Food Protection Connection: Food Safety - We Have Always Done it That Way

(reprinted from Dietary Manager, January 2011)

 Much has changed in the past 25 years with regards to food safety . Our ability to identify, track, and confirm foodborne illness has dramatically improved. The science, technology, equipment, and testing to support these investigations have significantly progressed.  Inter-agency cooperation between federal, state, and local health officials has strengthened.  More scientific studies to learn about foodborne pathogens and how to control them have been published.  Who would have thought 25 or more years ago that we could use Pulse-Field Gel Electrophoresis (PFGE) to match a specific strain of E. coli on the East Coast to a strain on the West Coast, and prove that the two pathogens arose from the same source of contamination? It is a daunting task, but it can be done. Technology is changing, and so must foodservice managers and workers.

Our food supply is more globalized than ever before. In the past, we grew, processed, and served our food in a small geographic area. Now, food is grown in one country, processed in another country, and served in yet another country. The more globalized our food supply gets, the more attentive to food safety and food security we must be.  It was not too long ago that the average person did not think of Agro-terrorism or threats to our food supply.  Now, it is one of our nation’s biggest concerns.

The cost to be in the food business has increased. With sick customers comes a bad reputation, followed by potential lawsuits and financial loss. Protecting your consumer’s health is your legal responsibility. Consumers do not expect to eat foods that will make them sick; hence the foodservice worker must have knowledge of how to keep that from happening.

To understand food safety, we first and foremost need to go back to the basics— understanding our food and the pathogens that make us sick. We need to understand WHY we do the things we do in food service, and why food safety regulations include certain constraints. It wasn’t long ago my grandmother told me as a child that we HAD to leave the chicken corn soup on the counter to cool for a long time, otherwise it would ‘sour’.  I wonder now how I ever survived.

There is a public health reason for every food safety regulatory requirement. Understanding your food is the first step. Foodservice employees need to be trained in the “whys” of food safety. As a young regulator, it didn’t take me long to figure out that if I explained why something was a violation, I got better compliance with my facilities. Foodservice employees need to have “buy-in.” When they understand why they are doing a certain task, they begin to change their bad food safety habits. Knowledge is power. Food employees will feel good about what they are doing every day if they understand the impact and importance of their work.

Does the foodservice employee understand the food they are working with? Is the food a Potentially Hazardous Food (PHF) or Time/Temperature Controlled for Safety Food (TCS)? Both terms mean the same thing: food that is capable of supporting the rapid and progressive growth of infectious or toxogenic microorganisms, and that require time/temperature control for safety to limit pathogenic microorganisms’ growth and toxin formation (FDA Model Food Code, 2009). We have grown to know such TCS foods as including dairy, meat, poultry, eggs, and shellfish. In some cases, foodborne illness investigations have shown us that certain foods we never would have suspected are actually TCS foods. These include seed sprouts, cut melons, cut tomatoes, and now cut leafy greens. It is not always easy in a world of growing culinary specialties to determine if a food is a TCS food or not. Occasionally food must be tested for pH and water activity to determine if it is a TCS food.

Is your food a ready-to-eat (RTE) food? If a food is RTE, it’s edible without washing and/or is not subject to a further pathogenic kill step, such as cooking. When dealing with RTE foods, a different set of concerns comes into play, including employee hygiene and equipment cleanliness. It’s not just raw foods that can make us sick. Excellent hand-washing and no-bare-hand-contact with RTE foods is critical within a food facility. According to FDA, “infected food employees are the source of contamination in approximately one in five foodborne outbreaks reported in the United States.” Many people are shedders or carriers of pathogenic organisms. Having good hand hygiene and a strict no-bare­hand-contact policy can be critical. FDA reports in their 2010 Trend Analysis of Retail Food Facilities, that poor personal hygiene (including handwashing) and contaminated food contact surfaces/equipment remain two of the three leading risk factors in need of improvement.

In addition, if a food is RTE, be sure you are not contaminating it by contact with unclean equipment/surfaces. Even the smallest particle of food residue on a piece of equipment can cause a large number of people to become ill. When working with RTE foods, a food employee needs to have an acute awareness of what conditions may recontaminate the foods they are handling. Just because it is cooked or processed does not mean it is safe. It is the job of the food employee to make sure it remains safe.

What is the dietary makeup of your food item? Is it high in protein or carbohydrates? Microorganisms love protein and carbs. They are great sources of nutrients. These nutrient-rich foods need to be handled and processed in a way to reduce risk factors and assure pathogenic microorganisms have been eliminated or significantly reduced.

Is foodborne illness preventable? We will probably never eliminate foodborne illness, but we can reduce the number of outbreaks we have. As mentioned above, it starts with understanding the food and continues with understanding what causes foodborne illness in the first place. Foodborne illness is categorized into three basic groups: Chemical, Biological, and Physical Hazards. Physical hazards tend to be easier to identify, as the naked eye can usually detect them—the piece of plastic, the false fingernail, or the band aid. It is the chemical and biological hazards that are most concerning, and therefore we will focus on these two categories.

CHEMICAL HAZARDS:
Chemical hazards might include the use of detergents, sanitizers, pesticides, medications, natural food additives over their use limits, and naturally occurring toxins into a food item. With today’s technology, these contaminations are not very difficult to identify if they occur. Through chemical analysis, we can detect the contaminant. no one wants this kind of foodborne illness to happen to anyone, therefore make sure that chemicals are kept in such a way that they do not contaminate our food supply and use only acceptable levels of approved chemicals—such as MSg or Sulfiting agents.

Not all chemical hazards are caused by the physical storage and contamination of a food by a chemical stored and used in the food facility. There are naturally occurring toxins such as Botulinum (associated with low oxygen environments), Scombrotoxin (associated with fish), or Mycotoxins (molds associated with grains) that are naturally produced if the food is not correctly processed, handled, or stored. Some pathogens, under the right conditions, will form toxins that can make someone very ill or even cause death in a very short period of time. no amount of cooking will destroy these toxins once formed. They are a chemical hazard once formed. Understanding and controlling these toxins (and foodborne illness) goes back to understanding the microorganism that created the problem in the first place—which bring us to the Biological Hazards category.

Biological Hazards
You do not need to be a microbiologist to understand the basics of what makes microorganisms grow and thrive. Understanding what makes a microorganism live and grow can be summed up with the acronym: “FATTOM” (food, acidity, time, temperature, oxygen, and moisture).

Microorganisms need food. They thrive on protein and carbohydrates. As long as there are nutrients available, microorganisms can potentially grow. Understanding your food’s nutrient content will make you aware whether your food will be a good nutrient source for a microorganism. If microorganisms do not have food, they will not survive and grow.

“pH” is a measure of acidity. A pH of 7 is neutral, 0 is very acidic, and 14 is highly basic. Most pathogens generally thrive between 4.6 and 7. The magic number you will often see is pH 4.6 or below as being the cutoff line. Below this level, foods are not considered potentially hazardous or capable of supporting the growth of microorganisms. Although that is not completely set in stone, it’s a good basic marker for understanding foods. For example, a lemon has an average pH of 2.0. The pH of raw chicken is between 5.5 -6.4. Hence, pathogens are much less likely to grow on a lemon, but may thrive on a piece of raw chicken. Therefore, controlling the acidity of the food item will control the microorganism’s ability to grow and survive. If you cannot control the acidity, then be aware there may be risk factors associated with this food item.

Microorganisms need time to grow to unsafe levels. Bacteria do not begin to grow immediately after getting into food. They need time to acclimate to the nutrients in their new habitat (lag phase). They need time to look around and say “hmmm, yeah, I can live here.” Once they start growing, watch out. if the conditions are right, 1 bacterium may become 68 billion bacteria within 12 hours. Bacteria grow exponentially, doubling every 20 minutes. This is why we have time critical limits for TCS foods. Having time controls within a food facility is vital. Time in the danger zone, cooking time, and reheating time all need to be restricted. If not controlled, within a short period of time, big trouble could be brewing. Why? Because bacteria grow fast.

Time is very closely associated with temperature. Time within the danger zone is a critical risk factor for foodborne illness. The danger zone is 41˚ to 135˚. Every organism has an optimum temperature for growth. Most foodborne pathogens thrive in the danger zone and can grow to unacceptable levels. Limiting time in the danger zone during preparation or improperly hot/cold holding will encourage microbial growth. If there are pathogenic bacteria in food and the food is in the danger zone, after about 4 hours (approximate lag time) the bacteria will begin to grow exponentially.

Don’t think, however, that just because ‘hot food is hot’ and ‘cold food is cold’ and it was not in the danger zone, that problems may not be still brewing. Some pathogens— such as Listeria monocytogenes—can thrive in much cooler temperatures, so sanitation of the actual food product is key, because refrigerator temperatures will not be a control method for Listeria. Knowing the pathogen of concern for your food product will help you decide what temperature control will work best for that particular food and its associated pathogen.

Oxygen level will affect microbial growth. Many bacteria must have oxygen present in order to grow (aerobic). Some grow in the absence of oxygen (anaerobic). There are some that can even grow with or without oxygen (facultative anaerobe). Clostridium botulinum spores (a survival capsule) can develop in no oxygen environments. It will then sit dormant until it has an ideal environment and then start to grow again. This is why there are very specific requirements for canneries, thermal processing facilities, and vacuum packing operations. Understand that if you alter the oxygen levels that a food product is processed, packaged, or stored in, you may create a very dangerous environment, as is the case with C. botulinum.

Moisture is the last component of FATTOM. All microorganisms need moisture to grow. This is measured by “available water” or Aw. Generally if a product is dry, Aw below .86, there won’t be enough moisture available for microbes to use. Additionally, if salt or sugar is added to a product, it will bind to the water and therefore make free water unavailable for use by microbes. Starving microbes of moisture will, in essence, not allow them to grow to unacceptable levels.

Summing it Up
Can you prevent a foodborne illness? Absolutely! The needs of microorganisms must be managed so they do not promote growth. Once you understand your food and understand how microorganisms thrive and grow, you are part way there. Keeping these things in mind and having control measures in place the entire way through the food flow, you get even closer. You need to have control over the food, the time, the temperature, the oxygen, and the moisture at all times. Most of all, the foodservice employee needs to understand the ‘why’s’ of food safety. Once they are empowered with answers and understanding, you should be able to win the battle against foodborne illness. We just simply know more today. The food employee needs to understand we don’t do things like our grandparents did; but they need to know why. You may have always done it that way, but it is time to change and this is why…

by Melissa Vaccaro, MS, CHO
Melissa Vaccaro, MS, CHO is a Food Program Specialist for the PA Department of Agriculture and an Executive Board Member for the Central Atlantic States Association of Food Drug Officials (CASA). Contact her at mvaccaro@state.pa.us.