying on dining tables. It dries quickly, but be aware as it is inflammable!

Propyl alcohol (propanol) is an ingredient in some kitchen cleaners/sanitizers, and in wipes used to sanitize thermometers etc.

Always take care when handling chemicals:

Some are toxic.

Some are corrosive and will damage surfaces, clothing and your body.

Some chemicals when mixed will react with each other and neutralise the effectiveness of both.

Some mixtures give off toxic gas (eg chlorine) or may even cause fire or explosions.

Always follow the manufacturer’s directions!

This may include using protective clothing, well-ventilated areas, adding chemical to water not water to the chemical and measuring quantities carefully.

Never mix chemicals (unless directions on the container say specifically that it is acceptable to do so).

How much sanitizer to use

The Victorian Dept of Health indicates that utensils and surfaces should be sanitized using 50–100 mg/L (ppm) chlorine solution. The table below shows how much food grade chlorine solution to use.

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How much water?

How much bleach?

Household bleach (4% chlorine)

Commercial bleach(10% chlorine)

Concentration required

50 ppm 100 ppm 50 ppm 100 ppm

5 L 6.25 mL 12.5 mL 2.5 mL 5 mL

10 L 12.5 mL 25 mL 5 mL 10 mL

50 L 62.5 mL 125 mL 25 mL 50 mL

Also note that adjusting the pH of the chlorine sanitising solution to approximately pH6 will improve the effectiveness of the process. For example, when making up 5L of 1200ppm solution you can add 15ml of vinegar.

Activity 4

The following questions will help your understanding of the work covered so far.

The answers are at the end of this section.

1 Describe a detergent (surfactant) molecule.

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2 What is the difference between a detergent and a sanitizer?

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Cleaning and sanitizing programs

General cleaning methodMost cleaning procedure can be summarised as set out below. Steps may be skipped or combined in particular instances.

1 Pre-clean. A pre-clean involves removing any obvious, large easy-to-remove dirt. This could simply mean sweeping the floor before washing it, wiping down a bench top used for preparing food to remove any crumbs and bits of food and scraping off plates, pots and pans.

2 Wash with clean water using the correct detergent. The selection of the detergent depends on the nature of the surface and the dirt to be removed; each schedule will specify the best detergent to use.

Physical work is usually necessary to remove dirt and suspend or emulsify it in the water. This may involve simply good old elbow grease. Mechanical action such as scrubbing or high-pressure water spray may also be utilised. Heat is usually required. Generally, water should be at least 45°C to melt fats and assist the chemical action of detergents.

3 Rinsing removes dirt and detergent from the surface being cleaned. If it is not rinsed off it may accumulate on the surface and the action of sanitizers may be affected. (One example of inadequate rinsing is clear in licensed premises. It makes your beer go flat!)

4 Sanitize if necessary. When heat or chemical sanitizer is used, it is essential to allow sufficient time for either to be effective. Commercial dishwashers use very hot water (>77°C) or chlorine in their rinse cycle.

5 A final rinse if a chemical sanitizer has been used. This may not be necessary if heat sanitizing has been employed.

6 Leave the surface dry. This is very important as micro-organisms may grow in wet conditions as wet surfaces; will also attract more dust and dirt.

The above is just one example of a general cleaning method. It may vary depending on the application.

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Removable equipment

Removable equipment such as cutting boards, buckets, trays etc should be treated in the following manner.

1 Dry clean then rinse with water.

2 Scrub until clean in hot water (minimum 45°C) containing neutral detergent until all dirt is removed.

3 Rinse with clean hot water (minimum 45°C).

4 Sanitize with chlorine (follow pack instructions for concentration, time and temperature).

5 Rinse with hot water (minimum 45°C).

6 Place each item in a position to drain and allow air-drying. Do not stack until properly dry.

Polythene cutting-boards are liable to have a scored surface which is difficult to clean and sterilise. For this reason they are a potential source of contamination and should be treated regularly through the working day to prevent a build-up of micro-organisms. They should be re-surfaced using a belt-sander at regular intervals.

Where ever possible, use impervious contact surfaces to minimise microbial harbourages.

Dishwashing requires that procedures are carefully verified unless commercial dishwashers are used. These are generally effective and sanitize by using a high temperature of at least 77. Domestic dishwashers use lower a temperature but may be satisfactory as cycle times are longer. When washing utensils manually it is usually impractical to maintain a water temperature hot enough to sanitize effectively so chlorine is a more effective method; 50 ppm chlorine is generally effective, though this should be verified for particular conditions.

What information should cleaning programs include?

In addition to the above information, a cleaning program should include:

information on frequency of cleaning

what chemicals to use

temperatures

what equipment is needed

how to dismantle equipment to be cleaned

safety precautions.

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The cleaning program should also nominate the person responsible for the cleaning. A record of completion of cleaning is often useful evidence that will help support food safety auditors.

Cleanliness tests

There are a number of simple tests that can be used to see if a surface is clean.

There should be no visible contamination.

The working surfaces should not feel greasy or rough.

When a clean, white tissue is rubbed over the surface it should not be discoloured.

The area should be free of abnormal odours.

Microbiological testing

More sophisticated micro-biological tests are sometimes used to determine the actual number of micro-organisms left on the surface. These involve sampling a section of the surface being cleaned and determining the micro-organisms left.

Below are some examples.

Measure of cleaning

Measure of sanitizing

Surface bacterial count 6.3cm

(1 square inch)

Surface washed not sanitized

Surface washed and sanitized

less than 1 satisfactory satisfactory

less than 10 satisfactory borderline

10 to 100 borderline contaminated

100 to 1000 poor cleaning contaminated

Microbiological testing is the definitive test as to whether cleaning has been effective. However it takes time—typically 24 hours or more—to get results from microbiological testing, so this is mostly used as a reference test.

The Australian Standard HB224:2001, Appendix C states that ‘as a guide an adequately cleaned and sanitized food surface should not have more than 100 colonies per utensil or per area of equipment swabbed (10cm2)’.

For immediate results, the above simple tests are an indication and may suffice for some surfaces. A better indication of cleanliness can be gained by testing for organic matter on the surface. Test kits are commercially

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available which indirectly determine the presence of microbial contamination by detecting the presence of protein or carbohydrate on a surface. Simply swabbing the surface and placing the swab in a ready prepared solution gives a colour reaction which easily interprets the effectiveness of the cleaning process that may (or may not) have occurred.

Now have a look at coloured print numbers 55–65, which show examples of appropriate and inappropriate cleaning.

Activity 5

The following questions will help your understanding of the work covered so far.

1 List the main steps in the generalised cleaning method.

______________________________________________________________________

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2 What information should be covered by a cleaning schedule?

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______________________________________________________________________

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3. The following terms featured in this topic. Jot down their meanings in the second column. These are important terms so it would be a good idea to work through the section again if you are unsure of their meaning.

Word Meaning

acute poison

chronic poison

humidity

rodents

stored product pests

vermin

acid

alkaline

corrosive

inorganic

molecule

neutral

organic

potable

sanitizer

toxic

water soluble

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Summary

Now that you have completed this topic you should be able to advise food handlers how to:

prevent and minimise potential health risks caused by the pathogens they harbour

reduce damage, loss and wastage due to contamination caused by pests

avoid prosecution because of the presence of pests on their premises

maintain customer satisfaction.

Also, remember that good cleaning is important because it:

extends the storage life of raw and processed products

reduces the risk of the product being involved in outbreaks of food poisoning

reduces the number of product rejections, returns and complaints

reduces maintenance costs and lost time through breakdowns by regular dismantling and checking of equipment

reduces the environmental contamination with micro-organisms

improves working conditions and encourages better hygienic practices by employees.

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Glossary – Pest control

acute poison kills with one dose.

air curtain fan blowing air downwards over a doorway to reduce movement of heat and pests through the opening.

carrion dead and putrefying flesh.

chronic poison repeated doses are necessary to kill; safer than acute poisons.

Drosophila vinegar fly, ferment fly or fruit fly; not to be confused with the Queensland fruit fly.

knock-down rapid acting (insecticide etc).

larva first stage after egg in life cycle of many insects (eg grub, caterpillar, maggot).

nymph immature stages in life cycle of insects which do not form larva and pupa (eg cockroaches).

pupa resting stage between larva and adult in insect life cycle.

residual insecticide one which is relatively long lasting; often applied as a spray on surfaces or as a powder or ‘dust’.

rodent group of animals including rabbits and guinea pigs as well as pests such as rats and mice and many other animals.

vermin pests—animals and insects.

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Glossary – Cleaning and sanitation

acid a substance containing hydrogen ions, strong acids are corrosive, especially to metals. Acids taste sour.

alkali a substance containing hydroxide ions—strong alkali which is corrosive to fats and proteins.

buffer a substance which resists change in pH.cleaning the process of removing any unwanted contaminating materials (grease, dirt,

food, dust, stains, and so on.) from any surface of equipment, utensils, and so on.

cleaning schedule a statement of cleaning methods and frequency.detergents a product used to remove dirt and some micro-organisms from the surface

being cleaned. We shall be studying detergents in more detail later in this section.

disinfect to kill or remove infectious micro-organisms. Often applies to skin, wounds, and so on.

disinfectant chemical used to kill microbes. Used in non-food areas; often has strong odour.

hard water water containing calcium or magnesium salts. Hard water reduces effectiveness of some detergents, especially soap.

emulsion a suspension of fine particles of oil in water, or water in oil.hydrophilic literally ‘water-loving’. Soluble in water but not in fat.hydrophobic literally ‘water-hating’. Soluble in fat but not in water.infect to contaminate with harmful organisms.neutral neither acid nor alkaline, ie pH7.particulate existing as particles.pH scale 0 to 14 used to measure the level of acidity and alkalinity. Strong

acid = 0, neutral = 7, strong alkali = 14.potable water suitable for drinking.sanitize eliminate micro-organisms or reduce their numbers to safe levels on the

surface; usually takes place after cleaningsanitizer chemical used to kill microbes. Suitable for use in food areas.sterilize totally eliminate or destroy micro-organisms; this is rarely required, or

carried out, in food premises.surface tension the tendency of the surface of a liquid to contract. It forms liquid into drops

and so reduces ability of liquid to spread over surface or ‘to wet’.surfactant ‘surface active agent’; a substance which reduces surface tension of water;

essential active component of most detergents.water softener a substance reducing the effect of hard water in making detergents less

effective.

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Answers to activities

Activity 1

1 How many hygiene problems can you list from this illustration? There are heaps!! For example:

Numerous cockroaches

Presence of cat, and mouse droppings (yuck!)

Benchtop appears to be made of porous material such as wood and is also covered with dirt and has a damaged surface

A person is obviously ill and has symptoms of the flu and may touch his nose and mouth with his hands whilst handling food

Clothing is soiled and in disrepair

Breach of building codes evident—for example, unsealed walls, insects, dust and other airborne particles could enter through open window.

Now find some more! And don’t eat food from that premises!

Activity 21 What are the main indicators of pest and hygiene problems?

visible appearance of cockroaches rodent droppings food left exposed to potential contamination and so on.

2 Do you think these indicators are problems for commercial food premises? Most definitely. All food premises should conform to all hygienic food-handling requirements.

Activity 31 Adult—egg case—nymph—adult, inhabits unsanitary

environment/harbours pathogens which can be transferred to food.

2 Preventive methods—that is good housekeeping, sanitation/hygiene, preventing entry and eliminating harbourings...

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3 grain weevil, confused flour beetle, Mediterranean flour moth.

4 (a) Fumigation—for total control, kills all vermin (and anything else around!).

(b) Aerosol sprays—general purpose for mainly flies (not very effective for cockroaches), contains pyrethrins.

(c) Surface spray—specific for cockroaches; the walk-on chemical is absorbed through skin (eg organophosphate chemical.)

Activity 41 The molecule of a surfactant is large and has, at one end, a water-

soluble part and, at the other end, a fat-soluble part . See Figure 7.

2 A detergent is an agent which assists cleaning (ie removes micro-organisms from surfaces). A sanitizer is a substance that reduces bacteria to safe numbers (ie kills micro-organisms).

Activity 51 (a) Pre-clean

(b) Wash(c) Rinse(d) Sanitize(e) Rinse(f) Dry

2 (a) How often and when cleaning is done?

(b) How to clean, and equipment needed?(c) What materials to use—detergent, sanitizer?(d) Dismantling of equipment for cleaning, if applicable.(e) Safety precautions necessary.(f) Who is to do the cleaning?

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