This time of year, most fridges are stocked up with food and drinks to share with family and friends. Let’s not make ourselves and our guests sick by getting things wrong when preparing and serving food.

As the weather warms up, so does the environment for micro-organisms in foods, potentially allowing them to multiply faster to hazardous levels. So put the drinks on ice and keep the fridge for the food.

But what are some of those food safety myths we’ve long come to believe that aren’t actually true?

Myth 1: if you’ve defrosted frozen meat or chicken you can’t refreeze it

From a safety point of view, it is fine to refreeze defrosted meat or chicken or any frozen food as long as it was defrosted in a fridge running at 5°C or below. Some quality may be lost by defrosting then refreezing foods as the cells break down a little and the food can become slightly watery.

Another option is to cook the defrosted food and then divide into small portions and refreeze once it has stopped steaming. Steam in a closed container leads to condensation, which can result in pools of water forming. This, combined with the nutrients in the food, creates the perfect environment for microbial growth. So it’s always best to wait about 30 minutes before refrigerating or freezing hot food.

Plan ahead so food can be defrosted in the fridge, especially with large items such as a frozen turkey or roll of meat. If left on the bench, the external surface could be at room temperature and micro-organisms could be growing rapidly while the centre of the piece is still frozen!

Myth 2: Wash meat before you prepare and/or cook it

It is not a good idea to wash meats and poultry when preparing for cooking. Splashing water that might contain potentially hazardous bacteria around the kitchen can create more of a hazard if those bacteria are splashed onto ready-to-eat foods or food preparation surfaces.

It is, however, a good idea to wash fruits and vegetables before preparing and serving, especially if they’re grown near or in the ground as they may carry some dirt and therefore micro-organisms.

This applies particularly to foods that will be prepared and eaten without further cooking. Consuming foods raw that traditionally have been eaten cooked or otherwise processed to kill pathogenic micro-organisms (potentially deadly to humans) might increase the risk of food poisoning.

Fruit, salad, vegetables and other ready-to-eat foods should be prepared separately, away from raw meat, chicken, seafood and other foods that need cooking.

Myth 3: Hot food should be left out to cool completely before putting it in the fridge

It’s not OK to leave perishable food out for an extended time or overnight before putting it in the fridge.

Micro-organisms can grow rapidly in food at temperatures between 5° and 60°C. Temperature control is the simplest and most effective way of controlling the growth of bacteria. Perishable food should spend as little time as possible in the 5-60°C danger zone. If food is left in the danger zone, be aware it is potentially unsafe to eat.

Hot leftovers, and any other leftovers for that matter, should go into the fridge once they have stopped steaming to reduce condensation, within about 30 minutes.

Large portions of hot food will cool faster if broken down into smaller amounts in shallow containers. It is possible that hot food such as stews or soup left in a bulky container, say a two-litre mixing bowl (versus a shallow tray), in the fridge can take nearly 24 hours to cool to the safe zone of less than 5°C.

Myth 4: If it smells OK, then it’s OK to eat

This is definitely not always true. Spoilage bacteria, yeasts and moulds are the usual culprits for making food smell off or go slimy and these may not make you sick, although it is always advisable not to consume spoiled food.

Pathogenic bacteria can grow in food and not cause any obvious changes to the food, so the best option is to inhibit pathogen growth by refrigerating foods.

Myth 5: Oil preserves food so it can be left at room temperature

Adding oil to foods will not necessarily kill bugs lurking in your food. The opposite is true for many products in oil if anaerobic micro-organisms, such as Clostridium botulinum (botulism), are present in the food. A lack of oxygen provides perfect conditions for their growth.

Outbreaks of botulism arising from consumption of vegetables in oil – including garlic, olives, mushrooms, beans and hot peppers – have mostly been attributed to the products not being properly prepared.

Vegetables in oil can be made safely. In 1991, Australian regulations stipulated that this class of product (vegetables in oil) can be safely made if the pH (a measure of acid) is less than 4.6. Foods with a pH below 4.6 do not in general support the growth of food-poisoning bacteria including botulism.

So keep food out of the danger zone to reduce your guests’ risk of getting food poisoning this summer. Check out other food safety tips and resources from CSIRO and the Food Safety Information Council, including testing your food safety knowledge.

Cathy Moir, Team leader, Microbial and chemical sciences, Food microbiologist and food safety specialist, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Cannabis, cocaine and heroin have interesting life stories and long rap sheets. We might know them today as illicit drugs, but each was once legal.

Then things changed. Racism and politics played a part in how we viewed them. We also learned more about their impact on health. Over time, they were declared illegal.

But decades later, these drugs and their derivatives are being used legally, for medical purposes.

Here’s how we ended up outlawing cannabis, cocaine and heroin, and what happened next.

Cannabis, religion and racism

Cannabis plants originated in central Asia, spread to North Africa, and then to the Americas. People grew cannabis for its hemp fibre, used to make ropes and sacks. But it also had other properties. Like many other ancient medical discoveries, it all started with religion.

Cannabis is mentioned in the Hindu texts known as the Vedas (1700-1100 BCE) as a sacred, feel-good plant. Cannabis or bhang is still used ritually in India today during festivals such as Shivratri and Holi.

From the late 1700s, the British in India started taxing cannabis products. They also noticed a high rate of “Indian hemp insanity” – including what we’d now recognise as psychosis – in the colony. By the late 1800s, a British government investigation found only heavy cannabis use seemed to affect people’s mental health.

In the 1880s, cannabis was used therapeutically in the United States to treat tetanus, migraine and “insane delirium”. But not everyone agreed on (or even knew) the best dose. Local producers simply mixed up what they had into a tincture – soaking cannabis leaves and buds in alcohol to extract essential oils – and hoped for the best.

So how did cannabis go from a slightly useless legal drug to a social menace?

Some of it was from genuine health concerns about what was added to people’s food, drink and medicine.

In 1908 in Australia, New South Wales listed cannabis as an ingredient that could “adulterate” food and drink (along with opium, cocaine and chloroform). To sell the product legally, you had to tell the customers it contained cannabis.

Some of it was international politics. Moves to control cannabis use began in 1912 with the world’s first treaty against drug trafficking. The US and Italy both wanted cannabis included, but this didn’t happen until until 1925.

Some of it was racism. The word marihuana is Spanish for cannabis (later Anglicised to marijuana) and the drug became associated with poor migrants. In 1915, El Paso, Texas, on the Mexican border, was the first US municipality to ban the non-medical cannabis trade.

By the late 1930s, cannabis was firmly entrenched as a public menace and drug laws had been introduced across much of the US, Europe and (less quickly) Australia to prohibit its use. Cannabis was now a “poison” regulated alongside cocaine and opiates.

The 1936 movie Reefer Madness was a high point of cannabis paranoia. Cannabis smoking was also part of other “suspect” new subcultures such as Black jazz, the 1950s Beatnik movement and US service personnel returning from Vietnam.

Today recreational cannabis use is associated with physical and mental harm. In the short term, it impairs your functioning, including your ability to learn, drive and pay attention. In the long term, harms include increasing the risk of psychosis.

But what about cannabis as a medicine? Since the 1980s there has been a change in mood towards experimenting with cannabis as a therapeutic drug. Medicinal cannabis products are those that contain cannabidiol (CBD) or tetrahydrocannabinol (THC). Today in Australia and some other countries, these can be prescribed by certain doctors to treat conditions when other medicines do not work.

Medicinal cannabis has been touted as a treatment for some chronic conditions such as cancer pain and multiple sclerosis. But it’s not clear yet whether it’s effective for the range of chronic diseases it’s prescribed for. However, it does seem to improve the quality of life for people with some serious or terminal illnesses who are using other prescription drugs.

Cocaine, tonics and addiction

Several different species of the coca plant grow across Bolivia, Peru and Colombia. For centuries, local people chewed coca leaves or made them into a mildly stimulant tea. Coca and ayahuasca (a plant-based psychedelic) were also possibly used to sedate people before Inca human sacrifice.

In 1860, German scientist Albert Niemann (1834-1861) isolated the alkaloid we now call “cocaine” from coca leaves. Niemann noticed that applying it to the tongue made it feel numb.

But because effective anaesthetics such as ether and nitrous oxide had already been discovered, cocaine was mostly used instead in tonics and patent medicines.

Perhaps the most famous example was Coca-Cola, which contained cocaine when it was launched in 1886. But cocaine was used earlier, in 1860s Italy, in a drink called Vin Mariani – Pope Leo XIII was a fan.

With cocaine-based products easily available, it quickly became a drug of addiction.

Cocaine remained popular in the entertainment industry. Fictional detective Sherlock Holmes injected it, American actor Tallulah Bankhead swore by it, and novelist Agatha Christie used cocaine to kill off some of her characters.

In 1914, cocaine possession was made illegal in the US. After the hippy era of the 1960s and 1970s, cocaine became the “it” drug of the yuppie 1980s. “Crack” cocaine also destroyed mostly Black American urban communities.

Cocaine use is now associated with physical and mental harms. In the short and long term, it can cause problems with your heart and blood pressure and cause organ damage. At its worst, it can kill you. Right now, illegal cocaine production and use is also surging across the globe.

But cocaine was always legal for medical and surgical use, most commonly in the form of cocaine hydrochloride. As well as acting as a painkiller, it’s a vasoconstrictor – it tightens blood vessels and reduces bleeding. So it’s still used in some types of surgery.

Heroin, coughing and overdoses

Opium has been used for pain relief ever since people worked out how to harvest the sap of the opium poppy. By the 19th century, addictive and potentially lethal opium-based products such as laudanum were widely available across the United Kingdom, Europe and the US. Opium addiction was also a real problem.

Because of this, scientists were looking for safe and effective alternatives for pain relief and to help people cure their addictions.

In 1874, English chemist Charles Romley Alder Wright (1844-1894) created diacetylmorphine (also known as diamorphine). Drug firm Bayer thought it might be useful in cough medicines, gave it the brand name Heroin and put it on the market in 1898. It made chest infections worse.

Although diamorphine was created with good intentions, this opiate was highly addictive. Shortly after it came on the market, it became clear that it was every bit as addictive as other opiates. This coincided with international moves to shut down the trade in non-medical opiates due to their devastating effect on China and other Asian countries.

Like cannabis, heroin quickly developed radical chic. The mafia trafficked into the US and it became popular in the Harlem jazz scene, beatniks embraced it and US servicemen came back from Vietnam addicted to it. Heroin also helped kill US singers Janis Joplin and Jim Morrison.

Today, we know heroin use and addiction contributes to a range of physical and mental health problems, as well as death from overdose.

However, heroin-related harm is now being outpaced by powerful synthetic opioids such as oxycodone, fentanyl, and the nitazene group of drugs. In Australia, there were more deaths and hospital admissions from prescription opiate overdoses than from heroin overdoses.

In a nutshell

Not all medicines have a squeaky-clean history. And not all illicit drugs have always been illegal.

Drugs’ legal status and how they’re used are shaped by factors such as politics, racism and social norms of the day, as well as their impact on health.

Philippa Martyr, Lecturer, Pharmacology, Women’s Health, School of Biomedical Sciences, The University of Western Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.