Safe Food PreparationHaumaru Kai

Care and attention must be paid when preparing food for public consumption, with at a cafe, restaurant, market or charity event. This is easy to do if you remember the 4 Cs - clean, cook, cover, chill.

Clean, Cook, Cover, Chill 

Clean

Wash and thoroughly dry your hands on a clean towel before handing food and after handling raw meat and poultry, using the bathroom, handling pets or being outside in the garden.

Wash knives and utensils, and scrub chopping boards between preparation of raw and cooked foods.

Cook

Food borne illnesses are caused by bacteria that multiply quickly in moist, warm conditions where there is a suitable food source. Handling food carefully can prevent the bacteria from getting to levels where they cause illness. Cooking food thoroughly helps kill the bacteria.

• Always defrost frozen foods in the fridge before cooking.
• Cool hot foods, covered, for no more than 30 minutes before refrigerating. 
• Reheat leftovers until steaming hot throughout and do not reheat them more than once.
• Chicken, meat patties and sausages need to be cooked thoroughly before serving. It's a good idea to pre-cook these meats before barbecuing.
• Do not put cooked meat back on the same plate that held raw meat. Ensure there are no traces of pink meat or juices before eating.

Cover

Cover foods before storing in the cupboard or fridge to prevent any bacteria from spreading. It is important to store raw and cooked foods separately, and a good idea to store raw meats at the bottom of the fridge to ensure juices don't drip onto other foods.

Chill

Bacteria causing food borne illnesses thrive at room temperatures, so keep food either very cold or very hot. A chilly bin keeps chilled products cold when taking them home from the supermarket, or you can put a frozen chilly pad with your picnic foods to keep food safe.

Remember to check the use by dates and if in doubt, throw it out!

Due to public demand for fast, fresh, heat-and-eat meal solutions that have fewer preservatives and additives, the incidence of food borne illness in New Zealand is a considerable threat. Fresh and fast food or ready to cook meals may be more convenient but ingredients must be looked after properly to keep them safe.

Food Safety

Some foods are harmful right from the start, such as poisonous mushrooms, rhubarb leaves and some berries. Some foods become harmful due to changes that occur in them, such as diseases or contamination with foreign substances, or contamination from unsafe or untreated water supplies.

Harmful food can result from:

• Bacteria can get into food via soils or water in plants, or via the skin or gut of an animal at slaughter. Depending on the type of bacteria, it may cause illness simply by being present, or it may produce toxins in the food or in the person who ate that food. Most of our food borne illnesses in New Zealand are caused by bacteria. 
• Fungi and moulds can also grow on many food types. Some are not harmful, but others can create toxins in food that are very poisonous. It is neither safe nor appropriate to sell or serve food that has become mouldy with fungus, unless it is supposed to be, such as blue cheeses.
• Viruses are becoming a more likely cause of food borne illness in New Zealand. They are most likely to get into food from water or unsafe food handling by someone who is ill. 
• Parasites such as gut worms, protozoa such as giardia and cryptosporidium, and other parasites are likely to get into food from contaminated water, from soil dust or from poor food handling by someone who is ill.
• Chemicals are most likely to get into food from cleaning agents, pest control agents, or as metals from improper storage in tins and such.
• Some poisons come from the foods themselves, such as decoration with poisonous garden plants. Some poisons are ingested by the food when alive and passed on to humans, such as when shellfish have eaten toxic algae and become poisonous themselves.

Food borne illness

There are many types of food borne illness, resulting from spoilage, contamination, infestation, bacterial load or toxins produced by bacteria or moulds.

Wholesomeness

Let's face it, if you're in the food business, you want to make money from selling your food. Your food needs to look good, taste good and attract customers. Food that doesn't look good may or may not be harmful, but it will certainly turn off your customers anyway.

Spoilage

Spoiled food is mainly due to chemical reactions involved in food ageing or decaying, and/or to bacteria. Drying, stalling, contamination and damage by pests can also spoil food.

Chemical food spoilage in food aging is caused by enzyme reactions natural to the living organism, continuing on after it has been slaughtered or harvested (e.g. fruit ripening once picked, continuing on to rot level). Initially these changes in meat make it more tender and flavoursome, but it continues on to 'sogginess' and putrefaction if not stored at the correct temperatures. The fat in meat can also become rancid through oxidation, causing what is commonly recognised as 'off' flavours in cooked meat. Fish is more susceptible and so requires much colder temperatures to delay the decaying process.

Microbial food spoilage may be due to either bacteria or moulds and yeast, with bacteria being the more harmful. Food spoilage is due to changes in the food caused by bacteria feeding on it, and their waste products. However, in many cases the spoiled food is not as harmful as the presence of the bacteria. Microbial contamination usually comes from damage to the food. In meat, this usually occurs at slaughter when natural bacterial infestation of the skin and intestines of the carcass contaminates the meat itself.

Spoilage isn't necessarily harmful but it might be, and you can't always tell.

Avoid food spoilage by eating food fresh, or refrigerating food then cooking it soon after purchase and eating it. Choose fruit and vegetables with clean, intact skins; meat that isn't slimy, green or smelly; and other foods free from mould or dust.

Contamination

There are three possible types of contamination to be avoided - physical, chemical and microbial. 

Physical contamination is when some foreign object is present that shouldn't be there. It could be harmful (such as a piece of glass) or just offensive (such as a freshly washed slug on salad). Many foreign object contaminations can be both harmful and offensive, such as hairs/fingernails or dead insects. It doesn't matter. If it looks like it shouldn't be there, it will offend your customers and you could be liable for an offence against the Food Hygiene Regulations or the Food Act 2014.

Be aware that even something harmless but offensive can make people ill, and be terrible for your reputation as a food provider.

Chemical contamination usually comes from inappropriate storage of cleaning solutions and pest control poisons. Make sure any non-food items are stored in a marked container so that they cannot be mistaken for anything else. They must be stored somewhere away from food items so that any possible leakage does not contaminate any food items.

Microbial contamination is the most common form of contamination and the most potentially harmful. Contamination could result from bacteria, viruses, yeasts and moulds, or other microscopic 'bugs'. Some foods will be naturally laden with bacteria, such as raw meats, but most foods get their microbial contamination from the food handler, pests or cross-contamination from other food handling items (e.g. knives, cutting boards and slicers). 

Illness resulting from excessive bacterial growth can be one of two types:

1. Food infection is caused by the presence of the bacteria, usually due to multiplication of the bacteria to large numbers over time. Illness may not occur until some time after consumption of the contaminated food and symptoms of the illness will be specific to those bacteria.
2. Food poisoning is caused by toxins released from the bacteria. It is likely to be more severe and develop quickly. Prevention of bacterial contamination and control of growth are essential because some of these toxins are resistant to average cooking temperatures.

Moulds may also cause food spoilage but still be desirable and harmless to eat, such as in blue cheeses. Meats, breads and sweet foods are also likely to be attacked by moulds. These are not generally harmful but like bacteria, moulds can release toxins so it is best not to eat them.

In New Zealand, bacteria is the biggest cause of making food unsafe to eat. If you prevent the presence and/or control the harm from bacteria, you will likely control the other potentially harmful sources. 

High and Low-Risk Foods

Different foods carry different risks of becoming harmful to eat depending on factors such as water content, sugar levels, acidity, salt content, protein levels, natural bacterial load, exposure to air, and how we prepare and eat them. Foods may be considered to be stable, semi-perishable, perishable, raw or cooked.

For example, toast is more stable than bread because the lower moisture content doesn't support mould and bacterial growth as well. Similarly, raw meat will rot faster than cooked meat; however, cooked meat is more risky as it is likely to be eaten as it is, whereas raw meat is likely to be cooked and rendered safe. You must consider foods that are ready to be eaten as higher risk.

High-risk foods include:

• Cooked meat and poultry
• Cooked meat products such as pies, gravy, sauces, soups and stocks
• Processed meat products
• Some meat cuts eaten raw or rare
• Shellfish
• Milk, cream, custards and other dairy products
• Cooked rice
• Eggs (especially raw), egg products, custards and mayonnaise

These foods are readily perishable due to being excellent food sources for bacteria and therefore prone to spoilage and infection. Many of the bacteria associated with these foods are also toxin producing, leading to food poisoning.

Lower-risk foods include:

• Jams and chutneys
• Pickled foods
• Foods preserved in brine (salt)
• Dry foods, such as flour and grains
• Foods preserved in alcohol or oil

These foods are low risk because bacteria need a warm (room temperature), moist environment to survive in that provides some food source. Bacteria cannot live in any food that is high in sugar, acid, salt, alcohol or oil.

Some bacteria need oxygen and some mustn't have it, so it is difficult to use air supply as a control tool for food safety.

Food preservation by drying, salting and smoking, sweetening and acidifying provides environments that bacteria cannot survive in. These methods must be done properly to avoid toxin production. Preservation by heating (as in canning and pasteurisation) kills off the harmful bacteria. Sealing to prevent re-contamination is essential.