Royal Army College

Lesson Overview

After water, food is the next route by which disease enters a force. It sickens people in two ways: when the food itself is contaminated or spoiled, and when sound food is fouled by unclean handling. Because a meal is shared, one failure reaches everyone who eats it.

This lesson follows food through the field from store to mouth: sourcing and inspection, safe storage, thorough cooking, the cook's own hygiene and health, and clean serving and washing-up. It ends with the standard of a properly run field kitchen, and with the same standard applied to a relief kitchen feeding a stricken population.

The thread running through it all is one idea. Food-borne illness is almost wholly preventable, but only by an unbroken chain of plain disciplines. Leave the meat warm, skip the hand-wash, wash up in cold greasy water, and the chain fails. Each link below is taught with its reason, so it is kept when it is least convenient.

By the end you will be able to explain how food carries disease and why warmth makes it worse, source and inspect food so only sound food enters the unit, store food safely in field conditions, cook food so it is safe to eat, judge the hygiene and health a food-handler must keep, serve and wash up cleanly, and describe the standard of a properly run field kitchen.

This is the knowledge layer. Setting up and running a field kitchen to a safe standard is reinforced and certified in person, under qualified supervision. Treating those who fall ill from bad food belongs to the Combat First Aid course and to qualified medical staff.

Key Terms

Food-borne disease: illness caused by eating food that is contaminated, spoiled, or unsafely handled; a common, preventable cause of field sickness that can disable many from a single meal.
Food-handler: anyone who prepares, cooks, or serves food for others; held to a high standard of hygiene and health because their cleanliness protects the whole unit.
Contamination: the getting of disease germs, dirt, or poison into food, from dirty hands, dirty water, pests, dirty surfaces and utensils, or raw food touching food ready to eat.
Multiplication: the rapid increase of germs already in food when it is left warm; given only time and warmth, a few harmless germs become a dangerous dose.
The danger zone: the band of warmth, roughly between fridge-cold and properly hot, in which germs multiply fastest; the central rule of food safety is to keep food out of it.
Perishable (potentially hazardous) food: food that readily supports germ growth and so turns dangerous quickly, above all meat, poultry, fish, milk and dairy, eggs, and made dishes such as gravies, soups, and stews; it needs the most care.
Spoilage: the going-bad of food, shown by off smell, colour, or texture, or by a tin that leaks, bulges, or hisses wrong when opened; spoiled food is not eaten.
Cross-contamination: the passing of disease from one food, surface, hand, cloth, or utensil to another, as from raw meat or dirty hands to food ready to eat.
The hold: the keeping of cooked food warm before it is eaten; dangerous if long, because the warmth lets germs multiply, so cooked food is eaten promptly.
The field kitchen: the place where a unit's food is prepared, cooked, and served, sited and kept to a strict standard of cleanliness.

How food carries disease

Food is a route of disease for the same reason water is: it goes into the body, and whatever it carries goes in with it. It can do so by two paths. The first is the food itself, already contaminated or spoiled. The second is the handling, when food that began sound is fouled along the way. A clean food badly handled is as dangerous as a tainted one.

Name the routes and you learn to block them. There are four. Food is fouled by dirty hands, the commonest of all, when a handler touches food after the latrine, after touching the face or hair, or after handling raw meat, without washing in between. It is fouled by dirty water, when unsafe water is used to wash food, make up a dish, or rinse utensils, passing whatever the water carried straight into the meal; this is why kitchen water must itself be safe, the subject of Lesson 02. It is fouled by pests, the flies that walk from filth and waste to the food and the rats and vermin that foul stores with their droppings. And it is fouled by spoilage, when food is left until the germs already in it grow rank. Block these four, and most of the danger is shut out before cooking begins.

A fifth idea turns a small fault into a disaster: multiplication. Germs are living things, and given warmth and time they double and double again, so a few germs too small a dose to harm anyone become, in a few hours of warmth, enough to lay a person low. Food need not look or smell bad to be dangerous. A dish that seems perfectly sound can be swarming because it stood warm. This is why warmth is the enemy and why so much of the method below turns on temperature. Cooking kills the germs present; cooling and prompt eating deny the survivors the warmth to breed back to a dangerous number.

What makes food-borne illness so serious in the field is that it strikes a whole unit at once. The meal is shared. One contaminated dish, one unclean cook, one batch held too long, and everyone who eats falls ill together. The diarrhoeal and food-poisoning illnesses that follow, with vomiting, loose stomachs, and the dehydration they bring, can put many people out of action in a day, and the worst of them, the parasites in undercooked meat and fish, can sicken a person for a long time after. Food hygiene, like water discipline, is a guard set over the health of all.

Sourcing and inspecting food

The chain begins before the kitchen, with what is allowed into the unit, because no careful cooking redeems food that arrives unfit. Food reaches a small force as rations through proper supply, and, on relief tasks, sometimes from what is bought or offered locally. The discipline is the same: only sound food, from a source you can trust.

Food from outside the supply chain carries the most uncertainty, because you do not know how it was kept. As a rule, food, drink, and ice obtained locally are not used until approved by the medical authority or a competent food-safety check, since ice made from unsafe water or milk left unrefrigerated can carry disease as surely as foul water. Where no check is available, lean on food that is sealed, processed, and stable, and treat anything fresh, raw, or of unknown keeping as suspect.

Whatever the source, inspect it before storing or using, and learn the plain signs. Packaged and tinned food should be sealed and in date, the tin clean and undamaged: not rusted through, not dented on a seam, and above all not bulging, leaking, or hissing wrongly when opened, any of which signals the food has gone bad and may be dangerous. A bulging tin is discarded, not opened to check and not tasted. Dried goods, flour, and packets should be dry, whole, and free of damp, mould, and vermin; a chewed packet or droppings among the stores condemns what they have reached. Fresh and perishable food is judged by smell, colour, and texture: meat, fish, or made dishes that smell off, or have changed colour or turned slimy, are rejected. When any sign appears, or there is honest doubt, the rule is plain: when in doubt, throw it out. A discarded ration is a small loss; a unit laid low by a meal is a large one.

Handling and storing food

Food kept badly becomes dangerous before it is ever cooked, so safe storage protects all the care taken in sourcing. The governing idea is multiplication, and the rule that follows is the central rule of food safety: keep cold food cold, keep hot food hot, and keep food out of the danger zone in between.

The danger zone runs roughly from fridge-cold up to the heat of food kept properly hot for serving. Below it, in true cold, germs are slowed almost to a stop; above it, in real heat, they are killed. It is the warm middle that is deadly, and the longer food sits there the worse it becomes. So perishable food, meat and fish and dairy above all, is kept genuinely cold until cooked, by the coldest means the field allows; cooked food meant to be held is kept genuinely hot, not merely warm. The figure below fixes the rule.

   THE DANGER ZONE: WHY WARMTH IS THE ENEMY

   HOT            ^   cooking heat: germs are killed
   (keep hot      |   .........................................
    food hot)     |   hot-holding heat: food kept safely hot
   ---------------+-------------------------------------------
                  |
   DANGER ZONE    |   the warm middle: germs MULTIPLY fastest
   (keep food     |   ->  a few germs become a dangerous dose
    OUT of here)  |   ->  the longer food sits warm, the worse
                  |
   ---------------+-------------------------------------------
   COLD           |   fridge-cold: germ growth slowed to a crawl
   (keep cold     v   .........................................
    food cold)        frozen: growth stopped

   Rule: keep cold food COLD, keep hot food HOT,
         and never let food sit warm in the middle.

Food must also be protected from what would foul it in store. Keep it covered and up off the ground, away from dust, dirt, and weather, and guarded against pests, the flies and the rats and vermin that spoil stores; tins, dried goods, and packets too are raised off the ground and protected from damp and vermin. And keep raw apart from cooked: raw meat, fish, and their juices are kept away from and below cooked food and food to be eaten without further cooking, never above where they can drip down. Cross-contamination from raw to ready-to-eat is one of the surest ways to undo a safe meal. Stores are looked over regularly, and spoilage acted on at once: when in doubt, throw it out.

One discipline deserves its own warning, because it is the one most often let slip when people are busy: do not hold cooked food warm for long, and do not cook far ahead. Food left sitting in the warmth is food in which germs are multiplying, so a meal safe when cooked can become a hazard. Cooking hours ahead and letting the food stand is among the commonest ways a kitchen poisons its own unit. Cook close to the time of eating; serve and eat promptly; what genuinely must be kept is kept properly cold or properly hot, never warm; leftovers held warm in the field are not saved.

Preparing and cooking food

Cooking is the great safeguard, because heat destroys the disease food carries, but only food cooked thoroughly. Cook food right through, not merely to colour the outside. Meat, poultry, and fish can carry disease, including the parasites that cause long illness, in parts the heat has not reached. Food brown without but raw within is a common cause of food-borne illness, and the thicker the piece, the greater the care needed to reach the centre. Poultry and minced or made-up meat deserve special care, because surface germs are worked all through them; they are cooked until done all the way, with no raw, cold, or bloody centre.

Reheating carries its own rule. Every spell in the danger zone between heatings is another chance for germs to multiply, and gentle reheating may warm food through the zone without reaching a killing heat. Where food genuinely must be reheated, it is reheated right through to properly hot, and once only. Better still, wherever it can be managed, cook only what will be eaten and avoid the cook-cool-reheat cycle.

Around the cooking, cleanliness must hold, or the cooked food is fouled before serving. Surfaces, boards, knives, pots, and utensils are kept clean. A board or knife used for raw meat is cleaned before it touches anything else, or a separate one is used, since the same board carried unwashed from raw meat to bread or salad takes disease straight across. Clean and dirty are kept apart as strictly as for water. The water used throughout must itself be safe, drawn from a treated, approved source as Lesson 02 teaches, because washing food or utensils in unsafe water simply moves contamination onto the meal.

The most important guard in the kitchen is the cook. A sick or unclean food-handler can poison a whole unit, and no later care undoes contamination from the hands that prepared the meal. A food-handler must therefore keep a high standard of personal hygiene. They wash the hands thoroughly with safe water and soap: before handling food, after the latrine, after raw meat, after touching the face, hair, or anything dirty, and whenever the hands may have picked up contamination. Clean hands are the single most important thing in the kitchen. They avoid double-handling, using clean utensils to serve rather than re-touching food with bare hands. And anyone unwell does not handle food at all. A stomach upset, vomiting or diarrhoea, a fever, or infected sores, septic cuts, or boils on the hands or arms means reporting sick and staying away from food until well and cleared, because that illness is exactly what would pass to everyone they cook for. This protects the unit, not burdens the cook.

Serving food

The last point at which a meal can be fouled is serving. Food is served cleanly, with clean utensils and clean hands, by people who are themselves clean and well; it is kept covered against flies and dust to the moment it is given out, and served promptly rather than left standing warm on the line. Everyone washes their hands before eating, so a hand-washing place belongs wherever food is served. Each person uses their own mess gear, washed clean, because a dirty mess tin is a sure way to bring on diarrhoea even when the food was sound.

Washing up properly

Washing up is part of food hygiene in its own right, because mess gear that is badly cleaned carries the last meal's contamination into the next. It follows a fixed order, and the order matters as much as the effort.

First, scrape the food scraps off into the rubbish, so they go to waste discipline (Lesson 04) and not into the wash water. Then wash in hot water with soap or detergent, scrubbing to lift grease and food, because grease left behind shelters germs. Then rinse in clean, hot water to carry away the soap and loosened filth. Then, wherever it can be managed, give a final hot or disinfecting rinse: water as hot as can be used, or a food-safe disinfectant made up to its instructions, to kill the germs washing has loosened but not destroyed. Finally, drain and air-dry on a clean rack, and do not wipe dry with a cloth, since a damp, dirty cloth spreads filth from one item to the next. A practical field arrangement holds this order as a line of containers: one to scrape into, one of hot soapy water, one of clean hot water, and a final hot or disinfecting rinse, then the gear set out to air-dry. The water must itself be safe, and is changed before it becomes a greasy soup that cleans nothing.

Rubbish and food-waste discipline

A kitchen makes waste: scraps, peelings, wash water, empty tins. That waste is exactly what draws the flies and rats that carry disease back to the food, so controlling it is part of cooking hygiene. Food scraps and rubbish are collected as they are made, kept in covered containers so flies cannot reach them and breed, and cleared away promptly rather than left to pile up between meals. Greasy wash water and food waste are disposed of well away from the kitchen and from any water source, so the kitchen fouls neither itself nor the water supply. The full method of disposing of rubbish, food waste, and greywater is the subject of Lesson 04; here, a clean kitchen keeps its own waste under firm control.

The standard of a field kitchen

A unit's freedom from food-borne disease is in large part the measure of how well its kitchen is run. The standard has a few plain parts.

First, it is sited well: well away from the latrines and from any waste or refuse, on the order of a hundred metres, and not on the slope or wind that would carry filth toward the food. Siting kitchen and latrines well apart is one of the first acts of a clean camp, taught again in the next lesson.

Second, it is kept scrupulously clean. Surfaces and equipment are cleaned before and after preparing food, the area kept free of dirt, food scraps, and standing water, and food prepared and served up off the ground and under cover. Doors and openings of a kitchen tent are kept closed or screened against flies wherever the means exist. A clean kitchen does not feed the flies and vermin that a dirty one attracts.

Third, its waste is controlled: scraps, wash-water, and rubbish disposed of properly and promptly, not left to pile up and draw pests, as the next lesson teaches.

Fourth, and above all, it is run by food-handlers held to a high standard of hygiene and health. Everything depends on the people: clean hands, clean habits, safe water, food kept out of the danger zone, and the firm rule that the sick and the unclean do not handle food. Hold the whole standard in mind as a chain, each link a discipline this lesson has taught, only as strong as its weakest link.

   THE FOOD-SAFETY CHAIN
   (the meal is safe only if EVERY link holds)

   [ CLEAN  ]--[ COOL  ]--[ HOT   ]--[ CLEAN ]--[ NO STANDING ]
   [ SOURCE ]  [ STORE ]  [ COOK  ]  [ HANDS ]  [ WARM        ]
       |           |          |          |            |
   only sound   keep cold  cook right  wash hands  serve and eat
   food in,     food cold, through,    with soap,  promptly; do
   inspected;   raw apart  reheat once clean tools not hold warm
   safe water   from cooked  only      and surfaces or cook ahead

   Break one link and the chain fails: the meal is shared,
   so one failure reaches everyone who eats.

A kitchen kept to this standard is the cheapest and surest medicine a unit has, and for the Army's humanitarian work it is more. A relief kitchen feeding a stricken, weakened population must be held to the same standard or higher, because an outbreak among people already brought low by disaster, the very young, the old, the sick, and the malnourished among them, can do terrible harm. This is care owed by need: the greater the vulnerability of those fed, the higher the standard owed them. That work is taught further in Caring for Those in Need and in the Aid to the Civil Power course; the standard it rests on is taught here.

In Practice: The Cook at the Relief Camp

At a welfare camp beside a flood-struck town, two cooks prepare the day's meals for displaced families, and the difference between them is the whole of this lesson. The first sites his cooking place hard by the makeshift latrines because it is convenient. He takes in fresh meat from a passing trader with no check on how it was kept, leaves it in the warm morning air while he sees to other things, and cooks a great pot of stew early, then lets it stand warm for hours. Flies move freely between the rubbish heap and the open food. He washes the mess gear in a tub of cold, grey, greasy water and wipes the tins with the same rag he has used all morning. He serves with hands he has not washed since he last went aside, and says nothing of the loose stomach he has had for two days. By evening, families across his end of the camp are falling ill, the children worst, and the relief meant to shelter them is making them sicker.

The second cook keeps her kitchen well away from the latrines and waste, on ground that does not drain toward the food. She takes in only rations and food she can trust, inspects the tins and turns back a bulging one, keeps the meat cold until it goes on the fire, and cooks it right through, close to the time it will be eaten. She keeps boards and knives clean and raw and cooked apart, covers the food against flies and dust, and uses only treated water to cook and to wash up. She washes the mess gear properly: scrape, hot wash, hot rinse, and out to air-dry on a clean rack, never the dirty cloth. She insists everyone, herself included, washes their hands before touching food, and when a helper reports a stomach upset she sends him from the food at once. No sickness comes from her kitchen. The flood was the same at both ends of the camp; the difference was the discipline of the cook.

Check Your Understanding

Describe the two paths by which food carries disease and the four routes of contamination, and explain what multiplication is and why it means food that looks and smells sound can still be dangerous. Why can food-borne illness disable a whole unit at once?
What is the danger zone, and what is meant by keeping cold food cold and hot food hot? Why is it dangerous both to hold cooked food warm for long and to cook far ahead, and what is the rule on reheating?
Why can a single sick or unclean food-handler poison a whole unit, and what standards of hygiene and health must a food-handler keep? Set out the proper order for washing up and say why air-drying rather than a cloth matters. What makes a field kitchen safe in its siting, cleanliness, waste, and the people who run it?

Reflection (write a short paragraph): This lesson argues that food safety is an unbroken chain of plain disciplines, and that one careless or unwell food-handler can make many people ill at a single shared meal. Think of a relief or field task where food is prepared for many. Which link in the chain, clean source, cool store, thorough cooking, clean hands, no standing warm, or proper washing-up, would be hardest to hold when tired, rushed, or short of safe water, and how might letting that one link slip open the food route of disease for everyone who eats, including the vulnerable people in the Army's care?

Summary

Food carries disease through food that is contaminated or spoiled and through unclean handling. The four routes are dirty hands, dirty water, pests, and spoilage; and multiplication, the breeding of germs in food left warm, turns a small fault into a dangerous dose, so food that looks and smells fine can still sicken a shared unit all at once.
Sourcing comes first: take in only sound food from a source you can trust, have locally bought food, drink, and ice approved before use, and inspect everything, sealed, in date, no bulging or damaged tins, no spoilage; when in doubt, throw it out.
Safe storage means keeping cold food cold and hot food hot and out of the danger zone between, protecting food from pests and dust, keeping raw apart from cooked, and never holding cooked food warm for long or cooking far ahead, since warmth lets germs multiply.
Safe cooking means cooking food thoroughly right through, especially meat, poultry, and fish; reheating once only and avoiding the cook-cool-reheat cycle; keeping surfaces and utensils clean and raw apart from ready-to-eat; using only safe water (Lesson 02); and above all the food-handler's own hygiene and health, clean hands, no double-handling, and no handling of food by anyone unwell.
Safe serving and washing-up mean clean serving with clean utensils, hand-washing before eating, and mess gear washed in order, scrape, hot wash, hot rinse, a hot or disinfecting rinse, then air-dry, never wiped with a dirty cloth. Food waste and rubbish are kept covered and cleared promptly to deny pests (Lesson 04).
A field kitchen is held to a strict standard: sited well away from latrines and waste, kept scrupulously clean, its waste controlled, and run by food-handlers held to a high standard of hygiene and health. The same standard, or higher, keeps a relief kitchen from harming the people it feeds, by the principle that care is owed by need.

Food and Cooking Hygiene