How to Start with HACCP- Part 1
Dealing with the Microbes: Bacterial Pathogens
Fundamentally, HACCP is a self-control program that prevents hazards from occurring. It is not an overly complicated system, but it takes some know-how to get it right. Microbiology is probably the biggest hurdle for most people when developing HACCP plans. We cannot all be microbiologists, but without some fundamental knowledge about the micro-world you will be guessing about specific biological hazards, the risks they pose, and the necessary controls. Most professionals can easily recognize chemical and physical hazards in food production, and they too may be critical. However, control of these hazards is common sense-while microbial pathogens require study and analysis.
We are fortunate to have considerable scientific understanding about the causes of foodborne illness. The science of Epidemiology explains to us the health impacts of various foodborne illness agents and provides a method to test theories of disease transmission. Epidemiology is the science that deals with the various factors that contribute to the prevalence of illness or injury in the human population. Epidemiology tells us that there are several major disease causing microbiological agents, and many less frequently occurring but still important pathogens.
Microbiology is the study of microorganisms. This science is continually advancing our knowledge with new techniques to study the micro-world, including- BACTERIA, VIRUSES, PARASITES and FUNGI. Microbiological research reveals a wealth of information about how disease is transmitted through food.
Food Science, an important HACCP discipline, studies the entire range of the attributes and characteristics of foods. It is this science that helps us to understand the qualities of the food itself that increase or decrease risk.
Some leading causes of foodborne illness include:
- INFECTIOUS BACTERIA
- E coli O157:H7 (and similar strains)
- GASTRO INTESTINAL VIRUSES
- Norovirus (and similar strains)
- Hepatitis A
Speaking about biological contamination, a food becomes unsafe when it contains a dangerous microbe in sufficient quantity to cause disease. Not all microbes are dangerous, and the dangerous ones have degrees of severity. We can think of microbes causing illness in basically two ways; either they cause-INFECTION, or they cause illness through poisons they produce in the food itself-INTOXICATION.
But it gets more complicated than this. For example, an infectious bacterium such as Salmonella (over 2000 strains causing human illness) causes disease when it enters the digestive tract and begins to multiply within the human host. Preventing Salmonellosis (the disease) means we cannot allow one Salmonella cell to be in a ready to eat food; yet Salmonella can be in raw meat, without adulterating the meat. This means, eggs, poultry and red meat, will have these bacteria from time to time in varying numbers. A primary goal of HACCP in regards infectious agents is to destroy them, as they are readily killed by heating. However, not every food production process contains an effective, measurable “kill step”, such as cooking or pasteurization.
So sometimes, we have to control Salmonella in other ways. Salmonella will reproduce in many types of foods, meaning the bacteria will divide and increase in number, sometimes to the many millions given ample moisture and favorable time and temperature. Therefore, we often alter potentially hazardous food by adding vinegar or acidic compounds, when we can. We add vinegar (acetic acid) to mayonnaise to make it difficult for Salmonella to multiply; or we maintain it cold. Now if you use a raw egg in your mayonnaise, will the acid content be strong enough to “kill” the pathogen or just keep it from multiplying? This is a good question and one that you must answer if you make mayonnaise yourself. The food processing industry prevents Salmonella in commercial mayonnaise and similar products by pasteurization of the egg and acidification of the mayonnaise; but the restaurant chef may not realize what he is up against with his “homemade mayonnaise”.
Salmonella is also a threat in produce, especially tomatoes and leafy green vegetables due to growing and harvesting risks. Salmonella must be dealt with in another way in vegetables meant to be eaten raw. Sometimes, the best we can do is reducing the bacteria to acceptable levels. The produce industry uses various means of removing contamination, and the washing process in a produce packinghouse can be critical for many produce items. However, washing has some limitations, and operators need detailed knowledge of the antimicrobial quality of the wash water and the disinfection process itself to ensure effective risk reduction.
Well what about that other classification-INTOXICATION? Most people are familiar with the effects of a “few too many”. The result is a buildup of alcohol, a toxin, in the blood. Certain bacteria, some fungi and a few recognized toxic algae have the ability to produce a toxin directly in the food before it is even eaten. When we ingest this toxin, it’s not fun-it’s called “food poisoning”. This is critically important to understand because preventing the buildup of toxins in foods, like preventing Salmonella or other infectious agents, is a primary goal of HACCP.
Luckily, there are relatively few microbes that have the ability to poison our foods. They can do this if they are allowed to multiply. As the result of this growth, toxic by-products accumulate in food (in the case of Clostridium perfringens, the toxin is formed in the intestine). The higher the number of cells, the more likely this is to occur. Viruses emit toxin also, but in the host; many infectious bacteria such as E. coli O157:H7 also produce very damaging toxin in the body, but there is no evidence they can accomplish this in the food itself.
- TOXIGENIC BACTERIA
- Clostridium perfringens
- Clostridium botulinum
- Bacillus cereus
- Staphylococcus aureus
So how does HACCP deal with the problem of bacterial toxins in food? The answer is there are commonly two important methods; through temperature control and through advanced pasteurization techniques. Temperature control is often needed because the toxins produced are heat stable and for the most part cannot be easily denatured by further processing. However, the food processing industry has developed techniques of pasteurization to reduce “preformed-toxin” risk from three spore forming bacteria. As it turns out, Clostridium botulinum, Clostridium perfringens, and Bacillus cereus are spore forming bacteria that can produce toxin in food.
Just like the toxins they produce, the spores themselves are heat resistant, but they can be destroyed at temperatures greatly exceeding 212 F. The canning industry uses a combination high temperatures and various exposure times to ensure a thorough “spore-kill” in a “retorting process”. Once the spores are inactivated, they cannot germinate, or multiply or elaborate toxin (bacterial spores are like tiny seeds that will sprout). The dairy industry uses Ultra High Temperature Pasteurization (UHT) and aseptic packaging to produce shelf stable dairy products, like creamers.
Advanced pasteurization methods will destroy spores, but when this is not possible, temperature control is required; cold or hot temperatures will also work to maintain conditions unfavorable for bacterial spore germination.
Drying food sufficiently (reducing Water Activity) will also create unfavorable conditions for bacteria.
Finally, many processes, formulations and recipes rely on a combination of control measures. These control measure combinations work together to prevent bacterial multiplication and destroy infectious agents.
HACCP Principles Online and Classroom
While our courses cannot make you a microbiologist, we can show you some methods to streamline the hazard analysis to accommodate the various microbial risks in foods. We will show you how to take into account the unique attributes of microbes and the unique nature of production. Furthermore, you will grow in your understanding of HACCP methods as you work through the seven HACCP Principles.