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Hey everyone,just had some pasta for dinner that had ricotta cheese in it.Was worried when I was eating it that it was in the bad food/listeria category but still ate it! Just had a quick look on the net and some say to avoid it others say its fine.Does anyone know am just abit worried:(
The Australian food standards site says that ricotta is best avoided.
Was it heated with the pasta at all? Because its heated to over 60 degrees (I think) that will kill the listeria.
Try not to stress though, the risk of listeria is still very very small.
Thanks Ambah,it was a stir thru (Leggos) so the pasta was hot but not the sauce :( Guess I'll just have to hope for the best and not eat it again!
ness27 ricotta is ok to eat if cooked!!!!
so is brie, camabert and feta also when cooked!!!!!!
so relax and enjoy
So was the ricotta within the Leggo's sauce from a jar? If so, I would more than likely think it would be fine...
Yeah thats right in was a spinach and ricotta sauce in a jar.
Thanks feeb,as you can proberly guess I'm abit of a stress head!
I think its the cold/fresh stuff that you have to worry about? I think from a jar should be fine!
You will be fine!!!! that stuff wouldbe so processed that there would not be listeria in it!
I asked my OB specifically about ricotta as I make apasta with it and I LOVE it and had been missing it SO much. She told me to go for it (she is quite relaxed) as long as the ricotta is from a reputable shop/supermarket etc and not home made on a farm or something.. she said as long as it is pasteurised etc as all Aus cheese would be I shouldnt stress too much as the chances are so so so low...
I read somewhere that packaged food, such as tinned and canned, has a very low risk, as it would have required contamination before being packaged, which is a small possibility. I have eaten things out of jars (parmesan stuffed olives) with this in mind, so I am sure you will be fine. If you are worried, just avoid it, or heat it up in Microwave, but no point stressing now that you have eaten it (I know that is hard tho :))
Thanx guys :) You've really helped me feel better,will just try and avoid this sort of stuff from now on.
p.s. it was so delicious though! Haha!
I think it would be fine but probably would steer clear in the future - more so for stress levels! The risk would be extremely minimal I believe.
Just for a bit more info:
Ricotta and feta are both not okay to eat in pregnancy due to Listeria. It is irrelevant if they are pasturised. It is the ph content of the cheeses which encourage the listeria bacteria. Pasturised cheese does still contain listeria if the ph content is correct. I personally have seen a case of listeria contracted (suspectedly) from ricotta cheese.
Cooking at a sustained temperature will kill the listeria bacteria. So eating these cheeses cooked is fine.
Deb would the risk be the same then from ricotta which is mixed in with a sauce - like the processed leggo's sauces etc in sealed jars etc? I would have thought processed jar food wouldn't have any listeria risk??
I wouldn't think so Ambah but I wouldn't be sure either way.
The risk of listeria is low even in high risk foods. But it is still a risk and I believe (but I am a cautious health professional!) it's a risk that you can easily avoid for a few months of life!
I would think that the risk in a jar of pasta sauce would be teeny if at all. But again, that's not something I know it's something that I think... I sound very evasive don't I?
No, you don't sound evasive! It would be a hard thing to know for sure.... Thanks Deb :)
This was taken from the Aust/NZ food standards website:
INFORMATION ABOUT LISTERIA AND LISTERIOSIS
What is Listeria?
Listeria is a group of bacteria found widely in nature e.g. in soil, water and the intestines of many domestic and wild animals, fish and birds. Listeria can survive for long periods of time in soil, leaf litter, sewage, silage, vegetation and water. Listeria is frequently found in food processing environments and has the ability to form biofilms and survive on apparently smooth surfaces.
There are six species of Listeria; however, Listeria monocytogenes or L. monocytogenes is the most common species that can cause illness in humans and animals. In humans, L. monocytogenes is the causative agent of listeriosis, a potentially fatal illness in at risk people. While the incidence of listeriosis is relatively low, it is important to public health authorities because of the high case-fatality rate of this infection. Eating contaminated foods is the most common means of contacting this illness.
What are the symptoms?
The majority of cases of listeriosis are so mild that they are thought to be just a mild viral infection or flu. Less common symptoms are diarrhoea, nausea and abdominal cramps.
The illness may progress to more serious forms, such as septicaemia, meningitis (or meningoencephalitis) and encephalitis. In pregnant women, listeriosis can lead to intrauterine or cervical infections, which may result in spontaneous abortion or stillbirth. Women who become ill during pregnancy should consult their doctor immediately.
As symptoms are often initially mild and may not present until some days to weeks after the infection occurred, sufferers may not be aware they have been infected and may not seek medical advice. Treatment is not always successful once a person has the disease.
INFORMATION ABOUT ‘AT RISK‘ PEOPLE
Who is at risk?
Listeria infection does not normally affect healthy adults and children. However, it can be very serious for pregnant women and their unborn children, new born babies, the elderly and persons whose immune systems have been weakened by disease or illness, such as those suffering cancer, leukaemia, AIDS, diabetes, liver or kidney disease and anyone on medication that can suppress the immune system (for example, corticosteroids such as prednisone or cortisone – but not topical creams and ointments), including organ transplant patients.
Differences in susceptibility exist among various subpopulations e.g. organ transplant patients are considered to be more susceptible to listeriosis than other at risk subpopulations (see Figure 1).
Figure 1: Relative susceptibilities for immunocompromised and non-immunocompromised
The risk of listeriosis increases with age even in the absence of an underlying disease. In Australia, the median age of non-pregnancy related infections is 68 years. Hence people older than 65-70 years need to consider taking precautions against contracting listeriosis.
How common is listeriosis?
Listeriosis is a rare disease. The reported incidence of the disease is much lower than for many other foodborne diseases, but the consequences of infection are severe. In Australia there are approximately 60 cases of listeriosis notified to health authorities each year. The majority of these are in elderly patients or people who have suppressed immune systems.
Most cases of human listeriosis are sporadic and the sources and route of infection are usually unknown, however, contaminated food is considered to be the major route of transmission. Incubation periods range from a few days up to three months.
A small number of infections (less than 10 per year) occur in pregnant women and their unborn child. However, the true incidence is unknown as such infections are often not investigated or diagnosed. Testing is not routinely conducted on miscarried foetuses.
How dangerous is listeriosis?
There is evidence to suggest that Listeria is a transitory resident of the intestinal tract in humans, with 2-10% of the general population being carriers of the organism without any apparent adverse health consequences. In susceptible populations the bacteria most often affects the bloodstream, the central nervous system or the pregnant uterus.
Manifestations of listeriosis include bacteraemia/septicaemia, meningitis, meningoencephalitis, encephalitis, miscarriage, stillbirth, premature birth, neonatal disease and prodromal illness in pregnant women. Listeriosis has a high mortality rate of up to 50% for maternal-foetal infections and around 20% for non-pregnancy related infections.
INFORMATION ABOUT LISTERIA AND FOOD
How does Listeria get into foods?
Australia has a well-deserved reputation for a safe food supply and food manufacturers and processors have implemented systems designed to prevent Listeria contamination. However, Listeria is widespread in the environment and ready-to-eat foods might become contaminated after processing or at some later stage between the processing plant and the consumer’s plate. Contamination might also occur through improper hygiene of food handlers, or by cross-contamination after contact with raw foods or contaminated surfaces.
Unlike most food poisoning bacteria, Listeria continues to grow slowly even at refrigeration temperatures. It will grow more rapidly at higher temperatures, so foods that have been kept for a long time and/or that have not been kept cold may represent a higher risk to susceptible people.
Listeria bacteria may be present in certain types of foods such as pre-prepared uncooked foods or pre-cooked foods that have been kept for some time.
What precautions should I take if I am ‘at risk’?
The foods most often associated with listeriosis are ready-to-eat foods that support the growth of Listeria; have a long refrigerated shelf life; and are consumed without further listericidal treatments i.e. don’t receive any further processing/cooking such as reheating to 74°C for 2 minutes.
Foods that are packaged (i.e. food fully encased in a wrap or container by the manufacturer and not intended to be unwrapped except by the final consumer) do not usually present the same risk as unpackaged food or food on open display at a delicatessen counter, smorgasbord, sandwich bar or salad bar, etc. This is because unpackaged foods are more likely to become contaminated by Listeria from other foods also on display. Also, it is not always known how long unpackaged foods have been on display.
For people at risk of acquiring listeriosis, it is advisable to eat freshly cooked or freshly prepared foods. Freshly cooked foods are safe because cooking destroys Listeria bacteria. Also, the opportunities for contamination by Listeria is minimised as there is only a very short time before the meal is consumed. Foods should be cooked to a minimum internal temperature of 74°C to destroy the Listeria bacteria.
Prepare foods such as fruit salads, green salads and vegetable dishes shortly before eating. Eat well washed, freshly prepared fruit and vegetables in preference to fruit and vegetable dishes that have been prepared in advance and stored chilled for long periods. Storing food in chillers does not prevent growth because Listeria will grow at refrigeration temperatures. Try to avoid stored food, as it is impossible to know by appearance, smell or taste whether food is contaminated.
Where possible, only prepare sufficient food for the meal, and avoid the accumulation of leftovers. If there are leftovers, they should be refrigerated promptly. While Listeria can grow slowly at low temperatures (<5°C), eating leftovers within a day provides limited opportunity for Listeria to grow.
Do not eat food if there is any doubt about its hygienic preparation or storage. Refer to the good food hygiene guide in the Listeria and food – advice for people at risk pamphlet and the detailed notes later in this document.
MAKING SAFER FOOD CHOICES
Control of Listeria in a food business is largely managed by hygienic processing, preparation, storage and handling of food. Nevertheless there are selected higher risk foods, and at risk consumers should avoid these foods, especially if there is uncertainty that hygienic practices have been followed. The following tables list examples of higher risk foods and safer alternatives. Even higher risk foods are safe if they are cooked or reheated to steaming hot throughout, and served hot.
Additional advice on selected foods
Cheese
Some cheeses have been associated with outbreaks of listeriosis overseas. While soft and very soft cheeses made from raw milk have been often implicated, these outbreaks have also included cheese made from heat-treated milk. All cheeses may be subject to post-process contamination, however the adoption of good manufacturing practices by the dairy industry minimizes the risk of contamination.
The fate of L. monocytogenes during cheese ripening is determined by the microbiological, biochemical and physical properties of the particular cheese and its ripening environment. For this reason, at risk consumers should exercise caution with certain types of cheeses. Cheeses that have undergone a heat treatment are safe to consume if packaged, stored and handled correctly. While cheeses sold unpackaged have a greater risk of becoming contaminated from other foods on display.
Mould ripened cheeses
Brie, Camembert, Blue, Gorgonzola, Stilton These cheeses are divided into two categories: white mould cheeses, which are surface ripened (i.e. Brie and Camembert) and blue mould or blue veined cheeses, with mould throughout the cheese (i.e. blue, Gorgonzola, Stilton).
The relatively high moisture content of the surface ripened cheeses, along with a nearly neutral pH in fully ripened cheese, allows rapid growth of Listeria bacteria. Mould ripened cheeses are also highly susceptible to surface contamination during ripening. These types of cheese should be avoided by at risk groups
Soft Italian style cheeses
Mozzarella, Provolone, Cacioccvallo, Bocconcini, Scamorze The heat treatment (typically 71-88°C) given to these cheeses is sufficient to inactivate any Listeria present, however opportunities exist for post processing contamination.
In general these cheeses are safe to consume by at risk groups if purchased pre packaged. Avoid these cheeses if purchased at a delicatessen counter.
Semi soft and hard cheeses
Edam, Gouda, Colby, Cheddar, Swiss, Emmentaler, Gruyere, Romano, Parmesan By definition these cheeses contain ≤40% moisture. Cheeses in this category include such varieties as Edam and Gouda (which can also be classified as semi soft) as well as Colby, Cheddar, Swiss, Emmentaler, Gruyere, Romano, and Parmesan, the last two of which are very hard grating cheeses.
Hard cheeses have longer ripening periods, reduced moisture content and lower pH and are unlikely to support the survival and proliferation of Listeria and are therefore generally safe to consume by at risk groups
Soft unripened cheeses
Cottage, cream, Neufchatel Includes white curd cheeses with high moisture content (sometimes referred to as acid curd cheese). Most of these cheeses receive a heat treatment, sufficient to destroy any Listeria present. In addition, the cheese pH ranges from 4.6–5.0, which is unfavourable for Listeria.
Cottage and cream cheeses are generally considered safe for at risk groups, however purchase only pre-packaged product and consume well within ’use-by dates’. Avoid purchasing from delicatessen counters.
Whey cheeses
Ricotta, Broccio, Ricotone Whey cheeses are cooked at 82-88°C, therefore Listeria will be completely inactivated during manufacture. However, the potential still exists for contamination during packaging. These cheeses have a high moisture content and growth of Listeria may occur if there is post-processing contamination.
At risk groups should avoid consuming ricotta cheese, especially from delicatessen counters.
High salt varieties
Feta Feta can support the growth of Listeria during the initial stage of ripening, and brine solutions in which the cheese is salted and/or ripened can serve as a potential source for these bacteria. Growth of Listeria will stop when the pH falls to 4.6 during ripening, however, the bacteria can survive for more than 90 days in feta although numbers will gradually decline during this period.
Feta cheese bought unpackaged from a delicatessen counter should be avoided. Feta cheese bought packaged, presents a lower risk than the mould ripened cheese, but is a higher risk than hard cheeses.
Processed cheese Processed cheese is prepared by grinding and blending one or more natural cheeses into a plastic mass. The ingredients are melted and the mass submitted to heat treatments ranging between 85-95°C or under pressure to 110°C or more for several minutes.
In general, pre packaged processed cheeses that have received a heat treatment are safe.
Unpasteurised milk
Unpasteurised (raw) milk represents a significant hazard and should be avoided. In Australia, unpasteurised cow’s milk is not commercially available. However it should be avoided if available from a farm. Similarly, unpasteurized goat, sheep or buffalo milk should be avoided.
There are food safety requirements and hygienic practices that must be applied throughout the whole Australian milk production and supply chain, including on-farm food safety programs and the mandatory application of pasteurisation to cow’s milk.
Dips
There is a large selection of dips available and the growth of Listeria in these products is dependent on the dip’s composition. Dips can generally be classified as dairy or non-dairy based. Dairy based dips are largely composed of cream cheeses, sour cream or yoghurt.
Factors to consider when purchasing dips include whether it is cultured (i.e. sour cream or yoghurt based) as high levels of culture organisms are likely to deter the growth of Listeria; the pH of the dip (the more acidic the more unfavourable to the growth of Listeria), the addition of preservatives, and whether the dips have been subject to a heat processing step sufficient to destroy any Listeria present. A cream cheese type dip commonly includes a heating step in its production.
Dips that are not sold pre-packaged by the manufacturer (i.e. purchased from a deli counter) should be avoided because of the risk of cross-contamination. If you are unclear whether the dip has had a heat treatment process applied to it, you may wish to contact the manufacturer.
Condiments e.g. mayonnaise and pesto
These products are safe if purchased pre-packaged by the manufacturer and are chilled. They are also safe if cooked.
Cooked and ready-to-eat meat or poultry products
Listeria may be present on raw meat and poultry products. Standard cooking treatments used by Australian manufacturers of processed meat and poultry products are more than sufficient to ensure any Listeria are destroyed.
The issue of whether Listeria can grow on cooked meat or poultry products is complex as the organism is able to grow on some products more easily than others. Factors such as pH, water activity, presence of competitive microorganisms, sodium nitrite and sodium chloride, length and temperature of storage, strain type and history all play a role in determining the fate of a product contaminated with Listeria.
Salami Studies on the behaviour of Listeria in salami have shown that growth is unlikely after fermentation and drying, but the organism may survive. A combination of low pH and low moisture prevent Listeria growing in these types of products. The risk from these products is lower than other ready-to-eat meat and poultry products.
Paté Paté should be avoided by at risk groups as the high water activity and pH of typical patés provide an ideal growth environment for Listeria.
Processed meat Listeria can grow on a variety of processed meat products at refrigeration temperature. Scientific testing has proven that cooked roast beef supported far less growth of Listeria compared to ham. This is likely due to the relatively low initial pH (5.8) of roast beef and the continued decrease of pH during the storage of the product.
Jellied meats and corned/silverside meat products have been implicated in illness from Listeria and should be avoided by at risk populations
Listeria will grow well on sliced chicken, turkey and ham. As a rule of thumb, Listeria will grow well on meat and poultry products of pH 6 or greater, and poorly or not at all on products near or less than pH 5.
Pre-packaged sliced meat and poultry products generally have long shelf lives, so product that has been contaminated with Listeria can have large numbers present by the end of its shelf life. If purchasing ready-to-eat meat or poultry products that are pre-packaged by the manufacturer ensure the package is intact and there is sufficient shelf life left on the product. Once the packet is opened there are opportunities for the product to become contaminated with Listeria, and as Listeria will grow slowly at refrigeration temperatures, it is advisable not to store these products for a prolonged time.
Ready-to-eat sliced meats purchased sliced from a deli (or put in a sandwich at a sandwich shop) or product that has been cut into smaller portions and rewrapped, for example at a supermarket, butchers shop or deli counter, are more likely to be contaminated as they have been exposed to more handling and the food preparation environment. These products should be avoided.
Meat and poultry products that have been cooked in their casing and marketed in the original package will be safe to consume providing the packaging is intact.
Note that meat and poultry products that are cooked in other foods such as quiche, fried rice, pizzas etc are safe as Listeria is destroyed in the cooking process.
Tofu
Tofu is made from soybeans and Listeria is not usually found in soy products. Handle hygienically, keep it refrigerated and use with 24 hours of opening the container.
Seafood
Fish and seafood may be potential sources of Listeria, due to their harvest from natural environments where the bacteria can be found. However, it is more likely that Listeria may enter seafood products during and/or after processing through poor hygiene or manufacturing practices, or from subsequent handling of product. This is a special concern for those products that receive minimal or no heat treatment before consumption.
Smoked salmon and trout Smoked salmon and smoked trout have a pH in excess of 6.0 and are usually salted to achieve an aqueous salt content of 3.5%. If Listeria is present in these products it is capable of significant growth, as they have a long shelf life. These products should be avoided by at-risk groups.
Live oysters and mussels Listeria is rarely isolated from fresh live oysters and mussels, however contamination of mussels is mainly due to contaminated processing environments. Smoked mussels have been associated with cases of listeriosis in Australia and New Zealand and should be avoided by at-risk groups.
Peeled prawns (cooked) Peeled prawns (cooked) can be extensively handled both at retail and post-retail, thereby increasing the possibility of recontamination. In addition, poor temperature control of retail chilling cabinets may allow the growth of Listeria if present.
Cooked peeled prawns in prawn ****tails, as sandwich fillings, or in pre-made salad should be avoided, due to the extensive handling of these products and possible time/temperature abuse during storage.
Products of plant origin
Ready-to-eat, or minimally processed, raw vegetable preparations are those that have undergone minimal processing such as trimming, peeling, slicing, shredding, washing or a combination of these and are presented for sale to the consumer in a ready-to-eat form. Examples include lettuce, lettuce mixes, coleslaw mix, and vegetable florets and pieces.
Listeria can survive and/or grow on most raw salad vegetables. The widespread practice of packaging and/or storing fresh produce in a modified atmosphere has extended the shelf life of these products and provided additional time for Listeria to grow. Therefore pre-packaged salads etc. should be avoided if they are consumed without further cooking. Buy your fruit and vegetables whole, and cut them up yourself. Remember to wash the outside before you eat or cut up these products.
LISTERIA AND FOOD HYGIENE PRACTICES
The following notes outline some simple food hygiene practices that will help reduce the risk of Listeria infection as well as reduce the risk of other foodborne illnesses. Activities that need to be considered include purchasing food; preparing food in the home; and eating out. Proper food hygiene practices at these times will assist in: preventing contamination of food by pathogenic bacteria that cause foodborne illness (mainly pathogenic bacteria and viruses); destroying potentially dangerous microorganisms, and preventing the growth of bacteria that may survive cooking.
It is important to emphasise that Listeria may grow at temperatures of 5°C or below. Refrigeration of food will prevent the growth of other pathogens, but Listeria will continue to grow slowly under refrigeration. Generally it is much safer to store food in the refrigerator than at temperatures above 5°C, but ensure that ready-to-eat food is stored for only short periods of time.
Placing food in the refrigerator will not always protect the consumer from foodborne illness because if the food is already contaminated illness may still occur. Preventing growth of bacteria alone does not necessarily reduce the chance of food poisoning.
Purchasing food
Which foods are safer food choices?
Australian consumers are usually able to choose from a variety of high quality foods. When purchasing foods for home, purchase what are considered safer foods in preference to others. Information on food choices is discussed separately.
If you enjoy a food listed as being of higher risk, purchase it but only include it in a cooked dish e.g. use soft cheese in quiches, peeled cooked prawns in stir-fry dishes, etc.
Why should I avoid ready-to-eat food from salad bars, sandwich bars, smorgasbords and delicatessens?
Opportunities for cross-contamination between foods occur when there are many unpackaged, high risk foods displayed together; where staff handle these foods; and where utensils and other equipment for example tongs and weighing scales, are used for many different types of foods.
Salad bars in supermarkets, buffets and smorgasbords, sandwich bars and delicatessens are examples of food displays where a great variety of unpackaged foods may be handled and come in contact with each other. Avoid purchasing foods from these types of display.
Why is ready-to-eat hot food safer if purchased ‘steaming’ hot?
Foods that are purchased ready-to-eat and hot are usually cooked chickens and other foods from the hot food section of supermarkets and take-aways. These foods have been cooked and are maintained hot until sold. Any contaminating bacteria may grow during the holding period if the food is not held hot enough (60°C or above). If the food appears ‘steaming’ hot it is usually hot enough to prevent the growth of Listeria.
What is the difference between ‘use by’ and ‘best before’ dates and why avoid foods that are out of date?
Manufacturers’ place ‘best before’ dates on food to advise consumers how long the food will maintain its quality if it remains in the sealed package. Food may legally be sold after its ‘best before’ date has expired provided it is safe and not damaged, deteriorated or perished in any way but it may not have the quality attributes of a ‘fresher’ product.
There may be a small risk that contamination has occurred and Listeria bacteria has grown in perishable products that have dates close to their ‘best before dates or with an expired ‘best before’ date. Do not eat these foods. If the package has been opened after purchase then there is more chance that bacteria may have contaminated the food so do not eat the food.
Manufacturers’ are legally required to place ‘use by’ dates on foods that will be unsafe to eat after the expiry date. It is illegal for food businesses to sell foods after the expiry of its ‘use by’ date. Do not consume these foods. Preferably buy and consume foods well within their ‘use by’ dates.
Always check packaged foods before purchase and only buy undamaged, unopened packages.
Preparing food at home
How do I wash my hands correctly?
This may seem a silly question but surveys show that people often do not wash or dry their hands correctly.
Hands may transfer bacteria from one food to another and from surfaces to food. Washing hands with warm water and using bar soap or liquid cleanser, rinsing and drying thoroughly on a clean hand towel or disposable paper towel removes transient microorganisms. Antibacterial soap is not required as ordinary soap is effective. Wash your hands with soap for at least 20 seconds and dry your hands thoroughly before preparing food, particularly before preparing ready-to-eat food. Moisture from wet hands can transfer bacteria to foods and surfaces so always dry thoroughly.
Air-drying, as the sole means of drying hands is not recommended because of the time needed to remove moisture compared with towel drying.
Because ready-to-eat food is eaten without further measures to reduce or remove bacteria, preventing contamination from the hands is particularly important.
How do I keep kitchen equipment clean?
Wash knives, cutting boards and kitchen appliances and dry thoroughly after preparing raw food to prevent contamination of cooked and ready-to-eat foods.
Raw foods are more likely to contain Listeria, as they have not been processed to destroy the bacteria. All equipment in contact with raw food should be washed in warm water and detergent and rinsed in hot water (taking care not to scald). Dishwashers are an excellent way to ensure equipment is rinsed in hot water. Equipment should be dried with clean cloths or paper disposable towels. This will remove moisture, which bacteria need to survive.
It is advisable to prepare food on chopping boards or other surfaces that can be washed in the sink or dishwasher. Avoid preparing food directly on benches, as they are difficult to wash, rinse and dry.
What temperatures should I keep food at?
If you are holding food hot, keep it very hot (60°C or hotter). Listeria does not grow at temperatures above 60°C. If you are keeping food hot to serve it later, keep it very hot (steaming or simmering) to prevent Listeria from growing.
If food is to be kept cold, it should be refrigerated shortly after cooking or after returning from shopping. Keep cold food cold (5°C or colder).
What should I check in my fridge?
The refrigerator should be set to operate at 5°C or colder though obviously not too cold, as foods will freeze. This temperature minimises the growth of bacteria in the food. Invest in a fridge thermometer from your local kitchen shop to check if your fridge is at the right temperature particularly when the weather gets warmer.
Listeria bacteria may survive and grow slowly on films of dirt (spilt food, drips from food, condensate, etc) on the inside of the refrigerator. Hence refrigerators should be cleaned regularly with warm water and detergent and wiped dry and any visible signs of food and mould removed. The frequency of cleaning refrigerators depends on the use. It is best to clear up spills as soon as possible.
Covering foods with a clean covering for example, plastic film, or placing foods in clean, sealed containers helps prevent airborne contamination, contamination from drips from other foods and from condensate in the refrigerator.
Store raw meat, poultry and fish separately from cooked and ready-to-eat food in the refrigerator. Store raw foods below other foods so there is no chance it will drip onto other foods. Raw meat, poultry and fish are particularly likely to carry pathogenic bacteria. Meat on plastic wrapped trays is liable to leak so the trays should be placed on a tray or other container that will catch drips, or unwrapped and the meat placed in a sealed container. Meat wrapped in paper may also leak, so take the same precautions.
Does washing raw fruit and vegetables help reduce the risk?
Raw fruit and vegetables may carry Listeria bacteria so thoroughly wash and dry raw fruit and vegetables before eating or juicing. Make sure you wash and dry fruit or vegetables just before you eat them as this will remove some bacteria and reduce the likelihood of the food being contaminated.
How do I defrost food?
Thaw ready-to-eat frozen food in the refrigerator or microwave. Do not thaw at room temperature, as the surface of frozen foods that are being thawed may reach temperatures that allow pathogenic bacteria to grow. Thawing in the refrigerator ensures surfaces of food do not reach more than 5°C. Thawing in the microwave is rapid and there is not time for bacteria to grow. These thawing practices are particularly important for ready-to-eat food, as there are no further opportunities to reduce or destroy bacteria. It is less important for raw foods, but is good practice.
Frozen raw foods that are not cooked from frozen (as instructed by some manufacturers for some products) should be thawed completely before cooking to ensure all parts of the food reach temperatures high enough to destroy bacteria.
Why should I cook foods thoroughly?
Raw meat, poultry and fish may carry pathogenic bacteria and thorough cooking provides a means of destroying most of the significant pathogenic microorganisms, especially Listeria.
Thorough cooking is particularly important where bacteria may be in the centre of a food, such as foods made of minced meat; where the food is very thick such as a rolled roast; or where the shape of the food makes heat penetration difficult.
Which foods should be cooked thoroughly?
Bacteria may be distributed to the centre of minced meat products (sausages, rissoles, patties, meat loaf, etc) and rolled joints, so it is important that these products are cooked through to the centre. This will eliminate pockets of uncooked food, which could contain bacteria.
Likewise, foods with cavities (e.g. whole chickens and turkeys) should also be cooked through to the centre cavity to destroy bacteria. If the cavity contains seasoning (stuffing) this should be thoroughly cooked to destroy any contaminating bacteria. It is preferable to cook the stuffing in a separate dish.
How do I know if food is cooked thoroughly?
Generally food is adequately cooked if the juices from the centre are clear. It is advisable to use a cooking thermometer to accurately measure the centre temperature of foods and to ensure it reaches at least 74°C. Likewise, follow cooking instructions on labels of prepared foods such as frozen chicken nuggets and frozen prepared meals. Note that some types of prepared foods are precooked and only need to be reheated while others require thorough cooking.
Soups, stews and similar wet dishes are above 74°C if the food is boiling or at simmering point. Stir these foods to ensure all parts of the food are hot.
How soon should I refrigerate leftovers?
Don’t leave foods to cool on the bench or stovetop for long periods of time. Once these foods stop steaming, put them in the refrigerator so they cool rapidly. Bacteria that have survived cooking may grow if food is left to cool for long periods of time at room temperature.
What is ‘reheating’ and why is it important to reheat foods to steaming hot?
The term ‘reheating’ refers to heating previously cooked food for example, leftover casserole, to a temperature and consistency that makes it appetising to eat. Some people prefer to reheat to just warm; other may like to reheat to very hot. If you are ‘at risk’ or are reheating food for an at-risk‘ person, ensure the food is reheated to very hot i.e. to at least 74°C. The aim is to destroy any Listeria that may have contaminated the food and grown while it was being stored.
Bring wet dishes to simmering point or a rolling boil. For solid dishes for example, lasagne heated in the oven, reheat rapidly and ensure that even the centre of the food is very hot. Ensure that all parts of food reheated in the microwave are very hot.
How do I reheat food safely?
It is good practice to reheat previously cooked food to at least 74°C (or steaming hot) for two minutes to destroy bacteria that may have contaminated the food since cooking. Although reheating cannot be relied upon to make food safe because reheating does not destroy toxins produced by bacteria such as Staphylococcus aureus, it will destroy Listeria.
Food that is ‘steaming hot’ means hot throughout the food and this visible indicator means it is hot enough to destroy bacteria.
Eating out
What should I eat if I am eating out?
Order menu items that are freshly cooked to order. This means that the food has not been held at ‘warm’ temperatures, which could allow growth of bacteria. If you cannot choose a freshly cooked hot menu item, then ensure that it is reheated to very hot and ask for further reheating if it is served warm.
Avoid pre-prepared salads and other pre-prepared chilled foods. For lunch, it may be best to bring something from home rather than buy something ready-to-eat from a sandwich bar but do keep the food refrigerated and make sure that your work fridge is operating at 5°C or less.
Flowerchild this is a great article..... I actually emailed all my friend on it.
I am glad it helped!
waaaaa it's all things I love doesn't that suck!? :lol: I've been avoiding seafood not so much because of the risk of Lysteria but more because it's too strong for my week stomach, the smell is just too much.