Have you ever wondered why paraffin wax is used in certain food items such as cheese? If you did, it would not very surprising. Besides, it looks like the substance used for making candles, right? Who would dare to eat candles? Kidding aside, paraffin wax has long been used in food as a very effective packaging since the late 19th century.

It was first discovered in the 1830s by German chemist Karl von Reichenbach. Decades later, its use expanded to various industries, including food manufacturing. As you might already think, paraffin wax has been used as a food packaging materials for over a century now, and there is not a problem.

So to answer your question—is paraffin wax in food toxic?

No, paraffin wax used in food is not a toxic substance, and its food-grade—it has been processed, refined, and purified.

Let’s discuss further.

WHAT IS PARAFFIN WAX?

Chemistry

Paraffin wax is a soft, crystalline white or colorless petroleum product. It is solid at room temperature between 136°F (58°C)- 144 (62°C). As a byproduct, it is composed of hydrocarbons that form during the refining process of crude oil. Going back to basic chemistry, hydrocarbons are compounds that consist of hydrogen and carbon entirely. There are 4 classes of it: alkanes, alkenes, alkynes and arenes. Paraffin wax consists mostly of alkanes, the kind of saturated hydrocarbon wherein the hydrogen atoms are connected by a single bond between carbon atoms.

However, the actual composition of the wax depends on many factors, including the refining method and the crude oil itself. In many cases, the paraffin wax may contain traces of other hydrocarbons, including alkenes or alkynes.

In food

As I have already mentioned, paraffin wax was first made not for packaging food items—but as an aid for separating wax substance found in petroleum. It found its first main purpose in making candles. Before the discovery of paraffin wax, candle makers used tallow fat. However, the flame made from it is smoky and emits unpleasant odor.

The discovery of paraffin wax as an ideal material for making candles was a breakthrough. It creates a cleaner and brighter flame, and it is an inexpensive alternative to tallow fat.

By the early 20th century, some food items have started to be shipped out in paraffin wax. Examples of these foods, include candies, chocolates, cheese, and fruits.

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And these are for good reasons. Paraffin wax possesses moisture and oxygen-barrier properties. Moisture and oxygen are external factors that negatively affect the shelf life and quality of food. Certain types of cheeses, for example, require ample amount of moisture to retain its flavor, appearance, and texture for an extended period of time. Gouda, Cheddar, and Queso de Bola (Philippine cheese) often come enclosed in red paraffin wax.

IS PARAFFIN WAX SAFE TO EAT? IS IT TOXIC?

No, paraffin wax safe is not there for consumption. It is a no-brainer. It is just a packaging to protect the food inside. And if you did digest a small amount, it would not cause harm because it would just exit your body unchanged. A considerably amount of it is a different story though. It may result in discomfort in your digestive system.

The most apparent concern here is if paraffin wax in food is toxic. Besides, it is a food contact surface. Since I have already answered this question earlier, I will just explain why it is not a toxic substance.

Paraffin wax is a chemically inert substance—it does not react with other substances, food, in particular.

And here is why (more chemistry alert).

As we have already discussed, paraffin wax is composed mostly of (alkanes) saturated hydrocarbons. In this arrangement, the carbon atoms are bonded totally with the hydrogen atoms. For this reason, it is not possible for double or even triple bonds to form. To simply put, alkanes are unreactive type of hydrocarbons.

Furthermore, there are also no functional groups such as carboxyl and hydroxyl groups. These functional groups can readily react with other substances. because of the absence of these functional groups, there are no chances for other atoms within a molecule to interact with.

Well, paraffin wax will start a reaction if you light it up with food still inside it. But you would not do that, of course. Paraffin wax has a high energy activation requirement in order for the stable carbon-hydrogen bonds to break and form new ones.

So that is it. Paraffin wax is not a toxic substance in food.

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Silica gel packets are those small pouches often found in food, medicine, and other packaging. The common warning “Do not eat” has led many to wonder about their safety and potential toxicity. Given how often these packets appear in everyday products, it’s understandable that people have questions.

In this blog post, we will discuss what silica gel is, how it functions, its various applications, and whether it poses any health risks.

What Is Silica Gel?

Silica gel is an example of a desiccant. Desiccants are substances that have the capability to absorb and retain moisture. In many industries, silica gel is often used. It is made of silicon dioxide (SiO₂), the same compound found in quartz and sand. Its porous structure allows it to absorb water molecules from the surrounding environment. 

For this reason, it is very effective in keeping the humidity within the packaging at desirable levels. This is especially useful in preserving the quality and shelf life of various products. 

Typically, silica gel comes in the form of tiny, spherical beads or granules. These beads have a vast surface area, filled with microscopic pores that attract and trap moisture. When exposed to humid conditions, the moisture is drawn into these pores and held there by molecular forces. Because of this, there is a reduction in humidity within a sealed environment.

One of the key benefits of silica gel is that it can be regenerated and reused. After the gel becomes saturated with moisture, it can be dried out by heating it to around 392°F (200°C), a process that drives off the absorbed water and restores its moisture-absorbing properties. This makes silica gel not only effective but also sustainable for repeated use in various applications.

How Is Silica Gel Used in Food and Medicine?

Silica gel’s moisture-absorbing properties make it indispensable in several industries, particularly food and pharmaceuticals.

In food packaging, silica gel packets maintains the product quality by controlling moisture levels. Many dry foods, such as snacks, nuts, and dehydrated goods, are highly susceptible to moisture. The moisture can lead to spoilage, mold growth, and changes in texture and flavor. By absorbing excess moisture, silica gel packets help keep these products fresh and crunchy, extending their shelf life and ensuring they remain safe to consume.

For example, consider a bag of potato chips. If moisture enters the packaging, the chips can become soggy and lose their crispness. Silica gel packets prevent this by maintaining a dry environment inside the package, preserving the product’s texture and taste. Similarly, in the case of powdered or granulated foods like spices and coffee, silica gel prevents clumping and caking, ensuring that these products retain their intended consistency and flavor.

In the pharmaceutical industry, silica gel is commonly included in the packaging of pills, capsules, and vitamins. Medications are often sensitive to moisture, which can lead to chemical degradation, reducing their potency and effectiveness. For instance, vitamins and supplements can lose their efficacy when exposed to humidity, while tablets can become sticky and clump together, making them difficult to dose accurately.

Common Uses of Silica Gel in Packaging:

Are Silica Gel Packets Toxic?

Silica gel packets often are packed in packaging that says, “Do Not Eat”. But silica gel is non-toxic and chemically inert, meaning it doesn’t react with other substances and poses no health risk when handled properly. In fact, silica gel is sometimes used as a lubricating agent in certain drug formulations, underscoring its safety in small quantities.

The warning on the packet is primarily about safety rather than toxicity. The small beads can pose a choking hazard, particularly for young children and pets. This is why ingestion should be avoided. However, if accidentally swallowed, silica gel typically passes through the digestive system without causing harm. A study found that silica gel ingestion accounts for 2.1% of annual poison control calls. But most cases result in no significant health issues, with only mild discomfort in some instances.

In certain cases, silica gel packets contain a moisture indicator, such as cobalt chloride. This indicator changes color when it absorbs moisture. This feature is useful for monitoring humidity levels, as it signals when the silica gel has reached its capacity and needs replacement. However, cobalt chloride can be harmful if ingested in large amounts. So it is important to keep these packets out of reach of children and pets.

The presence of cobalt chloride does not diminish the silica gel’s effectiveness in protecting products, but it does introduce a potential risk. Therefore, it’s essential to handle these packets with care and store them in a safe place.

If a silica gel packet is accidentally ingested, it’s advisable to seek medical advice, particularly if cobalt chloride is involved. However, most cases result in minimal to no harm, and simple precautions can prevent any issues.

Conclusion

So, are silica gel packets toxic? The answer is generally no—silica gel packets are non-toxic and safe when used correctly. While the warning labels might seem alarming, these packets are generally safe when used and handled correctly. By storing products containing silica gel out of reach of children and pets, you can ensure they continue to serve their purpose without posing any risk to your household.

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Powdered milk, alternatively referred to as dry milk or milk powder, is a dairy product obtained from liquid milk using a dehydration method. The liquid milk undergoes evaporation to eliminate a substantial portion of its water content. Subsequently, the concentrated liquid is converted into a dry, powdery state, often through techniques such as spray drying. The product is milk powder that serves as a convenient substitute for liquid milk, offering an extended shelf life and facilitating effortless storage and transport.

But, how enduring is this liquid milk alternative, really? Well, knowing powdered milk’ extended shelf life involves going beyond the surface of the “best-by” date.

HOW IS POWDERED MILK MADE

The production of milk powder involves a series of carefully controlled processes to transform liquid milk into a dry, shelf-stable form.

Initially, the primary ingredient—fresh liquid milk—undergoes a procedure referred to as evaporation. During this stage, the milk undergoes heating to eliminate a substantial portion of its water content. The objective is to condense the milk, increasing its density before advancing to the subsequent phase. This evaporation process, not only diminishes the volume for more convenient transportation, but also acts as the preliminary stage in eliminating moisture, a crucial element in preserving the integrity of the powder.

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/After evaporation, the concentrated milk is exposed to a process called spray drying. This is the pivotal step in converting liquid milk into a fine powder. The concentrated liquid is atomized into tiny droplets, which are then introduced into a hot air chamber. As the droplets travel through this chamber, the remaining water content evaporates, leaving behind small, dry particles of milk. The result is a powdery substance with a much longer shelf life compared to its liquid counterpart.

The last stage encompasses the packaging of the powdered milk in a manner that safeguards it against external factors, including moisture and light, ensuring sustained quality. Commonly, airtight containers or sealed pouches are employed to thwart moisture absorption and shield the powder from potential impurities. This packaging serves a pivotal role in maintaining both the flavor and nutritional content of the milk powder.

THE SHELF LIFE OF POWDERED MILK

Manufacturers put “best-by” dates on powdered milk. However, these are not hard and fast deadlines for spoilage. Instead, they indicate peak quality – the point where flavor and nutrient content might start to decline. The good news is, powdered milk boasts inherent resilience thanks to its dehydration process. This removes moisture, a key ingredient for bacterial growth, essentially putting the milk in a state of suspended animation.

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The duration powdered milk remains fit for consumption depends on factors like storage conditions, packaging, and the specific type of powdered milk. Typically, unopened powdered milk stored in a cool, dry environment can maintain its quality for up to two years or even more beyond the indicated “best by” date. Conversely, opened powdered milk has a comparatively shorter shelf life, and it is advisable to consume it within a few weeks to ensure optimal quality.

Nonfat dry milk (NFDM) boasts a lengthy shelf life when contrasted with whole dry milk. This is because of the extraction of fat content. The removal of fat acts as a deterrent to common factors like oxidation and rancidity. These chemical changes typically lead to the deterioration of food products. When stored unopened in a cool, dry location and within an airtight container, NFDM can endure for up to 25 years or even more. However, once the NFDM container is opened, its shelf life is diminished to approximately three months, according to Utah State University.

IS IT EXPIRED?

While powdered milk generally has a longer shelf life compared to liquid milk, various factors can contribute to its deterioration over time.

One of the most apparent signs of spoilage is a noticeable change in odor. Fresh and properly stored milk powder should have a mild, slightly sweet aroma. If the powder emits a sour, or rancid smell, it is likely an indication that the product has gone bad. The development of undesirable odors suggests the presence of spoilage microorganisms or the breakdown of fats within the powder.

Any deviation from the typical color, which is usually a creamy white, may indicate spoilage. Discoloration can manifest as yellowing or the presence of unusual dark spots. Such changes may be attributed to oxidation or the introduction of contaminants. A thorough visual inspection before use can help identify any potential issues with the milk powder.

Milk powder is intended to have a fine, powdery texture. The development of clumps or a change in texture, such as a gritty or lumpy consistency, suggests moisture infiltration. Clumping is a clear sign that the powder has absorbed water, leading to the formation of solidified clusters. Moisture not only compromises the quality of the milk powder, but also creates an environment conducive to the growth of microorganisms.

While milk powder may exhibit a slightly bland flavor due to the dehydration process, any noticeable off taste is an alarming signal of spoilage. An unpleasant or sour taste can result from the breakdown of fats and proteins within the powder. Performing a small taste test by mixing a small amount of powder with water can help discern any abnormal flavors.

The post How Long Does Powdered Milk Really Last? appeared first on The Food Untold.

Salmonella is a type of bacteria that can cause foodborne illnesses in humans. There are various strains of Salmonella. Among these, Salmonella enterica is one of the most common species that can infect people. It is responsible for the many cases of food poisoning each year, with symptoms ranging from mild gastrointestinal discomfort to severe illness. According to the Centers for Disease Control and Prevention (CDC), Salmonella cause about 1 million cases of foodborne illness every year. The bacteria can contaminate a wide range of foods, especially raw or undercooked foods such as meat, egg, and poultry.

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With the wide range of foods that salmonella can contaminate, you might ask if cooking can kill the bacteria. In this blog, we will explore the role of cooking in killing Salmonella and preventing foodborne infections.

WHAT IS SALMONELLA?

Salmonella, a Gram-negative bacterium, presents rod-shaped cells with lengths ranging from 2 to 5 micrometers when viewed under a microscope. These cells are non-sporulating, meaning they do not form spores, and they are motile, equipped with flagella that enable them to move.

Salmonella exhibits adaptability in its growth conditions. It is a facultative anaerobe, capable of thriving in both oxygen-rich and oxygen-poor environments. Its optimal growth temperature falls within the range 98°F (37°C) to 107.6°F (42°C), mirroring human body temperature. This characteristic is significant as it enables Salmonella to colonize the human gastrointestinal tract effectively. The optimal pH for Salmonella is between 6.5 to 7.5. The bacteria can also withstand low pH levels of around 4.5. This enables them to survive the acidic conditions of the stomach.

Moreover, Salmonella exhibits relative heat resistance, which raises concerns for food safety.

From a pathogenic standpoint, certain Salmonella strains are known to be harmful to humans and animals, causing diseases such as salmonellosis, typhoid fever, and gastroenteritis. These pathogenic strains possess virulence factors that facilitate host cell invasion and disease progression, including fimbriae, flagella, and type III secretion systems.

Transmission of Salmonella primarily occurs through the ingestion of contaminated food and water. Many food items, particularly those of animal origin, such as poultry, eggs, and meat, can serve as reservoirs for Salmonella. Fecal-oral transmission may transpire when food is mishandled, or when contaminated hands or surfaces come into contact with food.

Symptoms of Salmonella infection

Salmonellosis, an infection caused by the Salmonella bacterium, can be contracted by individuals when they consume food that has been contaminated, including inadequately cooked eggs, meats, poultry, or unpasteurized milk.

The symptoms of salmonellosis usually develop within 12-14 hours of eating the contaminated food, but can range from a few hours to several days.

Symptoms include nausea, vomiting, abdominal pain, headache, chills, diarrhea, prostration, muscular weakness, faintness, fever, restlessness, and drowsiness. These Symptoms typically last for 2-3 days.

The mortality rate for Salmonella food poisoning is 4.1%, but varies depending on age. The mortality rate is highest in infants (5.8%), followed by people over 50 years old (15%).

Up to 5% of people who recover from Salmonella food poisoning become carriers of the bacteria. This means that they can carry the bacteria in their intestines without showing any symptoms, but they can still spread the bacteria to others.

Now, back to the question.

CAN SALMONELLA BE KILLED BY COOKING?

Yes, Salmonella can be effectively killed by cooking when the correct temperatures are reached and maintained. According to a study, exposure to a temperature of 140°F (60°C) to 149°F (65°) for several minutes is sufficient to destroy salmonella bacteria.

The process of killing Salmonella through cooking relies on the application of heat. When food reaches these recommended temperatures and is held at them for a sufficient duration, the heat effectively breaks down the Salmonella bacteria’s cell walls and denatures the proteins within the cells. This process destroys the bacteria’s ability to cause infections, making the food safe to eat.

When preparing food, especially those susceptible to Salmonella contamination, cook it to the recommended temperature. For example, when cooking poultry, such as chicken and turkey, ensure it reaches a minimum internal temperature of 165°F (73.9°C). For ground meats like beef, pork, or lamb, aim for a temperature of 160°F (71.1°C). When cooking eggs, make sure both the egg white and yolk have solidified. Seafood should be heated to 145°F (62.8°C) or until it easily flakes apart with a fork. When reheating leftovers, be certain they reach a temperature of 165°F (73.9°C) to eliminate any potentially harmful bacteria that may have multiplied during storage.

References:

G. Cooper (2018). Food Microbiology. Library Press.

J. Jay, M. Loessner, D. Golden (2005). Modern Food Microbiology (7th edition). Springer.

Y. Motarjemi (2014). Encyclopedia of Food Safety. Academic Press.

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Eggs are a versatile and nutritious ingredient for many dishes because of its various functional properties. However, like any perishable food item, eggs have a limited shelf life. This is where the expiry date for eggs becomes crucial. Understanding the significance of expiry dates ensures that you can safely enjoy eggs while maintaining their quality. In this article, we will discuss the importance of expiry dates for eggs and some tests that can determine their freshness.

EXPIRY DATE FOR EGGS

The expiry date for eggs serves as a helpful guideline for consumers, providing an estimated timeframe during which eggs are expected to remain fresh and safe to consume. Generally, the expiration date is set at around 3 to 5 weeks after the eggs were packed, and it is typically printed on the carton, often preceded by the labels “EXP” or “Expiry Date.” The Food and Drug Administration (FDA) advises consuming eggs within 3 weeks for the best quality. However, it’s important to note that the expiry date is not an exact science, and eggs can often remain safe to eat for a few weeks beyond the stated expiration date.

The freshness and safety of eggs can be influenced by various factors, including the handling and storage conditions both before and after purchase. Proper storage practices are crucial in maintaining the quality and safety of eggs. Refrigeration is essential as it helps slow down the growth of bacteria. It is recommended to store eggs in their original carton, which provides protection against absorbing odors and moisture from the refrigerator. This helps preserve their quality and reduces the risk of contamination.

It’s worth mentioning that the expiration date primarily focuses on maintaining the optimum quality and taste of the eggs. Hence, the changes do not necessarily indicate that the eggs are unsafe to eat.

As eggs age, their quality may gradually decline. The proteins in the egg whites break down, causing them to become more liquid and less viscous. This can result in slightly runnier egg whites when cooked. Additionally, the yolks may lose some of their richness and color intensity, affecting the overall appearance of dishes like sunny-side-up eggs or custards.

TELLING THE FRESHNESS OF EGGS

Now how do you confirm the freshness and extent of changes? Well, there are several proven tests that you can do.

Water/float test

The water test provides a simple and dependable method to determine the freshness of an egg. By filling a glass or bowl with cold water and gently placing the egg inside, you can easily evaluate its freshness. Here’s how the water test is conducted:

If the egg sinks to the bottom of the container and rests horizontally, it is considered very fresh. This indicates a minimal air pocket, signifying that the egg is in optimal condition for consumption. A fresh egg typically contains a relatively small air pocket inside the shell. As eggs age, the egg white gradually loses moisture, leading to an expansion of the air pocket.

If the egg stands on one end at the bottom of the water, it is still suitable for consumption but not as fresh as an egg that sinks flat. This suggests a slight enlargement of the air pocket over time, indicating a less fresh egg.

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On the other hand, if the egg floats to the surface of the water, it is no longer fresh and should not be consumed. This indicates that the air pocket has significantly expanded, signifying an older egg.

The water test works because the behavior of the egg in water directly correlates with the size of the air pocket inside the shell.

Crack test

The crack test is a simple yet effective way to assess the freshness of an egg by examining the characteristics of the egg white and yolk.

When you crack open a fresh egg, you will notice that the egg white is thick and clear. It holds its shape well and doesn’t spread out too much in the bowl or plate. The yolk is round and firm, maintaining its distinct shape. These qualities indicate a fresh egg with optimal quality.

On the other hand, If the egg white appears watery and lacks thickness or if it spreads out excessively in the bowl or plate, it suggests that the egg is not fresh.

Similarly, the yolk of a fresh egg is round and firm, holding its shape. However, as the egg ages, the yolk may start losing moisture and become flatter. In some cases, the yolk may also develop discoloration, indicating a less fresh or even spoiled egg.

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When it comes to meal planning and leftovers, knowing how long you can safely store cooked rice in the fridge is essential. Rice is a staple in many cuisines and a versatile ingredient, but improper storage can lead to foodborne illnesses. So, how long can you keep cooked rice in the fridge before it goes bad?

THE SHELF LIFE OF COOKED RICE

Cooked rice, unlike its uncooked counterpart, has a limited shelf life due to its moisture content and the potential growth of harmful bacteria. As a general guideline, cooked rice can be safely stored in the refrigerator for about 4 to 6 days. Beyond this time frame, the risk of bacterial growth increases significantly, raising concerns about food safety.

Ideally, you should only keep rice in the fridge for 1 day. Reheating rice that is one day old is considered safe from a microbial standpoint, provided it has been stored properly in the refrigerator. Within the first day of refrigeration, the growth of harmful bacteria on cooked rice is typically limited, and reheating it thoroughly can help kill any remaining bacteria.

The recommended shelf life of cooked rice in the refrigerator may vary depending on the type of rice and any added ingredients. For instance, if the cooked rice includes meat, seafood, or other perishable components, it is best to consume it within 2 to 3 days. It is also important to consult manufacturer guidelines or trusted recipe sources for specific storage recommendations to ensure the best shelf life for your cooked rice.

FACTORS AFFECTING SHELF LIFE

Several factors can impact how long cooked rice stays fresh in the fridge. Temperature is crucial, as bacteria multiply rapidly at temperatures between 40°F (4°C) and 140°F (60°C). In food safety, this temperature range is so-called the temperature danger zone (TDZ). The temperature danger zone refers to the range of temperatures in which bacteria multiply more rapidly. Within this range, bacteria can double in number every 20 minutes, potentially leading to foodborne illnesses if proper precautions are not taken.

At temperatures below 40°F (4°C), bacterial growth significantly slows down, and most bacteria become dormant. Cold storage, such as refrigeration, is an effective method to keep food out of the temperature danger zone. However, it is important to note that refrigeration only slows bacterial growth and does not kill bacteria. Therefore, even when stored in the refrigerator, cooked rice should still be consumed within its recommended shelf life (4 to 6 days) to minimize the risk of foodborne illnesses.

Furthermore, moisture is a contributing factor to rice spoilage as it provides an ideal environment for bacteria and mold to thrive. This can be prevented by thorough draining and storing in containers or bags with airtight seals. Also, always use clean utensils when handling cooked rice, and avoid leaving it at room temperature for extended periods, as this provides an opportunity for bacteria to multiply. Ideally, practice the “2-hour rule”, wherein perishable foods are not left at room temperature for more than 2 hours.

SIGNS OF SPOILAGE

To ensure food safety, it’s important to recognize the signs of spoiled cooked rice. If the rice has an off odor, strange texture, or appears moldy, it’s best to discard it immediately. Consuming spoiled rice can lead to food poisoning, which can cause symptoms like vomiting, nausea, and diarrhea.

Bacillus cereus is a common bacterium that can cause rice spoilage. Originating from soil, it can contaminate rice during cultivation or processing. Unlike visible signs of spoilage, B. cereus can multiply in cooked rice without altering its appearance, yet it can still pose a health risk if consumed. Remarkably, B. cereus can multiply by 1,000,000 in just 8.6 to 10.3 hours.

Another bacterium that can spoil rice is Clostridium perfringens. It is commonly found in the environment, including soil and dust. If cooked rice is not cooled and stored properly, this bacterium can multiply rapidly and produce heat-resistant spores. When the rice is later reheated inadequately, these spores can germinate and release toxins that cause food poisoning.

If rice contains additional ingredients, it may also harbor other pathogens. From May 1951 to January 1960, Japan experienced 166 recorded cases of izushi-related outbreaks, resulting in a mortality rate of 35% with 58 deaths. Izushi is a home-prepared food comprising raw fish, vegetables, cooked rice, malted rice (koji), salt, and vinegar. The bacterium responsible for these cases of food poisoning is Clostridium botulinum.

In addition to bacteria, mold can also spoil rice. Various types of molds, such as Aspergillus and Penicillium species, can contaminate rice. Mold growth on rice is visible as fuzzy patches or discoloration, and it can produce harmful toxins

PROPER STORING OF COOKED RICE IN THE FRIDGE

It is critical to quickly cool down cooked rice after cooking to ensure safe storage. Bacteria flourish in warm conditions, thus room temperature storage is ideal for them. Divide the cooked rice into smaller portions and store them in shallow containers to speed up the cooling process. Use an ice bath or a cooling rack to accelerate the procedure. Remember that damaged or ill-fitting containers can jeopardize the storage environment. Once the rice has cooled, immediately place it in the refrigerator, keeping the temperature below 40°F (4°C) to reduce the possibility of bacterial growth.

To maximize the shelf life of cooked rice in the fridge, store it in small portions that you plan to consume within the next few days. This reduces the need for reheating of rice multiple times, minimizing the risk of bacterial contamination.

References

J. Jay, M. Loessner, D. Golden (2005). Modern Food Microbiology (7th edition). Springer.

G. Cooper (2018). Food Microbiology. Library Press.

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Instant coffee is a popular beverage choice for those seeking convenience in their daily routines. Whether you’re traveling, camping, or simply need a caffeine boost at work, instant coffee offers a convenient solution. Instant coffee is a form of coffee that has been processed and prepared for quick and easy consumption. Unlike traditional brewing methods that involve grinding coffee beans, measuring water, and waiting for the brewing process to complete, instant coffee can be prepared almost instantly. Simply add hot water to a spoonful of instant coffee granules, stir, and it’s ready to drink. But amidst the hustle and bustle, one question lingers: Does instant coffee expire? Can that jar of powdered goodness still deliver a flavorful experience after months or even years on the shelf?

DOES INSTANT COFFEE EXPIRE?

Well, instant coffee does not have a strict expiration date. Instant coffee has a very low moisture content and water activity. According to the United States Department of Agriculture, instant coffee has a water activity of 0.2. Microorganisms have specific water activity requirements for growth. The water activity range in which most microorganisms can thrive is typically between 0.95 and 0.99. But since instant coffee has a very low water activity, microorganisms become dormant or unable to reproduce.

Various techniques are employed to control water activity in food products, including freezing, drying, salting, and the addition of preservatives. These methods reduce the amount of available water, making it unfavorable for microbial growth. For instance, freeze-drying or spray-drying coffee reduces the water activity. A low water activity is inhospitable for microbial growth and extends the shelf life of the product.

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Having said that, instant coffee is very shelf life stable as long as it is kept properly. According to a publication, a spray-dried instant coffee can last for several years provided that the product’s moisture content is less than 5% w/w. However, it is important to note that while the expiration date may not be a major concern for instant coffee, its quality can gradually deteriorate over time. This is caused largely by moisture absorption and flavor oxidation.

QUALITY DETERIORATION OF INSTANT COFFEE

We have often come across food packaging labels that advise us to store products in a cool, dry place, and there’s a valid reason behind it. Just like many processed food items, the quality of instant coffee deteriorates over time. However, using suitable packaging materials and proper storage techniques can slow down this process. It is advisable to keep the coffee away from direct sunlight and high temperatures, as heat and light can accelerate oxidation. Popular packaging options for instant coffee include cans, jars, and moisture-proof bags, which act as effective barriers against oxygen.

When instant coffee is exposed to oxygen, several chemical reactions occur, which can result in a deterioration of quality. The volatile flavor compounds in instant coffee readily react with oxygen, leading to their breakdown and a reduction in concentration. Consequently, the coffee may lose its distinct flavors and develop a stale or flat taste.

Oxidation becomes evident when instant coffee undergoes a browning effect, causing it to appear less vibrant and appealing. Many consumers may consider discarding a jar of instant coffee if the inside has clumped or hardened.

Despite its low moisture content, improper storage can still lead to moisture absorption in instant coffee due to its hygroscopic nature. This moisture comes from the surrounding air, and exposure to high humidity can compromise the quality and result in clumping or caking of the granules. When moist air enters the coffee container, the moisture condenses. If a jar of instant coffee is left open, the moisture can gradually penetrate the container, leading to the coffee clumping together. This caking effect starts when instant coffee reaches a moisture content of 7 to 8% w/w.

PROPER STORING IS KEY

The quality of instant coffee can deteriorate due to factors such as exposure to oxygen, moisture absorption, and flavor compound degradation, leading to a loss of freshness, flavor, and aroma. But there are several things that you can do to keep these things from happening.

Employing an airtight container is essential for proper instant coffee preservation. Place the coffee in a clean, dry container with a tight-fitting cover after removing it from its original package. This will create a barrier of defense against air, moisture, and odors, successfully maintaining the coffee’s flavor and freshness. Choosing non-reactive materials like glass or stainless steel, which are perfect for this use, can help you create the best storage conditions.

To prevent the entry of air and moisture, make sure to securely seal the container. Verify the lid or closure mechanism to guarantee a proper seal whenever you store the coffee. This practice will minimize oxygen exposure, decrease the likelihood of moisture absorption, and assist in preserving the coffee’s freshness. If you observe any issues with the container’s seal, such as improper sealing or damage, it is advisable to transfer the coffee to a new container or find an alternative airtight storage solution.

After transferring the instant coffee to a suitable container with a tight seal, ensure it is stored in a cool and dry location. As mentioned earlier, instant coffee is susceptible to heat, light, and humidity. Opt for a cool and dark spot, such as a pantry or cupboard, to shield it from direct sunlight. It’s important to avoid storing it near heat sources like stoves or ovens, as excessive heat and light can accelerate degradation, jeopardizing the coffee’s flavor and aroma. Additionally, steer clear of high humidity areas, such as near the sink or refrigerator, to prevent moisture absorption and clumping.

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Yogurt is a popular and extensively consumed dairy product recognized for its numerous health advantages, including probiotics that aid digestion. However, yogurt, like any perishable food item, can reach its expiration date, leaving consumers concerned about the risks of consuming old yogurt.

While we understand your concerns regarding expired food, it’s important to clarify that the “best by” date on yogurt packaging is intended to provide guidance on optimal freshness and quality. It does not necessarily mean that the yogurt becomes immediately toxic or unsafe to consume once the expiration date has passed. It’s worth noting that many food products in the market feature labels such as “Use-By,” “Best if Used By,” or “Sell-By,”. These are related to food quality rather than food safety. These dates indicate the recommended timeframe for consuming the product while it is at its peak quality. If you would like further information on this topic, I have previously addressed it in an earlier blog post, which you can read here.

HOW LONG BEFORE EATING EXPIRED YOGURT BEFORE YOU GET SICK?

Now back to the question. How long after eating expired yogurt before you get sick?

Well, according to FoodSafety.gov, yogurt should be consumed within 1 to 2 weeks from the date of purchase if refrigerated, and 1 to 2 months if frozen. Again the concern here is freshness and quality. When yogurt reaches its expiration date, the manufacturer no longer guarantees its freshness, quality, or taste. Consuming yogurt after its expiration date may provide various health hazards, albeit the severity of these risks varies. And there is no exact timeframe for how long it takes to get sick after eating expired yogurt, as it can vary depending on several factors. But in most cases, eating expired yogurt will cause no harm, provided that the dairy product has been properly stored (unopened and refrigerated or frozen).

As yogurt ages, the probiotics, which are beneficial bacteria, continue to ferment it. If the yogurt has passed its expiration date, you may notice a more pronounced sourness and acidity compared to its usual taste. This increased acidity is due to the production of additional lactic acid during the fermentation process. Although it might appear that the yogurt has gone bad, this is not the case. Expired yogurt, as long as it remains uncontaminated, will not cause any harm. This implies that only the live bacteria cultures intentionally added during the fermentation process are present.

The primary probiotic bacteria commonly found in yogurt cultures are Lactobacillus bulgaricus and Streptococcus thermophilus. These strains are responsible for the fermentation and transformation of milk into yogurt, contributing to its unique flavor and texture. While the taste and acidity of expired yogurt may differ, it can still be safely consumed as long as no external contaminants are present.

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But what if the yogurt has been contaminated with harmful bacteria?

Harmful bacteria called pathogens can contaminate yogurt and cause foodborne diseases in ingested. Symptoms of foodborne infections include minor stomach ache, vomiting, diarrhea, abdominal pain, and fever.

It’s important to note that consuming contaminated yogurt does not automatically guarantee that you will fall ill immediately. The onset and severity of symptoms can be affected by factors such as the level of spoiling and a person’s vulnerability to foodborne pathogens. Young children, persons with weakened immunity, and older people are more susceptible to food poisoning.

KEEPING YOGURT SAFE FOR CONSUMPTION

It’s essential to store yogurt correctly to reduce any possible risks. Make sure to put it in the fridge as soon as you as you purchase it. Yogurt should be appropriately stored at refrigerated temperatures to guarantee the viability of the bacterial cultures. Store yogurt in the refrigerator at or below 40°F (4°C). Keep it tightly sealed to prevent cross-contamination and maintain its freshness. Once opened, consume the yogurt within the recommended timeframe specified on the packaging. Yogurt’s live bacterial count can be reduced by heat, prolonged air exposure, and extended storage times. Hence, yogurt should be used before the expiration date.

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But if you did not consume the yogurt timely, you can observe signs of spoilage. It is best to discard yogurt if there is mold growth, unusual color, off-putting odor, or curdling. Visually inspect yogurt for any visible signs of spoilage even if the yogurt hasn’t reached its expiration date. When in doubt, throw it.

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Unlike walnuts and pecans, peanuts are grown beneath the soil. And for this reason, they are prone to infections, especially aflatoxins. Aflatoxins are produced by the soil-dwelling fungi (mold) Aspergillus flavus and A. parasiticus. In peanuts and other nuts and grains, it is the most important of the mycotoxins from a human health perspective.

Aflatoxins are quickly and widely absorbed from the gut and are metabolized to toxic epoxides in the liver. These epoxides bind to and harm vital cell components like DNA, RNA, and protein enzymes. The primary clinical outcome of aflatoxin consumption is liver damage in all animal species. According to epidemiological studies, aflatoxins and the hepatitis B virus are cocarcinogens, and the risk of liver cancer is higher in areas where both aflatoxins contamination and hepatitis B are prevalent.

Internationally, aflatoxins in peanuts are required to not exceed 15 μg/kg. This considerably very low MRL (maximum residue limit) ensures that peanuts with high concentrations of aflatoxins cannot be traded. In the United States, the Food and Drug Administration (FDA) has set the allowable limit of aflatoxin levels in peanut products at 20 ppb.

Fortunately, there are several ways to remove aflatoxins in peanuts.

In commercial operations, aflatoxins are regularly removed from food or food ingredients. Solvent extraction methods have been used in most cases. Some foods or food ingredients have been treated with appropriate chemicals to inactivate aflatoxins. Some chemicals, such as ammonia, hydrogen peroxide, and sodium hypochlorite, have been found to be effective at inactivating aflatoxins.

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Let’s discuss further.

WHAT IS AFLATOXIN?

Mycotoxins are toxic secondary metabolites produced by certain fungi. When consumed in large amount or regularly may cause certain cancer. Of all mycotoxins, aflatoxins have unquestionably been the most studies. Consumers have been aware of their existence since 1960, when over 100, 000 turkey poults in England perished after consuming imported peanut from Africa and South America.

Aflatoxin is classified into two types, B1 and G1. Each of them has several subtypes. Aflatoxin B1, produced by A. flavus and A. parasiticus, is thought to be the most potent. In fact, it has been classified as carcinogenic (Group 1) to humans by the International Agency for Research on Cancer (IARC). For more discussion on these types of aflatoxin, refer to this file.

Aflatoxin production has been shown to occur in many food products, which include nuts, dried fruits, and cereals. In general, toxin production is directly related to a mold strain’s growth rate. In microbiological media suitable for mold growth, Asp. flavus strains can produce optimum concentrations of aflatoxin at 91°F (33°C), pH 5.0, and Aw (water activity) of 0.99. Some toxin can be detected within 24 hours under optimal growth conditions.

In peanuts, aflatoxin formation occur primarily during the curing of peanuts after they have been removed from the soil. Hence, it is crucial to perform proper handling and storage to control the growth of aflatoxins. Moisture and temperature during storage should especially be given more attention. They are the two most important factors that affect aflatoxin formation. The presence of aflatoxins in peanuts is obvious if there is discoloration, visible mold growth, and the nuts are shriveled.

Aspergillus spp.-contaminated peanuts. Source

With that being said, here are 5 effective methods that you can do you remove aflatoxins from peanuts.

5 EFFECTIVE METHODS OF REMOVING AFLATOXINS IN PEANUTS

Aflatoxin contamination can occur in the field prior to harvest, during harvesting, or during storage and processing. While certain treatments have been found to reduce aflatoxin formation in peanuts, the most effective way is to avoid it in the first place. This is not always possible. But there are technologies and methods that can prevent contamination that would otherwise occur.

A variety of industrial food-processing methods can also be used to manage the aflatoxins in peanuts. Some of these can also be performed at home. As simple as sorting by color, screening, and lot separation (either with or without blanching) can reduce the toxin levels. In subsistence farming situations, the manual sorting of inferior nuts is also an option. Aflatoxins are thought to be heat stable, but roasting peanuts can reduce B1 aflatoxins by 50–80%.

Sorting and cleaning

Sorting and cleaning is the simple yet effective way for removing aflatoxins from peanuts. This entails removing any discolored, moldy, or damaged and shriveled peanuts from the batch because they are more likely to contain aflatoxin. To remove any dirt or debris, peanuts can be washed in clean water. Although this method is simple and easy to use at home, it may not remove all of the aflatoxin found in peanuts. Hence, this should be combined with another method.

In some practices, water is treated so that the process is more effective. For example, peanuts may be soaked in electrolyzed acidic water. Electrolyzed acidic water has a low pH of around 2.5, and is used as an effective disinfectant in food contact surfaces. One study has found that soaking grains in electrolyzed acidic water for 15 minutes can reduce 80% to 90% of B1 aflatoxin in peanuts.

Roasting

One of the most widely used techniques for removing aflatoxin from peanuts is roasting. High heat causes the aflatoxin molecules in peanuts to disintegrate, rendering them safe to consume. It’s crucial to remember that not all roasting techniques are equally efficient. As already mentioned, aflatoxins are heat stable. Studies say the optimum temperature for the production of aflatoxins is between 81°F (27°C) and 86°F (30°C). But they can withstand heat at normal cooking temperatures.

It has been demonstrated that dry roasting, which involves roasting peanuts without any additional oil, is more efficient at lowering aflatoxin levels than oil roasting. Additionally, to ensure that all aflatoxin molecules are destroyed, peanuts must be thoroughly and evenly roasted. Dry roasting is typically done on a very high heat.

To remove aflatoxins from peanuts properly, ensure to reach a temperature of 320°F (160°C) or higher. This study has shown that at a temperature of 320°F or higher, aflatoxins can be completely degraded. Another study showed that adding sodium chloride and citric acid can substantially improve the effectiveness of the process. If you wish to replicate the process, the authors recommend using up to 5% of citric acid. More than that may adversely affect the taste of peanuts.

Chemical treatment

Commercially, chemical treatment to remove aflatoxins in peanuts is widely practiced. What is involved in this method are common disinfectants or sanitizers in the food industry. One of them is hydrogen peroxide, a strong oxidizer. The peanuts are soaked in a hydrogen peroxide and water solution for a set amount of time before being thoroughly rinsed. One study said that treating peanuts with 0.075% of hydrogen peroxide for 1 minutes can reduce aflatoxin levels by up to 90%. Another good thing is that hydrogen peroxide residue can be removed by drying. Furthermore, it is environmentally friendly since it breakdowns into oxygen and water once exposed to light.

Although this method has been shown to significantly reduce aflatoxin levels in peanuts, it may also have a subtle effect on the taste and quality of the peanuts.

Other chemicals used to remove aflatoxins in peanuts include ammonia, sodium hypochlorite, and benzoyl peroxide.

Irradiation

Irradiation is one of the most effective methods in making foods shelf life stable, in general. But its high cost required makes it less utilized. Irradiation can remove aflatoxins by exposing the peanuts to ionizing radiation to break down the aflatoxin molecules. Most applications of irradiation require a maximum overall average dose of 10 kGy (kilogray).

For the purpose of microbial reduction, the doses range between 1 to 10 kGy. However, the outcome is positively correlated with an increase in the radiation dose. In one study, a 10 kGy dose reduced the toxin levels in peanuts to 58.6. Another study used lower doses of 4, 6, and 8 kGy, which reduced the aflatoxin levels to 7.6%, 17.3%, and 23.25% respectively. Nonetheless, irradiation is a viable option in reducing the aflatoxins in peanuts to below the maximum allowed levels.

While effective, the irradiation process may become less appealing to consumers who are reluctant to consume irradiated foods due to possible exposure radiation. It is crucial to remember that the radiation used to irradiate food is extremely low and has been approved as safe by regulatory bodies such as the Food and Drug Administration (FDA) and World Health Organization (WHO).

Furthermore, the taste, texture, or nutritional value of the peanuts are unaffected by irradiation. Peanuts are rich in proteins and fats. And these macronutrients are barely unaffected by radiation at usual doses.

Biological control

Biological control is a technique for removing aflatoxins from peanuts that involves using naturally occurring predators or competitors of the fungus that causes the toxin. Many factors influence a fungus’s ability to compete for a host. These include the soil type, pH level, water content, mineral available, nitrogen and carbon availability. The soil microbiome, primarily fungi and bacteria, influences fungi’s ability to produce secondary metabolites.

Using a strain of the A. flavus that does not produce aflatoxins is one example of bio-control. Aflatoxin levels in peanuts are decreased when this strain is introduced to the soil where peanuts are grown because it outcompetes the strain that produces the toxin. This 2020 study evaluated 18 non-aflatoxigenic strains of A. flavus. 6 of them reduced the aflatoxin levels produced by the native aflatoxigenic strains by 50%. Although promising, this strategy faces challenges that prevent it from being a clear solution to reducing aflatoxins in peanuts. For example, its biology is not well understood due to the diversity of A. flavus.

An alternative to this is using other species that can effectively affect the fungi from producing aflatoxins.

In this 2018 Korean study, the authors used Aspergillus oryzae M2040, a strain isolated from fermented soybean. 1% inoculation level of the A. Oryzae strain showed that it can effectively displace A. flavus and inhibit aflatoxin production.

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Another example is the bacterium Bacillus subtilis, whose many strains are safe for human consumption. It also produces enzymes that break down aflatoxins. This Japanese study used strains of B. subtilis that proved to be inhibitory on the growth of both A. flavus and A. parasiticus.

References:

Y. Motarjemi, G. Moy, E. Todd (2014). Encyclopedia of Food Safety. Academic Press.

Y. Motarjemi, H. Lelieveld (2014). Food Safety Management: A Practical Guide for the Food Industry. Academic Press

G. Cooper (2018). Food Microbiology. Library Press.

J. Jay, M. Loessner, D. Golden. (2005). Modern Food Microbiology (7th edition). Springer.

B. Ray (2005). Fundamental Food Microbiology (3rd edition). CRC Press.

I. Shaw (2013). Food Safety: The Science of Keeping Food Safe. John Wiley & Sons, Ltd.

The post How To Remove Aflatoxins From Peanuts? appeared first on The Food Untold.

Orange juice is one of the most popular beverages around the world. This beverage can be a refreshing start to the day or a tasty addition to your meals. It can also be a part of a healthy diet. An eight once serving of orange juice gives one day’s worth of vitamin C. However, if you are unsure about its shelf life, it is critical to understand how long orange juice lasts before spoiling or losing its taste and nutritional value.

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How long does orange juice last? Does an unopened juice in paper carton (tetra) last longer in the refrigerator? How about that made from freshly squeezed orange? This guide explains how long you can keep orange juice before it goes bad, whether it’s fresh-squeezed, from a carton, or opened but unfinished.

FRESH-SQUEEZED JUICE LASTS 2 TO 3 DAYS IF REFRIGERATED

In terms of quality and nutrition, fresh-squeezed is the best. But it is the least shelf-life stable of all forms of orange juice. It does not contain preservatives or additives and not thermally processed. For this reason, it typically only lasts about 2 to 3 days when refrigerated, and only 2 hours at room temperature. If the juice contains the pulp, it goes bad much quicker. For safety reasons, it is better to consume freshly squeezed orange juice within this timeframe. Ideally, consume orange juice the same day the oranges were squeezed.

If you won’t be able to consume extra fresh-squeezed orange juice, put it in an airtight container and place it in the freezer. Frozen orange juice is safe indefinitely. But it is recommended to consume it within 6 months as its quality deteriorates over time.

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ORANGE JUICE IN CARTON IS PASTEURIZED AND SHELF-LIFE STABLE

Orange juice in paper carton is more shelf-life stable than freshly-squeezed. It has undergone pasteurization, a type of food preservation method. This mild heat treatment is used generally to destroy pathogens (disease-causing bacteria), inactivate enzymes, and extend shelf life. This is the same method used for liquid egg, milk, and beer. But in the case of fruit juices, the main goals are to lower the bacterial count and inactivate enzymes since fruit juices typically do not contain pathogenic microorganisms.

Another reason for its stability is the preservatives it contains. Common preservatives used for orange juice include citric acid, sodium benzoate, and sorbic acid.

If you bought orange juice in carton displayed on a shelf, you can safely store it in the pantry or in a cool, dark place. This type of product is pasteurized and contains preservatives so it is safe unrefrigerated. Unopened, it can last for up to 1 to 1 1/2 years. After being opened, carton orange juice has a shelf life of 7-10 days on average. This can, however, vary depending on the brand and storage conditions. Before consuming any juice, always check the expiration date on the carton and discard any juice that appears spoiled or smells sour.

Another type of orange juice is that found in the refrigerated section of supermarkets. Supermarkets store this type to keep it fresh and prevent it from spoiling. If you purchased orange juice from the chilled section, do the same thing when you get home—store it in the refrigerator if you do not intent to consume it immediately. It will spoil in 2 hours If left unrefrigerated. Unopened, refrigerated store-bought orange juice should be safe to consume 2 weeks past its printed best-by date. If opened, consume it within 7 to 10 days.

WHY ORANGE JUICE GOES BAD

Orange juice spoils due to oxidation, which results in a sour taste and a change in color. When you open a container of orange juice, it begins to oxidize, allowing microorganisms to enter. Furthermore, if the juice contains pulp, the pulp will become bitter. Pulpy juice is especially susceptible to bacterial growth and fermentation, a process where the sugars are converted to alcohol. Even if the orange is not opened, the natural sugars in it will begin to convert into alcohol and carbon dioxide. Because of the fermentation process, the juice tastes like wine or beer. Fermentation in the juice has started if it has become fizzy.

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If an orange juice is already spoiled, there are several signs that will confirm it.

Fresh orange juice is sweet and fruity. But a spoiled one is sour or acidic. The odor resembles vinegar or alcohol. And when you taste it, it is either bitter or fermented (like wine). It’s important to remember that juice can still contain harmful bacteria even if there are no obvious signs of spoilage.

In packaged orange juice, one good indication is the bulging of the container. Gas has already been produced inside as a result of fermentation so discard it.

The post How Long Does Orange Juice Last? appeared first on The Food Untold.