Risk Assessment for Food Safety – II

Growing Concerns of Food Safety 

As a further consequence, the safety of our food is being increasingly scrutinized and questioned by the public, as food-borne illnesses are significant, costly, and a global problem. There continue to be differences of opinion on how to improve food safety, where industry lacks an integrated and holistic strategy for implementation of food safety in developed world as well as much of the world. Even though, we acknowledge some success in controlling and ameliorating food-borne illnesses and food contamination, these achievements are uneven, often transitory, and especially difficult. Ensuring a safe food supply will likely demand new levels of collaboration, understanding, and thinking. The application of potential solutions is to be viewed and delivered more holistically and with an emphasis on prevention is a compelling and timely strategy.

Thus continuing from the last week’s stop, it is basically needs following segments for better understanding of the subject. However, risk assessments are basically carryout for other requirements are slightly deviated from other assessments, i.e. risk assessment for ISO 9001:2015 due to the importance of food safety hazards which bit different in nature and complex in assessment. Sometimes, risk assessments lead to change composition of the food or way it was prepared due to the risk assessment’s outcome. Thus following topics are necessary to understand in-depth to better cater with continuously upgrading dynamics of food safety in the market.   

Hazard Identification

For each of the hazard: product pairings you identified in a table, you now look for:

Links with confirmed food-borne illnesses both in your country and in importing countries; search the published literature and any national health statistics;

International food-borne disease outbreaks;

Recalls monitored by food authorities in importing countries.

When you put all this information together you will have some idea of the food safety relevance of the hazard: product pairing. At this stage you will be in a position to verify whether a particular hazard: product pairing is sufficiently important to remain in the risk profile. If it has not caused any problems, then you can use your resources more accurately on other pairings. For example, you may decide not to include parasitic worms in your risk profile because all finfish you export are frozen fillets and freezing kills the parasites. In other words, there are critical control points (freezing and frozen storage) that eliminate the hazard and, with it, the risk. This will get you started on your risk profiles but you should update the information by searching the sources recommended above.

Hazard Characterization

Hazard characterization is composed of inter-relationships, which are summarized in this simple diagram

The three main areas for consideration – the pathogen/toxin, the host and the food matrix – all combine to make hazard characterization a very complex part of risk assessment. The simplest way of thinking about hazard characterization is to consider what happens whenever there is large-scale food poisoning. In general, only a proportion of consumers become ill, of whom a much smaller proportion may die.

Why doesn't everyone become ill and why do not all those affected die? The reasons are many and complex.

Exposure Assessment

For any component in our diet, exposure to a disease-causing agent (toxin or microorganism) in that component depends on three factors:

The level of the agent in the meal;

The amount we eat (serving size);

The frequency with which people consume that component.

Comparisons show a 500-times difference in potential exposure, based only on mass consumed. In fact, assessing exposure is rather more complicated because there are usually a large number of other factors to consider such as:

Frequency of contamination (prevalence) with toxin or pathogen;

Changes in level of contamination through the marketing chain;

Seasonal effects;

Consumption patterns;

Susceptibility of consumer;

Preparation effects.

There are examples of how to do the work needed under exposure assessment. This is the part of a risk assessment where you need to do much investigative work. The better the exposure assessment, the more valid will be your risk estimate. Availability of local data is very important for exposure assessment.

Risk Characterization

Risk characterizations use statistics to determine which hazard pose the highest risks. The numerical results represent an estimated probability, similar to the probability of a coin landing heads up (a one in two chance). The numbers help scientists and regulators, but the size and scale are often hard to relate to everyday life, while these numbers are slightly different from risk estimates, they add perspective to the scale of the risk numbers. On the other hand, personal habits and other factors can influence a person's actual risk.

In risk characterization, all previous information from hazard identification, exposure assessment and hazard characterization are brought together to give a picture of the risk. The picture is an estimate of how many people become ill, and how seriously ill they become, if a specific pathogen is in the product. This is called the risk estimate. If a qualitative risk assessment has been done, the risk estimate will be a simple statement that the risk is high or low or medium. If it is a quantitative risk assessment, the risk estimate will be a number, such as predicted illnesses per annum in the population, or the probability of becoming ill from eating a serving of the product. Do not forget that the main reason for doing risk assessments is so that risk managers can use the output – the risk estimates in the characterization. Therefore, the managers need to know whether there is uncertainty and variability in your estimate.

A good example of the effect these two properties are shown by the Lindqvist and Westöö (2000) study on smoked and gravid trout in Sweden. They estimated the number of annual cases by two dose response models. Method one predicted a mean of 168 cases and a range of 47–2 800 cases. Method two predicted a mean of 95 000 cases with a range of 34 000–1 600 000. The ranges reflect the uncertainty built into the predictions, and the authors list the data that should be collected to make more accurate predictions. Another output in the risk characterization that is invaluable for risk managers is a sensitivity analysis. This analysis ranks the influence that each parameter has on the risk. Some factors increase the likelihood of occurrence of illness while others decrease it. Lindqvist and Westöö found that the probability of becoming ill after eating smoked or gravid fish was most affected by:

            Level of contamination (number of L. monocytogenes on the product);

Prevalence of contamination (percentage of servings contaminated);

Serving size (the more you eat the more likely you are to become ill);

Proportion of virulent strains of L. monocytogenes.

These findings help the risk manager to focus on areas that should receive priority action. If the assessors identify uncertainty within these areas, the managers may decide to invest in studies to obtain better data and reduce the uncertainty.

Some risk assessments present the sensitivity analysis as a chart with bars representing the extent of the impact each parameter has on risk. A typical chart is shown below, and because of its shape it is usually called a “Tornado chart”; each bar refers to a particular property that is correlated either with increased or decreased risk.

Accuracy of Risk Estimates

Due to variables and unknown factors, it is impossible to accurately estimate risk. When available, data from human exposure is used to estimate risk. But in many cases, scientists do not have all of the details on actual exposures or how a hazard harms human health, where dose-response factors, or toxicity, are based on studies done on animals or cells, not actual human exposure are used. Furthermore, risk estimations sometimes use computer models to calculate the effects of hazard exposure when actual studies are not available. On the other hand, results between different studies are not always consistent. When this happens, you need to choose the most accurate and health-protective study, but you never should underestimate the real risk.

Reality check

Whether you do a qualitative or quantitative risk assessment you must do a reality check and compare your predictions of annual illness with statistics kept by country’s Health Department.

Risk Assessment for Food Safety - I

Food Safety Systems and Risk Assessment

The most rudimentary processes that historically have been used to preserve foods have also been used to keep foods safe where general principles of heating, cooking, drying, cooling and salting that were reveled thousands of years ago are still the methods by which food safety can be managed in the most basic of settings. As food businesses and their customer base grew larger, distanced by both space and time needs for food manufacturers to consider preservation as a means of maintaining quality products has led to the evolution of modern food safety systems and their accompanying programs. In today’s international marketplace acceptable standards for food safety that use a common language and achieve quality standards of practice are the goals that food safety practitioners focus their attention upon. Considering the context of food safety, assessment of risk and mitigation of risk are the most important part of food safety management systems available. All the HACCP based food safety management systems apply risk assessment as the key criteria to finalize critical control points where prevention and mitigation is taking place to safeguard consumers from the food safety hazards.

The definition of risk is the "possibility of suffering harm or loss; danger" as to the dictionary where scientists use the term risk when assessing potential human health threats from exposure to chemicals or pollutants in the environment. Risk is equal to a person's exposure multiplied by the toxicity of the chemical where exposure is a combination of the concentration of the chemical; a person is exposed to and the length of time they are exposed to that chemical. Toxicity is a measure of the degree to which something is poisonous and is often expressed as a dose-response relationship. Almost every substance is toxic at some dosage, which means; anything in a large enough quantity can be poisonous. For example, an adult ingesting half a cup (400 grams) of salt can be fatal, not only that even water, if consumed in large quantities that can be fatal.

The risks from the foods are also assessed in the same way, but process of risk assessment can be explained as a continuous event, which follows the following order while it practiced. Thus you need to reconsider your risk assessments time to time and consider if there are any new risks has been exposed to the product after initial assessment is conducted.

Estimation of Risks

Estimating risk is a complicated process which involves taking data and multiplying it by a risk factor to determine the likelihood of a health effect. The data must be collected using methods approved for risk assessments and must be verified. I.e. take product samples, measures the chemical levels in the samples and determines if the chemical levels pose a risk to human health. The data is then compared to acute thresholds, chronic thresholds and the probability of disease development.

Exposure and Symptoms

However, the measurements used to determine risk can be very confusing because they are made in unfamiliar quantities. For example, when we speak of exposure, measurements such as micrograms per cubic meter (µg/m3) are sometimes used. Micrograms per cubic meter describe the concentrations of chemicals in the environment. Concentrations of chemicals in air are typically measured in units of the mass of chemical (milligrams, micrograms) per volume of air (cubic meter). However, concentrations may also be expressed as parts per million (ppm) or parts per billion (ppb) by applying a conversion factor. The formula to convert a concentration from micrograms per meter cubed to parts per billion is based on the molecular weight of the chemical and is different for each chemical. Also, atmospheric temperature and pressure affect the calculation. Most of the time a standard atmospheric temperature (25 °C) and atmospheric pressure (1 atm) are used.

Some health problems occur very soon after a person is exposed to a hazard. Symptoms or illnesses occurring from short-term exposure are called acute effects. The immediate effects may be minor (i.e. vomiting, nausea, skin allergies, watery eyes, rash, throat irritation) and may go away once a person is no longer exposed to the hazard. However, some acute exposures may cause serious problems, such as damage to the nerve system. Other health problems may not appear unless a person is exposed to a hazard for many years. These effects are a result of long-term exposure and are called chronic effects. The threshold for chronic effects is usually much lower than the threshold for acute effects since hazard can build up in the body over time.

Process Initiation

The first task is called process initiation – getting started on responding to your customers’ requirements. One strategy is to proceed in the following manner.

Stage 1: Assemble a team

As for food safety management system planning, you need a team that covers a range of disciplines:

A food technologist with knowledge of specific processes and products;

A food microbiologist who knows about microbial ecology;

A statistician to assemble and handle data;

A manager to direct the work

As the manager, it is your task to find the specialists needed to undertake the risk assessment work on behalf of the company. In larger countries with a history of product (e.g. Ice Cream/Soft Drinks) exports, this will not be a great problem. In smaller countries, however, we may need help. Together with WHO, FAO and CODEX has prepared a number of texts, which take you to advanced levels in risk assessments.

Stage 2: Survey the industry

Make a survey of all the products you manufacture and the countries to which you export. This is a straightforward task since every nation keep records.

 Stage 3: Survey product-related illness

Do a preliminary study of product-related (e.g. Ice Cream/Soft Drink) illnesses in the country as well as in countries to which you export. This will set the scene for doing a risk profiling exercise.

If your Health Department keeps records of food poisoning incidents, that is a good place to start your survey. You can make a list of Product-related incidents, linking products with hazards (micro-organisms and toxins) and include these hazards: product pairs in the risk profile. In many countries, however, resources are so scarce that keeping statistics is not a high priority so you should spend some time searching and talking to people who would be likely to know of any illnesses caused by consumption. This is purely anecdotal evidence but has some value – therefore make notes of your conversations. The next stage is to look for statistics from customer countries. If you have Internet access, there are a number of Web sites, where information on food poisonings is included.

Once you have gathered data, assemble them into a summary table. A collection of outbreaks of seafood-related illness in the United States and Australia over the period 1990–2000 is an example of the hazards and products involved in those countries.

The data are valuable because they:

Identify the main hazards;

Provide background on what has caused problems in importing countries.

If you look a little more carefully at the data, you can make a list of hazards and products that will shape your risk profiling exercise.

If you look a little more carefully at the data, you can make a list of hazards and products that will shape your risk profiling exercise.

You now have a list that can form the basis of your risk profile. There may be other perceived issues that need to be added to the list. Some countries perceive these as food safety issues and they also become trade issues, so they are important, and you may wish to assemble some information on them.

Stage 4: Do a risk profile

If you do a risk profile of the industry as a whole this will give you a focus on products and pathogens of most concern. For the purpose of this document, risk profiling is defined as “a description of a food safety problem and its context developed for the purpose of identifying those elements of a hazard or risk that are relevant to risk management decisions”.

This phase of the work entails gathering data in three areas:

Hazard identification

Hazard characterization

Exposure assessment

Once this is done, you will know which pathogen: product pairings should be investigated as a matter of priority.