Raye Minor
05-06-2005, 06:34 AM
FOOD POISONING AND FOOD HYGIENE.
NB: this article is for personal interest and information only; it is not meant to be used for self diagnosis, treatment or commercial purposes.
Part 2: FOOD HYGIENE.
Introduction:
"It must be something I ate" is a common explanation given by people to explain a bout of acute diarrhoea or some other gastrointestinal upset. In many cases this will an accurate diagnosis".
In Part 1:
Food Poisoning, it was stated that there are an estimated 76 million cases of food poisoning in the United States every year and around 5 million in the United Kingdom.
The prime cause is bacterial but viral or parasitic infections are not uncommon. Bacteria highlighted included Salmonella, E.coli 0157:H7, Clostridium botulinum, Clostridium perfingens, Shigella and the most common; Campylobacter.
Viruses included hepatitisA and Norwalk like virus whilst parasites included Giardia lamblia and Crytoposporidium parvum.
The first section was primarily about the causes of Food Poisoning whilst here in Part 2 we look at ways of preventing Food Poisoning….. i.e. Food Hygiene.
The vast majority of food poisoning cases are minor but consider this:
Unlike Food Poisoning cases per se, most cases of Clostridium Botulinum poisoning occur in home-prepared food. Botulinum toxin is 15,000 more toxic than VX nerve gas! Botulinum toxin is 100,000 more toxic than sarin!
The threat of bacteria and their toxins as a tool for bio-terrorism is very real (e.g anthrax); it is unlikely they would cause significant mortality (death) but they could cause significant morbidity (disease) and have already caused widespread panic. This gives some idea of the potential potency of bacteria and their toxins.
Some additional Food Poisoning and Food Hygiene facts.
Pathogenic (harmful) bacteria grow best in the temperature range 59 - 113F (15 - 45C) except for Campylobacter which grows well up to 117F. (47C)
The optimum temperature for bacterial growth is 98.6F/37C which is human body temperature, apart from Campylobacter which has an optimum temperature of 107F/42C. This explains why Campylobacter is commonly associated with food poisoning from poultry; birds (avians) have a slightly higher ambient body temperature than humans at around 107F/42C.
This fact is utilized by Microbiology Laboratories; they isolate most bacteria at 98.6F/37C but isolate Campylobacter in incubators set at 107F/42F.
Bacteria divide every 15 - 30 minutes at optimum temp. (98.6F/37C)
Bacteria grow slowly at 113-122F (45-50C), but growth rate falls rapidly above 113F (45C)
Only a few bacteria can grow at more than 122F/50C.
However, the "danger zone"where harmful bacteria can multiply is almost always quoted as 40–140F. (5–60C) This is the temperature range to remember and food must not be allowed to linger in this zone.
Non sporing cells of food poisoning bacteria are killed at temperatures greater than 140F (60C) after exposure for 10 to 30 minutes or more, dependant on bacterial type.
The longer the exposure to high temperatures the higher the degree of bacterial destruction.
At lower temperatures bacteria growth is reduced.
At 45F (7C) bacteria virtually cease to multiply but do not die.
Extreme cold (freezing) does not kill the majority of bacteria.
Extreme cold (freezing) does not kill most viruses, but it does kill many parasites.
Food poisoning can occur when large numbers of bacteria (or spores), viruses or parasites survive, either directly (e.g. bacteria themselves) or indirectly (toxin production) and are ingested.
Bacteria that cause food poisoning will be invisible, the appearance, smell and taste of the food is generally unaltered.
Smoking will only preserve the outside of the meat, not the inside, from bacterial contamination.
Meats that are rolled (e.g brisket) carry additional risk and may be contaminated by handling then rolling the contamination to centre of the meat. Subsequent internal cooking temperature may then not meet that required to kill this bacterial contamination.
Ground meat carries a higher risk of Food Poisoning.
And remember; think of that single bacterium at time zero, under optimum conditions 7 hours later you will have 2,097,152 of the little blighters. But at two hours at optimum temperature that number is only 64.
So, what can be done to significantly reduce the risk of food poisoning.....?
Given that 97% of food poisoning cases are thought to be due to poor food hygiene the answer to this question is.....a lot!!
Food hygiene:
Curing and Smoking food. Foods have been preserved by smoke-curing for many hundreds of years, however it is important to make the distinction between smoking for preservation and smoking for texture and flavour.
Historically food was smoke-cured for preservation and the curing and smoking process were a lot more heavily applied than they are in the present day, when smoking is more concerned with texture and flavour.
Drying (curing) was of paramount importance because moisture is one of the prime prerequisites for bacterial growth. Salt accelerates the removal of water and hence retards bacterial growth.
Smoke (phenols etc) worked in tandem with drying by retarding the development of spoilage bacteria.
Because smoke-cured products nowadays tend to be a lot more mildly smoked and dried, in many instances these processes are not as effective as yesteryear with regards to prevention of spoilage by food poisoning agents. However, some protection will be imparted.
See appendix 2 for brine strength for use in the curing process.
Hot Smoking:
In essence the food is cooked and smoked at the same time with food typically being heated to an internal temperature of 145F (63C) or more, high enough to kill bacteria.
Hot smoking is a lot more tolerant of variations in temperature than cold smoking.
This is the predominant method of smoking in the United States.
Cold Smoking:
The food is smoked but NOT cooked, typically at temperatures of around 60F (15C) with a range of 50-85F (10–29C). However, some sources quote the ideal temperature as being 75-80F. (24-26C). True cold smoking temperature must not exceed 85F. (29C).
There is not really a lower cut off temperature for cold smoking and it is possible to cold smoke at significantly lower temperatures than the literature suggests. However, it does take longer to cold smoke satisfactorily at lower temperatures.
Cold smoking temperatures are not high enough to kill bacteria and correct food handling is essential if this method of smoking is utilized.
If a cooked product is required, food must be (separately) cooked adequately in addition to cold smoking. Cold smoking is more common in Europe.
Some cold smoked products are eaten raw (e.g Salmon) whilst others are cooked. (e.g. kippers – cold smoked herring)
In some parts of the world temperature and humidity may make cold smoking impossible.
The curing and smoking processes involved during cold smoking may inhibit bacterial growth.
Bradley Smoker as a Slow Cooker. The term "low and slow" is often used with regards to the Bradley Smoker; in effect the Bradley Smoker is a slow cooker.
The temperature typically associated with use of the Bradley Smoker is similar to that generally more universally accepted for slow cooking. (170F/70C to 280F/125C)
One major benefit is that less expensive cuts of meat can be used which still become tender and tasty as they slow cook.
It has been shown experimentally that slow cooking is a safe means of cooking with no more inherent risk than other means of cooking provided basic food hygiene standards are maintained.
The main potential problem specifically associated with "slow" cooking is: Power out: electrical or smoker failure:
Whilst food is cooking and once it’s done, food will stay safe as long as the cooker is operating at the correct temperature.
However, if no-one is at home during the entire "slow cooking" process and the power goes out for some reason and you are not sure exactly when, the food should be discarded even if it "looks" done.
If you are at home, finish cooking immediately by some other means. (eg gas grill, barbecue etc.)
Food should remain safe for up to two hours in the event of a power off/out incident.
There is not a specific risk associated with use of a Bradley Smoker in relation to Food Poisoning, what risk there is may be deemed universal risk. I.e. they are associated with all forms of food handling and cooking and not specifically a Bradley Smoker.
A couple of other points to ponder:
If modifying your Bradley Smoker to include, for example, a box and tumble dryer hose for use in the John Watkins/Grakka (see Bradley Smoker forum or Recipe Forum) cold smoking method be careful what the box is constructed from. Some materials (e.g. galvanised steel) must not be used and can lead to chemical residue contamination of food.
It is suggested that if you require specific advice in this area or other use of a Bradley Smoker then contact Bradley or post a question on the Bradley Smoker forum.
Read the instruction manual that comes with the Bradley Smoker.
Just as you would keep any other cooking utensil clean, ensure all parts of the Bradley smoker that come into contact with food are kept scrupulously clean. They are all dishwasher safe.
THE FOUR C’s OF FOOD HYGIENE.
First things first……. it is vitally important to buy or otherwise acquire good quality meat, poultry and fish from a reputable source.
Poor quality produce coming in to a particular food process will equate to poor quality produce out and may increase the risk of food poisoning.
No amount of smoking or curing can make a poor quality product into a good quality one!!
Ask yourself……… are you confident the food has been handled correctly before you acquired it!?
There are four simple headings to remember for good food hygiene, the best reference in my opinion refers to them as the 4C’s………
CLEANLINESS
COOKING
CHILLING
CROSS-CONTAMINATION.
This is sometimes referred to as Clean, Separate, Cook and Chill. (e.g. FightBAC! campaign) but in essence they are the same, 4C’s is easier to remember!!
Cleanliness:
http://www.susanminor.org/Rayeimages/food/shower.jpg
The spread of harmful bugs can be preventing by observing good personal hygiene and keeping work surfaces, utensils etc clean:
The recommended time to wash hands is at least 20 seconds in hot soapy water. Wash both before preparing food and at appropriate stages during the process.
Cover cuts and abrasions, if one becomes infected then stay out of any food preparation area.
Do not handle food if you are ill with a stomach problem, such as diarrhea and/or vomiting.
Keep dishcloths clean, wash regularly….. weekly is recommended.
Use smooth non porous cutting boards made of hard wood or plastic and discard if they become cracked. Wash thoroughly after use using a scrub brush and hot soapy water. (Remember, water must be hot enough to kill the bacteria, at least 140F/60C)
Always wash utensils thoroughly after use, do not mix those used for raw and cooked food.
Food processors or meat grinders must be taken apart and cleaned thoroughly after use, if items are not dishwasher safe then wash manually in hot water.
Use either a commercial kitchen cleaner or 1 teaspoon bleach to 1 quart of soapy water to disinfect work surfaces, sink drains etc.
Cooking:
http://www.susanminor.org/Rayeimages/food/cooking.jpg
Cook food to the proper internal temperature, this varies for different cuts and types of meat.
To ensure meat and poultry are smoked safely; two types of thermometer should be used. One is required to monitor air temperature in the smoker whilst the other is required to determine the internal temperature of the meat, fish or poultry. Some thermometers (e.g. Maverick ET-73) has 2 probes and performs this dual role.
Check the accuracy of thermometers. (See appendix 1)
Typical air temperature of the smoker will be 225F/100C or more when hot smoking.
Cooking times depend on several factors; examples include type of meat and size and baseline temperature of meat at start of cooking. It can take just a couple of hours to 14 hours or more to satisfactorily cook the contents of your smoker.
The recommended internal temperatures to slow cook various types of meat and fish are:
Poultry breast:............170F(77C)
Whole poultry and thighs:..180F (82C)
Ground chicken:............165F (71C)
Beef, veal and lamb:.......145 (63C) to 170F (77C)
Pork and ground beef:......160F (71C)
Seafood:...................145F (63C)
Ground fish:...............155F (68C)
Stuffed fish:..............165F (74C)
Other indications that food is cooked include:
Shrimp shells turning red.
Fish flesh becomes opaque.
Clams and mussel shells open then boil for an additional 3 -5 mins.
When reheating food, make sure it is piping hot throughout, do not reheat more than once. Reheated food should be brought to a temperature of at least 165F. (74C)
Do not reheat food in your Bradley Smoker.
Chilling:
http://www.susanminor.org/Rayeimages/food/chilling.jpg
A high proportion of food poisoning events occur because the food has been left at ambient room temperature for too long. If cooked food is to be stored satisfactorily it must be chilled as soon as possible.
When cooling cooked meat cool to less than 7C (45F) within 1.5 to 2 hours.
If ambient temperature is above 90F (30C) reduce this time to 1 hour.
Set the refrigerator temperature to no more than 40F (5C) ….. CHECK!
Set the freezer to no more than 0 F (minus 18C) …… CHECK!
Freeze ground meat, poultry, fish and shellfish if not eaten within two days when stored in a fridge.
Freeze other beef, veal, lamb or pork within three to five days when stored in a fridge.
Use leftovers within three to four days.
Check actual temperatures of fridges and freezers are accurate occasionally using an independent means of measurement.
Do not overcrowd fridge or freezer.
Wrap food carefully.
Check for mold or other signs of spoilage.
Putting food into smaller portions will aid cooling and freezing. Consider investing in a vacuum sealer for long term storage of food.
Do not thaw frozen food at room temperature, it must be moved to the fridge to thaw or defrosted submerged in cold water (change every 30 minutes) or under cold running water.
If defrosting food in a microwave, cook food immediately as a degree of cooking usually occurs when this method of defrosting is used.
Do not place partially defrosted food in the Bradley Smoker; it must be fully defrosted before being placed in the smoker.
Marinate meat and poultry in a refrigerator, NOT at room temperature.
Cross Contamination:
http://www.susanminor.org/Rayeimages/food/toliet.jpg
This is generally the transfer of bacteria from one food (usually raw) to other foods. (often cooked)
It may be direct when one food comes into contact with another or indirect contact from hands, utensils or work surfaces.
To prevent cross contamination:
Wash hands regularly.
Keep raw and cooked food totally separate.
Ensure juices do not leak and spoil other food, store raw meat on the bottom shelf of the refrigerator. Consider using sealed containers for raw meat products.
Use a different chopping board for raw and cooked food.
Clean knives and other utensils thoroughly.
If re-using marinade previously used for raw meat or poultry it MUST be boiled first for at least 3 minutes to destroy bacteria. Ideally reserve a separate portion for use during smoking or as a sauce. The acid in marinade does not kill bacteria; it merely slows or stops bacterial growth.
COMMENT: Food hygiene is not rocket science!! Following a few basic rules….. remember the 4C’s…….. becomes second nature and many people will already be implementing food safety measures almost without realizing.
Having confidence in good food hygiene techniques will give people the confidence to experiment with different foods, processes and ideas.
Why not try cold smoking as an alternative to hot smoking? Perhaps some people are reticent about using pork or fish but providing a few simple rules are followed there is no reason to be worried.
And remember, whilst food poisoning is common, serious consequences associated with food poisoning are fortunately very rare. This is NOT a reason to be cavalier in you approach to food hygiene but rather a reminder to get things in perspective.
"Bacteria as potential tools in bio-terrorism, with emphasis on bacterial toxins". (British Journal of Biomedical Science, volume 62, number 1, 2005, p40 – 46) Food Poisoning and Food Hygiene, Hobbs and Roberts, Sixth Edition.
Medical Microbiology, Mims et al.
Principles and Practice of Infectious Diseases, Mandell, Bennett and Dolin. Fourth Edition.
Cold Smoking and Salt Curing Meat, Fish and Game. A.D.Livingston.
Home Smoking and Curing. Keith Erlandson.
http://www.susanminor.org/Rayeimages/food/p1.jpg
Bradleii nsxbillism
http://www.susanminor.org/Rayeimages/food/p2.jpg
Bradleii bsolomonus
Appendix 1:
Checking a thermometer.
Calibration is a process whereby an instrument can be adjusted by checking it against a known standard. If the value of this known standard is not obtained then it indicates that instrument under question should be recalibrated. Some thermometers cannot be recalibrated.
In relation to thermometers there are two methods of checking they are giving accurate readings:
Boiling Point Method:
Bring clean tap water to the boil in a deep pan.
Put the thermometer stem or probe into the boiling water so the sensing area is completely submerged. Take good care not to scald yourself.
Do not let the probe touch the pan bottom or sides.
Wait 30 seconds or until the indicator stops moving.
The thermometer should read 212F, (100C) or the appropriate boiling point for your elevation. (see below)
If it does not fall within an acceptable range (+/- 5F/2C) the thermometer should be recalibrated according to the manufacturer’s instructions, if indeed it can be recalibrated. Not all thermometers can be.
If the thermometer is under warranty it should be returned to the manufacturer.
If the thermometer is inaccurate, is not under warranty and/or cannot be adjusted it should be discarded. Any false reading at the boiling point of water may not be linear; i.e. it could be more (or less) inaccurate at different temperatures.
The boiling point of water is about 1F (0.5C) lower for every 550 feet (168m) above sea level.
Ice Point Method:
Fill a large container with crushed ice, add clean tap water until full.
Put the thermometer stem of probe into the ice water so the sensing area is completely submerged.
Do not let the stem of probe touch the sides of the container.
Wait 30 seconds or until the thermometer indicator stops moving.
The thermometer should read 32F (0C).
If it does not fall within an acceptable range (+/- 5F/2C) the thermometer should be recalibrated according to the manufacturer’s instructions, if indeed it can be recalibrated. Not all thermometers can be.
If the thermometer is under warranty it should be returned to the manufacturer.
If the thermometer is inaccurate, is not under warranty and/or cannot be adjusted it should be discarded. Any false reading at the freezing point of water may not be linear; i.e. it could be more (or less) inaccurate at different temperature.
The boiling point method is more likely to be applicable to thermometers used in a Bradley Smoker.
However it is recommended the temperature of fridges and freezers is checked perhaps every 6 months to a year and the ice point method is more applicable to this process. Cheap thermometers (under $20/£10) suitable for this are available at many outlets.
Appendix 2:
Curing/Brining.
Curing or brining food (e.g. fish) may have an important role to play in inhibiting bacterial growth.
Cold smoked fish is typically brined at around 80% brine strength.
Brine Strengths (water temperature about 60F).
http://www.susanminor.org/Rayeimages/food/pchart.png
NOTE:
For those interested in the whys and wherefors of Curing and Brining, please see the following article:
CURING and BRINING, From JJC (http://www.susanminor.org/forums/showthread.php?p=21#post21)
1 US gallon = 0.83 Imperial Gallons. Multiply right hand column by 0.83 to get pounds of salt per American gallon.
HAPPY SMOKING……………………………………………
References:
Centers for Disease Control and Prevention (http://www.cdc.gov/)
NHS Direct - U.K. (http://www.nhsdirect.nhs.uk/)
Fact_Sheets/Smoking_Meat_and_Poultry; USDA (http://www.fsis.usda.gov/Fact_Sheets/Smoking_Meat_and_Poultry/index.asp)
Cleanliness Helps Prevent Foodborne Illness; USDA (http://www.fsis.usda.gov/Fact_Sheets/Cleanliness_Helps_Prevent_Foodborne_Illness/index.asp)
Least Wanted Foodborne Pathogens; Fight Bac (http://www.fightbac.org/content/view/14/21/)
National Restaurant Association Educational Foundation (http://www.nraef.org/)
Food Standards Agency - U.K. (http://www.food.gov.uk/)]
Alaskan Cooperative Extension (http://www.uaf.edu/ces/hhfd/)
Smoking Seafood - 3men.com (http://www.3men.com/history.htm)
Mayo Clinic (http://www.mayoclinic.com/health/DiseasesIndex/DiseasesIndex)
Why is it unsafe to marinate foods at room temperature?; FDA (http://www.cfsan.fda.gov/~dms/qa-prp5.html)
What is the first rule of safe food preparation in the home?; FDA (http://www.cfsan.fda.gov/~dms/qa-prp6.html)
What is the second rule of safe food preparation in the home?; FDA (http://www.cfsan.fda.gov/~dms/qa-prp7.html)
Slow Cookers and Food Safety; USDA (http://www.fsis.usda.gov/Fact_Sheets/Focus_On_Slow_Cooker_Safety/index.asp)
NB: this article is for personal interest and information only; it is not meant to be used for self diagnosis, treatment or commercial purposes.
Part 2: FOOD HYGIENE.
Introduction:
"It must be something I ate" is a common explanation given by people to explain a bout of acute diarrhoea or some other gastrointestinal upset. In many cases this will an accurate diagnosis".
In Part 1:
Food Poisoning, it was stated that there are an estimated 76 million cases of food poisoning in the United States every year and around 5 million in the United Kingdom.
The prime cause is bacterial but viral or parasitic infections are not uncommon. Bacteria highlighted included Salmonella, E.coli 0157:H7, Clostridium botulinum, Clostridium perfingens, Shigella and the most common; Campylobacter.
Viruses included hepatitisA and Norwalk like virus whilst parasites included Giardia lamblia and Crytoposporidium parvum.
The first section was primarily about the causes of Food Poisoning whilst here in Part 2 we look at ways of preventing Food Poisoning….. i.e. Food Hygiene.
The vast majority of food poisoning cases are minor but consider this:
Unlike Food Poisoning cases per se, most cases of Clostridium Botulinum poisoning occur in home-prepared food. Botulinum toxin is 15,000 more toxic than VX nerve gas! Botulinum toxin is 100,000 more toxic than sarin!
The threat of bacteria and their toxins as a tool for bio-terrorism is very real (e.g anthrax); it is unlikely they would cause significant mortality (death) but they could cause significant morbidity (disease) and have already caused widespread panic. This gives some idea of the potential potency of bacteria and their toxins.
Some additional Food Poisoning and Food Hygiene facts.
Pathogenic (harmful) bacteria grow best in the temperature range 59 - 113F (15 - 45C) except for Campylobacter which grows well up to 117F. (47C)
The optimum temperature for bacterial growth is 98.6F/37C which is human body temperature, apart from Campylobacter which has an optimum temperature of 107F/42C. This explains why Campylobacter is commonly associated with food poisoning from poultry; birds (avians) have a slightly higher ambient body temperature than humans at around 107F/42C.
This fact is utilized by Microbiology Laboratories; they isolate most bacteria at 98.6F/37C but isolate Campylobacter in incubators set at 107F/42F.
Bacteria divide every 15 - 30 minutes at optimum temp. (98.6F/37C)
Bacteria grow slowly at 113-122F (45-50C), but growth rate falls rapidly above 113F (45C)
Only a few bacteria can grow at more than 122F/50C.
However, the "danger zone"where harmful bacteria can multiply is almost always quoted as 40–140F. (5–60C) This is the temperature range to remember and food must not be allowed to linger in this zone.
Non sporing cells of food poisoning bacteria are killed at temperatures greater than 140F (60C) after exposure for 10 to 30 minutes or more, dependant on bacterial type.
The longer the exposure to high temperatures the higher the degree of bacterial destruction.
At lower temperatures bacteria growth is reduced.
At 45F (7C) bacteria virtually cease to multiply but do not die.
Extreme cold (freezing) does not kill the majority of bacteria.
Extreme cold (freezing) does not kill most viruses, but it does kill many parasites.
Food poisoning can occur when large numbers of bacteria (or spores), viruses or parasites survive, either directly (e.g. bacteria themselves) or indirectly (toxin production) and are ingested.
Bacteria that cause food poisoning will be invisible, the appearance, smell and taste of the food is generally unaltered.
Smoking will only preserve the outside of the meat, not the inside, from bacterial contamination.
Meats that are rolled (e.g brisket) carry additional risk and may be contaminated by handling then rolling the contamination to centre of the meat. Subsequent internal cooking temperature may then not meet that required to kill this bacterial contamination.
Ground meat carries a higher risk of Food Poisoning.
And remember; think of that single bacterium at time zero, under optimum conditions 7 hours later you will have 2,097,152 of the little blighters. But at two hours at optimum temperature that number is only 64.
So, what can be done to significantly reduce the risk of food poisoning.....?
Given that 97% of food poisoning cases are thought to be due to poor food hygiene the answer to this question is.....a lot!!
Food hygiene:
Curing and Smoking food. Foods have been preserved by smoke-curing for many hundreds of years, however it is important to make the distinction between smoking for preservation and smoking for texture and flavour.
Historically food was smoke-cured for preservation and the curing and smoking process were a lot more heavily applied than they are in the present day, when smoking is more concerned with texture and flavour.
Drying (curing) was of paramount importance because moisture is one of the prime prerequisites for bacterial growth. Salt accelerates the removal of water and hence retards bacterial growth.
Smoke (phenols etc) worked in tandem with drying by retarding the development of spoilage bacteria.
Because smoke-cured products nowadays tend to be a lot more mildly smoked and dried, in many instances these processes are not as effective as yesteryear with regards to prevention of spoilage by food poisoning agents. However, some protection will be imparted.
See appendix 2 for brine strength for use in the curing process.
Hot Smoking:
In essence the food is cooked and smoked at the same time with food typically being heated to an internal temperature of 145F (63C) or more, high enough to kill bacteria.
Hot smoking is a lot more tolerant of variations in temperature than cold smoking.
This is the predominant method of smoking in the United States.
Cold Smoking:
The food is smoked but NOT cooked, typically at temperatures of around 60F (15C) with a range of 50-85F (10–29C). However, some sources quote the ideal temperature as being 75-80F. (24-26C). True cold smoking temperature must not exceed 85F. (29C).
There is not really a lower cut off temperature for cold smoking and it is possible to cold smoke at significantly lower temperatures than the literature suggests. However, it does take longer to cold smoke satisfactorily at lower temperatures.
Cold smoking temperatures are not high enough to kill bacteria and correct food handling is essential if this method of smoking is utilized.
If a cooked product is required, food must be (separately) cooked adequately in addition to cold smoking. Cold smoking is more common in Europe.
Some cold smoked products are eaten raw (e.g Salmon) whilst others are cooked. (e.g. kippers – cold smoked herring)
In some parts of the world temperature and humidity may make cold smoking impossible.
The curing and smoking processes involved during cold smoking may inhibit bacterial growth.
Bradley Smoker as a Slow Cooker. The term "low and slow" is often used with regards to the Bradley Smoker; in effect the Bradley Smoker is a slow cooker.
The temperature typically associated with use of the Bradley Smoker is similar to that generally more universally accepted for slow cooking. (170F/70C to 280F/125C)
One major benefit is that less expensive cuts of meat can be used which still become tender and tasty as they slow cook.
It has been shown experimentally that slow cooking is a safe means of cooking with no more inherent risk than other means of cooking provided basic food hygiene standards are maintained.
The main potential problem specifically associated with "slow" cooking is: Power out: electrical or smoker failure:
Whilst food is cooking and once it’s done, food will stay safe as long as the cooker is operating at the correct temperature.
However, if no-one is at home during the entire "slow cooking" process and the power goes out for some reason and you are not sure exactly when, the food should be discarded even if it "looks" done.
If you are at home, finish cooking immediately by some other means. (eg gas grill, barbecue etc.)
Food should remain safe for up to two hours in the event of a power off/out incident.
There is not a specific risk associated with use of a Bradley Smoker in relation to Food Poisoning, what risk there is may be deemed universal risk. I.e. they are associated with all forms of food handling and cooking and not specifically a Bradley Smoker.
A couple of other points to ponder:
If modifying your Bradley Smoker to include, for example, a box and tumble dryer hose for use in the John Watkins/Grakka (see Bradley Smoker forum or Recipe Forum) cold smoking method be careful what the box is constructed from. Some materials (e.g. galvanised steel) must not be used and can lead to chemical residue contamination of food.
It is suggested that if you require specific advice in this area or other use of a Bradley Smoker then contact Bradley or post a question on the Bradley Smoker forum.
Read the instruction manual that comes with the Bradley Smoker.
Just as you would keep any other cooking utensil clean, ensure all parts of the Bradley smoker that come into contact with food are kept scrupulously clean. They are all dishwasher safe.
THE FOUR C’s OF FOOD HYGIENE.
First things first……. it is vitally important to buy or otherwise acquire good quality meat, poultry and fish from a reputable source.
Poor quality produce coming in to a particular food process will equate to poor quality produce out and may increase the risk of food poisoning.
No amount of smoking or curing can make a poor quality product into a good quality one!!
Ask yourself……… are you confident the food has been handled correctly before you acquired it!?
There are four simple headings to remember for good food hygiene, the best reference in my opinion refers to them as the 4C’s………
CLEANLINESS
COOKING
CHILLING
CROSS-CONTAMINATION.
This is sometimes referred to as Clean, Separate, Cook and Chill. (e.g. FightBAC! campaign) but in essence they are the same, 4C’s is easier to remember!!
Cleanliness:
http://www.susanminor.org/Rayeimages/food/shower.jpg
The spread of harmful bugs can be preventing by observing good personal hygiene and keeping work surfaces, utensils etc clean:
The recommended time to wash hands is at least 20 seconds in hot soapy water. Wash both before preparing food and at appropriate stages during the process.
Cover cuts and abrasions, if one becomes infected then stay out of any food preparation area.
Do not handle food if you are ill with a stomach problem, such as diarrhea and/or vomiting.
Keep dishcloths clean, wash regularly….. weekly is recommended.
Use smooth non porous cutting boards made of hard wood or plastic and discard if they become cracked. Wash thoroughly after use using a scrub brush and hot soapy water. (Remember, water must be hot enough to kill the bacteria, at least 140F/60C)
Always wash utensils thoroughly after use, do not mix those used for raw and cooked food.
Food processors or meat grinders must be taken apart and cleaned thoroughly after use, if items are not dishwasher safe then wash manually in hot water.
Use either a commercial kitchen cleaner or 1 teaspoon bleach to 1 quart of soapy water to disinfect work surfaces, sink drains etc.
Cooking:
http://www.susanminor.org/Rayeimages/food/cooking.jpg
Cook food to the proper internal temperature, this varies for different cuts and types of meat.
To ensure meat and poultry are smoked safely; two types of thermometer should be used. One is required to monitor air temperature in the smoker whilst the other is required to determine the internal temperature of the meat, fish or poultry. Some thermometers (e.g. Maverick ET-73) has 2 probes and performs this dual role.
Check the accuracy of thermometers. (See appendix 1)
Typical air temperature of the smoker will be 225F/100C or more when hot smoking.
Cooking times depend on several factors; examples include type of meat and size and baseline temperature of meat at start of cooking. It can take just a couple of hours to 14 hours or more to satisfactorily cook the contents of your smoker.
The recommended internal temperatures to slow cook various types of meat and fish are:
Poultry breast:............170F(77C)
Whole poultry and thighs:..180F (82C)
Ground chicken:............165F (71C)
Beef, veal and lamb:.......145 (63C) to 170F (77C)
Pork and ground beef:......160F (71C)
Seafood:...................145F (63C)
Ground fish:...............155F (68C)
Stuffed fish:..............165F (74C)
Other indications that food is cooked include:
Shrimp shells turning red.
Fish flesh becomes opaque.
Clams and mussel shells open then boil for an additional 3 -5 mins.
When reheating food, make sure it is piping hot throughout, do not reheat more than once. Reheated food should be brought to a temperature of at least 165F. (74C)
Do not reheat food in your Bradley Smoker.
Chilling:
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A high proportion of food poisoning events occur because the food has been left at ambient room temperature for too long. If cooked food is to be stored satisfactorily it must be chilled as soon as possible.
When cooling cooked meat cool to less than 7C (45F) within 1.5 to 2 hours.
If ambient temperature is above 90F (30C) reduce this time to 1 hour.
Set the refrigerator temperature to no more than 40F (5C) ….. CHECK!
Set the freezer to no more than 0 F (minus 18C) …… CHECK!
Freeze ground meat, poultry, fish and shellfish if not eaten within two days when stored in a fridge.
Freeze other beef, veal, lamb or pork within three to five days when stored in a fridge.
Use leftovers within three to four days.
Check actual temperatures of fridges and freezers are accurate occasionally using an independent means of measurement.
Do not overcrowd fridge or freezer.
Wrap food carefully.
Check for mold or other signs of spoilage.
Putting food into smaller portions will aid cooling and freezing. Consider investing in a vacuum sealer for long term storage of food.
Do not thaw frozen food at room temperature, it must be moved to the fridge to thaw or defrosted submerged in cold water (change every 30 minutes) or under cold running water.
If defrosting food in a microwave, cook food immediately as a degree of cooking usually occurs when this method of defrosting is used.
Do not place partially defrosted food in the Bradley Smoker; it must be fully defrosted before being placed in the smoker.
Marinate meat and poultry in a refrigerator, NOT at room temperature.
Cross Contamination:
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This is generally the transfer of bacteria from one food (usually raw) to other foods. (often cooked)
It may be direct when one food comes into contact with another or indirect contact from hands, utensils or work surfaces.
To prevent cross contamination:
Wash hands regularly.
Keep raw and cooked food totally separate.
Ensure juices do not leak and spoil other food, store raw meat on the bottom shelf of the refrigerator. Consider using sealed containers for raw meat products.
Use a different chopping board for raw and cooked food.
Clean knives and other utensils thoroughly.
If re-using marinade previously used for raw meat or poultry it MUST be boiled first for at least 3 minutes to destroy bacteria. Ideally reserve a separate portion for use during smoking or as a sauce. The acid in marinade does not kill bacteria; it merely slows or stops bacterial growth.
COMMENT: Food hygiene is not rocket science!! Following a few basic rules….. remember the 4C’s…….. becomes second nature and many people will already be implementing food safety measures almost without realizing.
Having confidence in good food hygiene techniques will give people the confidence to experiment with different foods, processes and ideas.
Why not try cold smoking as an alternative to hot smoking? Perhaps some people are reticent about using pork or fish but providing a few simple rules are followed there is no reason to be worried.
And remember, whilst food poisoning is common, serious consequences associated with food poisoning are fortunately very rare. This is NOT a reason to be cavalier in you approach to food hygiene but rather a reminder to get things in perspective.
"Bacteria as potential tools in bio-terrorism, with emphasis on bacterial toxins". (British Journal of Biomedical Science, volume 62, number 1, 2005, p40 – 46) Food Poisoning and Food Hygiene, Hobbs and Roberts, Sixth Edition.
Medical Microbiology, Mims et al.
Principles and Practice of Infectious Diseases, Mandell, Bennett and Dolin. Fourth Edition.
Cold Smoking and Salt Curing Meat, Fish and Game. A.D.Livingston.
Home Smoking and Curing. Keith Erlandson.
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Bradleii nsxbillism
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Bradleii bsolomonus
Appendix 1:
Checking a thermometer.
Calibration is a process whereby an instrument can be adjusted by checking it against a known standard. If the value of this known standard is not obtained then it indicates that instrument under question should be recalibrated. Some thermometers cannot be recalibrated.
In relation to thermometers there are two methods of checking they are giving accurate readings:
Boiling Point Method:
Bring clean tap water to the boil in a deep pan.
Put the thermometer stem or probe into the boiling water so the sensing area is completely submerged. Take good care not to scald yourself.
Do not let the probe touch the pan bottom or sides.
Wait 30 seconds or until the indicator stops moving.
The thermometer should read 212F, (100C) or the appropriate boiling point for your elevation. (see below)
If it does not fall within an acceptable range (+/- 5F/2C) the thermometer should be recalibrated according to the manufacturer’s instructions, if indeed it can be recalibrated. Not all thermometers can be.
If the thermometer is under warranty it should be returned to the manufacturer.
If the thermometer is inaccurate, is not under warranty and/or cannot be adjusted it should be discarded. Any false reading at the boiling point of water may not be linear; i.e. it could be more (or less) inaccurate at different temperatures.
The boiling point of water is about 1F (0.5C) lower for every 550 feet (168m) above sea level.
Ice Point Method:
Fill a large container with crushed ice, add clean tap water until full.
Put the thermometer stem of probe into the ice water so the sensing area is completely submerged.
Do not let the stem of probe touch the sides of the container.
Wait 30 seconds or until the thermometer indicator stops moving.
The thermometer should read 32F (0C).
If it does not fall within an acceptable range (+/- 5F/2C) the thermometer should be recalibrated according to the manufacturer’s instructions, if indeed it can be recalibrated. Not all thermometers can be.
If the thermometer is under warranty it should be returned to the manufacturer.
If the thermometer is inaccurate, is not under warranty and/or cannot be adjusted it should be discarded. Any false reading at the freezing point of water may not be linear; i.e. it could be more (or less) inaccurate at different temperature.
The boiling point method is more likely to be applicable to thermometers used in a Bradley Smoker.
However it is recommended the temperature of fridges and freezers is checked perhaps every 6 months to a year and the ice point method is more applicable to this process. Cheap thermometers (under $20/£10) suitable for this are available at many outlets.
Appendix 2:
Curing/Brining.
Curing or brining food (e.g. fish) may have an important role to play in inhibiting bacterial growth.
Cold smoked fish is typically brined at around 80% brine strength.
Brine Strengths (water temperature about 60F).
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NOTE:
For those interested in the whys and wherefors of Curing and Brining, please see the following article:
CURING and BRINING, From JJC (http://www.susanminor.org/forums/showthread.php?p=21#post21)
1 US gallon = 0.83 Imperial Gallons. Multiply right hand column by 0.83 to get pounds of salt per American gallon.
HAPPY SMOKING……………………………………………
References:
Centers for Disease Control and Prevention (http://www.cdc.gov/)
NHS Direct - U.K. (http://www.nhsdirect.nhs.uk/)
Fact_Sheets/Smoking_Meat_and_Poultry; USDA (http://www.fsis.usda.gov/Fact_Sheets/Smoking_Meat_and_Poultry/index.asp)
Cleanliness Helps Prevent Foodborne Illness; USDA (http://www.fsis.usda.gov/Fact_Sheets/Cleanliness_Helps_Prevent_Foodborne_Illness/index.asp)
Least Wanted Foodborne Pathogens; Fight Bac (http://www.fightbac.org/content/view/14/21/)
National Restaurant Association Educational Foundation (http://www.nraef.org/)
Food Standards Agency - U.K. (http://www.food.gov.uk/)]
Alaskan Cooperative Extension (http://www.uaf.edu/ces/hhfd/)
Smoking Seafood - 3men.com (http://www.3men.com/history.htm)
Mayo Clinic (http://www.mayoclinic.com/health/DiseasesIndex/DiseasesIndex)
Why is it unsafe to marinate foods at room temperature?; FDA (http://www.cfsan.fda.gov/~dms/qa-prp5.html)
What is the first rule of safe food preparation in the home?; FDA (http://www.cfsan.fda.gov/~dms/qa-prp6.html)
What is the second rule of safe food preparation in the home?; FDA (http://www.cfsan.fda.gov/~dms/qa-prp7.html)
Slow Cookers and Food Safety; USDA (http://www.fsis.usda.gov/Fact_Sheets/Focus_On_Slow_Cooker_Safety/index.asp)