Is Food In My Kitchen a Safety Hazard?

Introduction
Know the Hazards
Handle Those Foods Safely
Shopping
Transporting
Storing
Preparation
Use Cooking Methods Safely
Serving
Leftovers
Glossary

Many consumers and others who handle food on a regular basis seem to take a casual approach to microbiological causes of foodborne illnesses.

The Center for Disease Control in Atlanta, Georgia, estimates that about 250 million Americans every year suffer from bouts with food poisoning bacteria and about 5,000 victims die. The Food & Drug Administration (FDA) has estimated that as many as one in six Americans suffer from some form of food poisoning each year. Estimates vary because many cases of food poisoning from microorganisms go undiagnosed or unreported, as symptoms may be similar to flu.

Diarrhea of foodborne origin is especially prevalent and may account for as many as 81 million cases per year. The economic impact of food-borne disease is staggering, with costs of medical care and lost productivity estimated between 5 and 17 billion dollars annually.

Foodborne illness is a more comprehensive and accurate term than food poisoning. Food poisoning refers more specifically to those illnesses caused by toxins or poisons produced by microorganisms. Ptomaine poisoning was another term used in the past which does not accurately describe illnesses.

Foodborne Illness or Foodborne Disease are terms used when a disease or injury occurs as a result of eating a contaminated food. Contaminated foods are foods in which microorganisms are present and will grow, or foods which merely serve as a carrier for a microbial agent, virus or toxin.

New knowledge and technology have provided us with the means to keep food safe. At the same time other new and modified technologies may introduce additional opportunities for foodborne illness to enter the picture. Some of these concerns are discussed under New Technologies -- New Safety Tips.

Today more causes of foodborne illness have been identified and have become concerns. In 1958 a leading food microbiology textbook listed only three agents of foodborne illness. In recent years means of detecting certain organisms such as campylobacter jejuni, listeria monocytogenes, yersinia enterocolitica, etc. have added many more to the list.

Proper food handling practices in the home can help prevent foodborne illnesses. Homemakers should examine their kitchen environment for hazards and they can do this only if they are aware of foodborne hazards.

A hazard is a source of danger. It is a place where food safety problems can begin if foods are not properly handled.

Know the Hazards

Foods don't cause illness; disease-causing microorganisms (pathogens) do.

All foods are subject to spoilage which may make them undesirable for eating. However, not all foods can cause foodborne illness. For example, an overripe pear is soft, mushy and very unappealing, but it would not be unsafe to eat.

Some microorganisms are used for a desirable change in foods. Yeasts are used in bread and wine making. Certain bacteria are required to make sauerkraut or to sour milk. Molds are a part of ripening of some cheeses.

Foodborne illnesses are caused by pathogenic microorganisms, which include viruses, yeasts, molds and bacteria, including salmonella sp. and staphylococcus aureus. There are also some parasites that can be found in some foods that may be dangerous, as trichinella spiralis.

Certain conditions need to be present before a food can carry a foodborne illness. These conditions, which will be discussed throughout this circular, are:

• The food is a potentially hazardous food.
• Pathogenic (disease-causing) microorganisms need to be present.
• Inappropriate food handling practices are used.
• Time-temperature combinations are such that microorganisms will grow in foods.
• Environmental conditions permit the maintenance and transfer of pathogenic foodborne microorganisms.

Potentially Hazardous Foods

"Potentially hazardous" foods sounds to many of us like something we don't want to eat. In reality, this descriptive phrase has been used for many years by food regulators such as FDA and health departments. Food regulators can require proper refrigeration and cooking for foods which are designated as "potentially hazardous."

As interest and concern about food safety have increased, the designation has appeared in popular papers and magazines. The designation "potentially hazardous food" simply identifies food for which time/temperature management is necessary for safety. For example, an apple pie is not considered a potentially hazardous food because it may be kept at room temperature and remain safe to eat. A banana cream pie, on the other hand, is a potentially hazardous food because it must be kept under refrigeration to maintain its safety.

Potentially hazardous food includes a wide range of perfectly wholesome, nutritious food commonly found in home refrigerators, including most meats, poultry, fish, dairy products, cooked pastas and cooked vegetables. The term does not imply that a food is naturally unhealthful. Rather, it means that the food needs to be stored under proper refrigeration and must be handled and cooked properly to maintain its safety.

Any food which supports or allows the growth of pathogenic microorganisms needs to be handled with special care in order to be kept safe for human consumption. Foods with protein (amino acids), low acidity and high moisture (available water) are likely to support micro-organism growth. (See Table 1.)

Table 1: Characteristics of Foods 
----------------------------------------------
Characteristic	Foods
----------------------------------------------
Protein Foods 	meat, poultry, fish, 
 (Amino Acids)	dairy products, eggs

Low Acid	protein foods listed above 
		vegetables except tomatoes

Moisture
  High 		protein foods listed above 
  (above 40%)	fruits & vegetables

  Intermediate 	soft candies; jams; jellies; 
  (20-40%)	honey; many dried fruits; 
		some bakery items; some meat 
		products such as pepperoni, 
		country ham, jerky and some 
		dried fish 

  Low 		dry milk; dry eggs; flour; 
  (Below 20%)	cereals; dehydrated vegetables 
		and meats
----------------------------------------------

Water in food is one of the most important factors influencing microbial growth. The moisture must be available -- that is, not tied up in any way. Sugars and salts will tie up moisture. This means that the moisture is not available for microorganisms to use for growth. Syrups and honey are examples of foods which appear to have a lot of moisture but do not spoil without refrigeration because their moisture is bound by the high sugar concentration. Another example is catsup, which is high moisture but also contains enough acid to be safe at room temperature.

Certain foods are involved repeatedly in cases of foodborne diseases. Foods that have been identified in the United States as vehicles from 1977-1984 are listed below:

Item                  Number
-------------------------------
Roast Beef             155
Raw Shellfish          128
 (mostly Norwalk-like
  virus illnesses)
Turkey                  86
Chicken                 69
Ham                     65
Pork, Unspecified       57
Mexican-Style Foods     56
 (beans, ground/
  shredded meat)
Chinese Food            51
 (mostly rice)
Potato Salad            41
Rice                    27
Chicken Salad           22
Cream-Filled Pastry     17
Meat Tacos/Enchiladas   14
Shrimp                  14
Macaroni Salad          12
Pizza                   11
Turkey Salad            10
Tuna Salad               9
Ground Meat              9
Barbecue Meat            9
Egg Salad                7
-------------------------------

Surveillance data from        
Centers for Disease Control (Bryan, 1988a). 

These Foods Require Special Care:
Meat, poultry, fish, shellfish, meat-and-seafood salads, potato salad, milk products, eggs, cream pies, custards, eclairs, cream puffs, cake fillings, gravies, cooked pasta, cooked vegetables, mushrooms, rice and refried beans.

Where Do Pathogenic Microorganisms Come From?

Microorganisms are abundant in nature and the cause of most food-borne illness. Bacteria are usually found on all agricultural and fishery products. Another major source of bacteria is people and animals including pets. In essence, the micro-organisms are almost everywhere.

These microorganisms do not increase in size but increase in numbers. Limited numbers in food are not enough to cause illness. Therefore, control lies not only in reducing contamination, but in preventing conditions that would allow micro-organisms to multiply.

Figure 1: Bacteria reproduce by dividing.

Raw foods brought into the kitchen sometimes bring pathogenic microorganisms with them. For example, raw meat and poultry often carry Clostridium perfringens, Staphylococcus aureus and Salmonella bacteria. Eggs, when laid, may harbor salmonellae. Fish, shellfish and marine crustaceans are sometimes contaminated with Vibrio parahaemolyticus. Raw vegetables and spices are often contaminated with C. perfringens and Bacillus cereus.

It is not feasible to eliminate all of these microorganisms. However, when we know they may exist, almost all cases of bacterial foodborne illness can be prevented by proper food handling.

Molds

Molds grow under a wide range of conditions but are most likely to spoil acidic foods like fruits, or low-moisture foods like bread. Under these conditions molds outgrow bacteria.

If there is only a small area of mold on a piece of hard block cheese, hard salami or a dry cured country ham, the food can be salvaged by cutting out an inch of the product surrounding and below the moldy area. Keep the knife out of the mold itself and recover the food in fresh wrap.

Some foods, such as blue cheese, get their flavor from mold growth. Any visible moldy foods that should not have mold growth, such as other cheeses, sour cream, hot dogs, lunch meats, baked chicken, soft fruits and vegetables, bread, cake, flour, rice, peanut butter, jelly, etc., should be discarded. To avoid spreading mold spores, gently wrap the food or place it in a bag before discarding. Be sure to examine other items that the moldy food may have contacted. With hot soapy water clean the refrigerator or the container that held the item.

Some molds produce toxins (poisons) and it's hard to tell which do and which don't. The most toxic molds grow on grains. The visible mold may not be all the mold there is. The thread-like hyphae (the equivalent of roots) may have penetrated the food.

To keep foods from molding:

• Protect fruits and vegetables from damage.
• Wash fruits and vegetables only when you are ready to eat them. This is especially true for berries.
• If larger fruits are washed before storage, dry them well.
• Refrigerate to prevent or slow mold growth.

Handle Those Foods Safely

Most foodborne illnesses result from mishandling of food either in the home or in food service establishments.

There is little or no hazard of food-borne illness for most foods if they are eaten soon after having been cooked. But as the time between cooking and eating increases, temperature control during the interim becomes of greater concern. Preparing foods a day before serving, improper cooking, inadequate reheating and improper hot-holding are usually identified as contributing factors to foodborne illness outbreaks and these are things often done when large groups are fed for the family reunion or a community gathering.

Cooking can destroy natural barriers to contamination in some foods from plant sources and can free up nutrients needed for microorganisms to grow in these foods. Outbreaks of foodborne illness have been associated with bean curd (tofu), corn, lima beans, mushrooms, refried beans, rice, squash and sweet potatoes that were cooked and then held for some time before eating.

Botulism -- The Deadly Toxin

Fortunately, botulism cases are few, but they can be deadly or have long-lasting effects. The Clostridium botulinum bacteria grow in low acid foods (see Table 1) which are in a reduced or an oxygen-free (anaerobic) environment and produce a toxin. It is the toxin that causes the illness.

When foods are canned, a vacuum is formed and the can, jar or package becomes a low-oxygen environment. Therefore, it is important that all C. botulinum spores be destroyed by the heat treatment during processing of low-acid foods so the botulism toxin is not produced. Low-acid foods are listed on Table 1.

Mixing acid and low-acid foods changes the acidity of the product and the canning procedures. The salsas, hot sauces and picante sauces which have become so popular today are mixtures of acid (tomato) and low-acid (green pepper, hot peppers, onion, celery, etc.) ingredients. These are generally eaten without reheating. Caution: These products can be unsafe if they are not properly canned.

Use only tested canning recipes from a reliable source, such as USDA, when home canning these products. Many of these mixtures will require pressure processing to assure safety. These products also can be safely frozen.

Foods which are vacuum packaged, either at home or commercially, are in an oxygen-reduced environment. Many meat products are on the market in vacuum packages. Potentially hazardous products packaged in this manner maintain a high quality for longer periods of time, but must be kept refrigerated and should be used within the recommended time to assure safety. Using home vacuum packaging equipment does not take the place of heat processing foods for preservation.

Food Preservation

Home food preservation can be safe when current, tested recommendations are followed. Consider the following:

• Current recommended processing times should be used.
• All low-acid foods (see Table 1) must be pressure processed, frozen or dried.
• All canned foods need a heat treatment -- that is, pressure processing or hot water bath -- after they are placed in the jars.
• Any unsealed product must be reprocessed, frozen or refrigerated within 24 hours.

It is not safe to assume that all boxed and canned goods may be held at room temperature. Read labels!

Raw Milk Caution

Almost all milk is pasteurized these days. Yet some people still use raw (unpasteurized) milk and should be aware that it can be a food safety hazard.

Pasteurization is a mild heating process that kills pathogenic micro-organisms in milk. There is little effect on the nutrients, only a slight decrease in thiamine, vitamin B12 and vitamin C.

Milk is an excellent vehicle for bacterial infection. While immunization and testing of cows in this country has virtually eradicated many diseases, there are still many avenues by which bacteria, viruses and other microorganisms enter milk. Pasteurization is by far the most reliable safeguard.

Several serious disease outbreaks in recent years have been traced to raw milk or raw milk products. Some of the pathogenic microorganisms involved were campylobacter jejuni, salmonella sp. and listeria monocytogenes.

HACCP

HACCP stands for Hazard Analysis Critical Control Point procedure. Very simply, this system is designed to ensure food safety by reducing the likelihood of foodborne illness. This is accomplished by identifying the places and procedures in which food could become unsafe during food handling, preparation and storage. Then steps are taken to control these points to assure the safety of the food.

This method is gaining in popularity with the food industry and regulatory agencies. As both manager and regulator of your own home food supply, you can use some of these concepts to make and keep eating at home from becoming a safety hazard.

The following tips are provided to help home kitchen managers be aware of items to consider when examining their home food practices for food safety hazards. The articles supply more detail to help increase your understanding of the reasons for some of these tips.

Most food poisoning bacteria are odorless, colorless and tasteless. Therefore, the only sense protecting you against foodborne illness is common sense. If in doubt throw it out!

Shopping

Container Condition

Swollen or dented cans may be an indication that food spoilage has occurred or is possible. The swelling is caused by gases produced by spoiling foods or microorganisms. Dents which occur from handling may affect the seals.

Soiled or torn packages and labels may indicate careless handling, old products, tampering or spoilage. Streaks on containers may indicate leakage at some point. Punctures or broken seals in packaging will allow for outside contamination.

Cross Contamination

Raw meats, poultry and fish, which are safe to eat when properly cooked, can contaminate foods which will be eaten without further cooking. To prevent cross contamination, position packages of raw meat, poultry and fish in your shopping cart so their juices cannot drip on other foods. You may wish to enclose individual packages in plastic bags.

Ask store baggers to keep the raw meats separate from the ready-to-eat foods.

Shopping Tips

• Buy only foods in good condition and with sound packaging.
• Shop just before going home.
• Shop for perishable foods last.
• Buy products labeled Keep Refrigerated only if they are stored in a refrigerated case.
• Buy eggs only from refrigerated cases.
• Buy unpackaged meat or poultry from refrigerated cases in deli only if there has not been contact with other foods.
• Keep refrigerated and frozen items together so they remain cold.
• Buy only foods which can be used before the use-by date.
• Buy only the amount of shaved deli meats that can be used in 1 or 2 days.
• Buy frozen foods that are frozen solid without frost build-up on the package.
• Avoid cross contamination.
• Report problems with packaging, product, storage or sanitation to store management. If you are still unsatisfied, report the problem to local health authorities.

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[ Serving ] [ Leftovers ] [ Glossary ]

HE-492 (Revised), Reviewed December 2006