There are six factors that affect bacterial growth, which can be referred to by the mnemonic FATTOM :. Foods that have the FATTOM conditions are considered potentially hazardous foods PHFs. PHFs are those foods that are considered perishable. PHFs are foods that support the growth or survival of disease-causing bacteria pathogens or foods that may be contaminated by pathogens.

One of the most important factors to consider when handling food properly is temperature. Table 3 lists the most temperatures to be aware of when handling food.

The range of temperature from 4°C and 60°C 40°F and °F is known as the danger zone , or the range at which most pathogenic bacteria will grow and multiply.

Pathogen growth is controlled by a time-temperature relationship. To kill micro-organisms, food must be held at a sufficient temperature for a sufficient time.

Cooking is a scheduled process in which each of a series of continuous temperature combinations can be equally effective. For example, when cooking a beef roast, the microbial lethality achieved at minutes after it has reached an internal temperature of 54°C °F is the same as if it were cooked for 3 minutes after it had reached 63°C °F.

Table 4 show the minimum time-temperature requirements to keep food safe. Other time-temperature regimens might be suitable if it can be demonstrated, with scientific data, that the regimen results in a safe food.

Figure 1 illustrates the top 10 improper food-handling methods and the percentage of foodborne illnesses they cause. This section describes each food-handling practice outlined in the top 10 list and the ways to prevent each problem. Many people think that once a food has been properly cooked, all disease-causing organisms pathogens have been killed.

This is not true. Some pathogens can form heat-resistant spores, which can survive cooking temperatures. When the food begins cooling down and enters the danger zone, these spores begin to grow and multiply. If the food spends too much time in the danger zone, the pathogens will increase in number to a point where the food will make people sick.

That is why the cooling process is crucial. Cooked food must be cooled from 60°C to 20°C °F to 70°F in two hours or less, AND then from 20°C to 4°C 70°F to 40°F in four hours or less. Even in modern walk-in coolers, large cuts of meat will not cool down properly.

Neither will whole poultry. or more of soup, stews, gravy, etc. However, you can cool these foods down quickly by using one or more of the following methods depending on the type of food being cooled:. Advance preparation is the cause of many food-poisoning outbreaks, usually because food has been improperly cooled.

Often, foods that are prepared well before serving spend too much time in the danger zone. This may happen for one or more of the following reasons:. Many people carry pathogens somewhere on or in their bodies without knowing it—in their gut, in their nose, on their hands, in their mouth, and in other warm, moist places.

People who are carrying pathogens often have no outward signs of illness. However, people with symptoms of illness diarrhea, fever, vomiting, jaundice, sore throat with a fever, hand infections, etc. are much more likely to spread pathogens to food. Another problem is that pathogens can be present in the cooked and cooled food that, if given enough time, can still grow.

These pathogens multiply slowly but they can eventually reach numbers where they can make people sick. This means that foods that are prepared improperly, many days before serving, yet stored properly the entire time can make people sick.

Some pathogens are more dangerous than others e. coli, campylobacter. Even if they are only present in low numbers, they can make people very sick. A food handler who is carrying these kinds of pathogens can easily spread them to foods — usually from their hands. Ready-to-eat food is extra dangerous.

Ready-to-eat food gets no further cooking after being prepared, so any pathogens will not be killed or controlled by cooking. Many restaurants prepare some of menu items in advance or use leftovers in their hot hold units the next day. In both cases, the foods travel through the danger zone when they are cooled for storage and again when they are reheated.

Foods that are hot held before serving are particularly vulnerable to pathogens. In addition to travelling through the danger zone twice, even in properly operating hot hold units, the food is close to the temperature that will allow pathogens to grow.

Hot hold units are meant to keep hot foods at 60°C °F or hotter. At or above this temperature, pathogens will not grow. However, a mistake in using the hot hold unit can result in foods being held in the super danger zone — between 20°C and 49°C 70°F and °F , temperatures at which pathogens grow very quickly.

We know that many raw foods often contain pathogens, yet certain foods are often served raw. Some examples include:. These foods have caused many food-poisoning outbreaks. Always remember: you cannot tell if a food contains pathogens just by look, taste, or smell.

Foods from approved sources are less likely to contain high levels of pathogens or other forms of contamination. Approved sources are those suppliers that are inspected for cleanliness and safety by a government food inspector. Foods supplied from unreliable or disreputable sources, while being cheaper, may contain high levels of pathogens that can cause many food-poisoning outbreaks.

Fly-by-night suppliers trunk sales often do not care if the product is safe to sell to you, but approved suppliers do! Because of this invention, we started to understand the nature of microorganisms.

Development of new and better microscopes together with better analytical techniques led to increased knowledge of bacteria, moulds and fungi.

To fight these pathogens, an emerging industry of synthetic antibiotics started to grow. Over the years, millions of synthetic products and microorganisms have been screened and characterised.

Penicillin is perhaps one of the most famous antibiotics known to fight bacterial infections. Before the discovery of this antibiotic, diseases like tuberculosis, pneumonia and gonorrhoea, could not be treated.

However, after some decades, resistance to antibiotics became evident. This led to an EU ban of antibiotics used in livestock animals in The industry had to look for alternative antimicrobial agents. First, we will look at what makes bacteria, moulds and yeast grow. Other microorganisms like parasites, protozoa and viruses are also present in the food and feed industry but will often have more complex mechanisms and are not covered here.

Microbial growth can be controlled either by prevention or inhibition — using an antimicrobial agent. Although microorganisms are very small in size, too small to be seen by the eye, they cause substantial economic losses each year for both the food and feed industry.

Bacterial infections caused by Salmonella , Campylobacter and Escherichia Coli are perhaps the most common infections causing billion-dollar losses. Reports estimate that Salmonella and Campylobacter infections in the poultry industry are responsible for 9 out of 10 reported food-borne diseases globally.

Coliform infections E. coli also cause major concerns related to mortality in chickens. Aquafeed is a growing business globally. However, the industry faces big challenges due to microbial diseases contributing to losses in the sector. An estimate published in Business World magazine Feb.

As mentioned earlier, antibiotics have been used for decades to fight bacterial diseases. Emerging resistance and the ban of antibiotics in the European Union from have affected this multi-billion dollar industry enormously.

Alternatives have been tested with varying results. Several technologies have been developed to control unwanted microorganisms in food and feed.

Both physical and chemical sterilisation methods can be applied. This heat treatment will prevent growth of microorganisms like Salmonella and E. Two physical methods commonly used in the dairy industry are pasteurisation and sterilisation.

When milk is pasteurised , it is heated to a temperature that will kill microorganisms without having a detrimental effect on the taste of the milk. The heat treatment is usually followed by a quick cool-down. Sterilisation occurs when a higher temperature is reached. This method not only kills the microorganisms bacteria, fungi, viruses, etc.

It is possible to use sterilisation in combination with, for instance, ultraviolet radiation. Sterilisation with chemical agents, alone or in combination with heat, is another method.

Chemical agents include: chlorine dioxide gas, phenol derivatives, guanidine compounds and hydrogen peroxide gas. Organic acids are widely used in animal feed. They have an excellent antibacterial effect on bacteria, mould and pathogenic yeasts. Organic acids include formic, fumaric, lactic, benzoic, propionic, and citric acids.

Inorganic acids include hydrochloric, sulfuric, and phosphoric acids. Salts of acids also have been used as acidifiers, including calcium-formate, potassium-diformate, sodium-diformate, and sodium-fumarate.

Blends of acidifiers are often commercially available because organic and inorganic acids may have a synergistic effect. In addition, some commercial acidifiers contain protected acids that are coated with fatty acids or other molecules, mainly to allow the release of the acid in a targeted location in the gut with the goal to improve effectiveness Kansas State University, Upadhaya et al.

The animal feed industry uses acidifiers in a number of different applications. Here are some examples of applications where Borregaard's unique SoftAcid products perform very well:. The EU Register of Feed Additives provides an overview of a limited number of authorized feed additives.

Some of the products are currently under re-evaluation, implying that changes might occur in the near future. Organic acids and their salts are listed as technological feed additives. In addition, there are compounds divided into sub-groups according to their functionality: acid regulators, zootechnical additives, preservatives and silage additives.

Pure organic acids often used in the feed industry today are formic, fumaric, lactic, benzoic, propionic, and citric acid. Salts of organic acids buffered acids have also been used as acidifiers, along with blends.

Borregaard's unique SoftAcid® technology consists of organic acids and modified lignosulfonic acid. Organic acids have two functions as antimicrobial agents. Their primary antimicrobial action is through pH depression. In addition, the ability of the organic acids to change from undissociated to dissociated form, depending on the environmental pH, makes them effective antimicrobial agents.

An acid in the undissociated form can freely diffuse through the semipermeable cell wall of the microorganism into their cell cytoplasm Figure 2.

A change in pH will suppress cell enzymes and nutrient transport systems Lueck, Figure Undissociated acid diffuses through the semi-permeable cell wall of the microorganism. Organic acids with higher pKa values are more effective preservatives over a wider pH range because of more acid in its undissociated form in the relevant pH range.

Their antimicrobial efficacy generally improves with increasing chain length Foegeding and Busta, Different types of acidifiers exist, but we recognise some common features regarding how they work:. Therefore, it makes sense to improve the efficiency of turning feed into animal growth.

In Germany, the largest economy in the EU, more than 70 kg of pork and poultry are consumed per capita per year, showing the scale of the need to improve feed efficiency, cost of production and environmental impact. Controlling the balance of the intestinal microbiota is the foundation of a profitable modern livestock operation.