Introduction
Food plays a major role in fulfilling the biological needs of humans as indicated by Maslow’s hierarchy pyramid. Conventionally, food was made in a home setting where families would enjoy their meals together.
However, recent changes in people’s lifestyles have shifted food preparation activities from homes to outside settings where there is socialization in addition to food consumption. Such settings include food establishments such as restaurants and street hawkers. Also, lifestyle changes have increased the number of people eating food from these establishments. A consequence of this change is the emergence of food-borne diseases because of unhygienic preparation of food (Ismail et al. 2016). Therefore, there is a need to ensure that food is safe for human consumption through food safety.
Food safety is a specialty that describes the right ways to handle, cook, and store food to avoid the transmission of food-related illnesses. An important aspect of food safety is the personal hygiene practices of the food handlers as they make contact with the food. Food safety has become a grave public health concern because of several reasons. For example, the rising trends of lifestyle diseases have raised awareness on the importance of healthy eating.
As a result, the rate of consumption of fresh fruits and vegetables as well as pre-prepared foods has increased significantly. As much as eating these foods is advisable health wise due to their high nutritive value, the preparation of freshly cut salads does not include heat procedures that are crucial to the destruction of germs. Additionally, pre-cooked foods do not allow food to reach temperatures that are sufficiently high to kill disease-causing microorganisms. The increasing popularity of lightly cooked and raw foods such as ‘rare’ burgers and ice-cream also increases the likelihood of food contamination.
Giving food to people comes with a tremendous responsibility. The UK Food Standards Agency (2017) revealed that more than half a million instances of poisoning that occur annually are a consequence of poorly cooked food or the contamination of food by pathogenic bacteria. According to the World Health Organization (WHO), one out of every ten people become sick from consuming contaminated food, which leads to the death of approximately 420,000 people annually (WHO 2016).
Children below the age of five years are highly susceptible to food-borne diseases. Therefore, it is imperative to adhere to high standards of hygiene and the recommended food handling procedures. The human food chain starts from the farm to the point of consumption, which in most cases is already prepared food on the eater’s plate. Contamination of food can take place at any point in the course of production, transportation, storage, and preparation.
Thus, maintaining food safety is the responsibility of every person along the production chain. Upholding high standards of personal hygiene through the washing of hands and using clean kitchen equipment to process food is vital to food safety.
The first purpose of this lab is to compare the effectiveness of different agents used in washing and decontaminating food contact surfaces. The second purpose is to determine the possibility of cooking a safe ‘rare’ burger on the barbeque and determine the shortest time required for the internal temperature of a pattie to reach the minimum cooking temperatures recommended by the WHO.
Results
Rapid (ATP-ase) appraisal of cleaning/sanitizing food contact surface (cutting boards)
It was observed that antibacterial detergent was the most effective cleaning solution with 0 RLUs post-treatment as shown in Table 1. Bleach, on the other hand, was the least effective cleaning agent because the post-treatment RLU measurements were comparatively higher than when other cleaning agents were used. Warm water produced satisfactory results. Scratched plastic recorded relatively higher RLU readings than unscratched and undamaged plastic.
Table 1: Relative Light Units (RLU) Recorded When Different Surfaces Were Cleaned With Various Cleaning Agents.
Burger pattie temperature data
The average temperature data for the burger pattie was plotted against time as shown in Figure 1. It was observed that the starting temperature was approximately 20 oC for the first nine minutes. The temperature dropped to 9 oC by the 20th minute and rose afterward to 27 oC in the 42nd minute. Therefore, the maximum temperature recorded was 27 oC. Another drop in temperature to approximately 15 oC was observed after which the temperature rose and stabilized at 25oC. The burger pattie was hardly cooked and could be described as ‘rare.’
Conclusions
From the results of the cleaning of food contact surfaces, it can be concluded that antibacterial detergents are the most effective in cleaning agents. However, the limitation of the luminometric procedure was the lack of replicate measurements for each surface cleaned using different sanitation agents. Such a procedure would have facilitated statistical analysis to determine whether there was a significant difference in the efficacy of the cleaning agents.
Even though the ATP method provides a rapid and cost-effective way of checking the cleanliness of food contact surfaces, there is a need for more specific methods of assessing food surface hygiene. It was also concluded that it was not possible to cook minced meat to the minimum temperatures recommended by the WHO on a barbeque.
Discussion
The ATP method of quantifying bioluminescence depends on the production of light in the presence of ATP. The chemical reaction involves the oxidative decarboxylation of the compound luciferin in the availability of ATP (Osimani et al. 2014). The enzyme luciferase hastens the rate of this reaction. ATP is a high-energy molecule that is present in food as well as living organisms. In this method, the amount of light emitted is proportional to the quantity of ATP.
The findings of this experiment show that even though cutting surfaces may appear clean to the naked eye, there may be scores of bacteria on the surfaces. Cleaning entails the manual removal of food particles even though it does not guarantee that the surface is sanitary. Therefore, there is a need to sanitize food contact surfaces to eliminate or reduce the numbers of disease-causing microbes (Garden-Robinson 2012).
Nevertheless, sanitizing does not produce a sterile environment as it is practically impossible to attain such standards in food service facilities because of prohibitive sterilization costs. Instead, affordable sanitizing agents can ensure clean food contact surfaces. Different sanitizing agents require varying concentrations, contact time, and operating temperatures for their effectiveness. Studies show that combination products, for example, detergent-sanitizers require separate cleaning and sanitizing steps. Two separate solutions of the same agent should be used for cleaning and sanitizing steps.
Manual cleaning needs to follow five main steps, the first of which is to get rid of large food particles. The next step involves cleaning with an appropriate detergent and water at approximately 45 oC followed by rinsing in clean, hot water. The fourth step involves sanitizing in hot water at about 77 oC for a minimum of 30 seconds (Garden-Robinson 2012). Alternatively, an appropriate chemical sanitizing solution, for example, chlorine, iodine, or quaternary ammonium can be used. However, the right concentrations of these solutions should be made based on the manufacturer’s instructions.
The concentrations of chlorine solutions for the sanitization of food contact surfaces should be 25 parts per million (ppm) at 48 oC, 50 ppm at 37 oC or 100 ppm at 12 oC (Garden-Robinson 2012). On the other hand, iodine solutions for sanitization should have a concentration ranging from 12.5 to 25 ppm at the lowest possible temperature of 23 oC. It was noted that antibacterial detergent was the most effective cleaning solution.
Bleach, on the other hand, was the least effective cleaning agent while warm water produced satisfactory results. The active ingredient in bleach is chlorine, which is among the recommended chemical cleaning agents. However, the precise concentrations of bleach used to clean the cutting board were not specified. There was likelihood that incorrect concentrations of bleach were used to clean the cutting board, which hindered the effectiveness of the solutions.
The effectiveness of cleaning agents at different concentrations is attributed to the impact of the chemicals on the proteins of bacterial cell walls. These chemicals disrupt the structure of bacterial membranes and cell walls, which interferes with crucial life-sustaining processes that lead to the death of bacteria (Srey, Jahid & Ha 2013).
Scratched plastic recorded relatively higher RLU readings than unscratched and undamaged plastic. This observation could be attributed to the formation of crevices on the surface of the cutting board during scratching. These crevices were likely to harbor food residues, thus producing conducive environments for breeding of bacteria. During cleaning, it was relatively difficult for the cleaning agent to remove all the dirt from the crevices hence the corresponding high RLU values recorded.
These observations are consistent with those published by Osimani et al. (2014) showing that nylon chopping boards are not easy to clean. Osimani et al. (2014) attribute the difficulty of cleaning to the porous surfaces that characterize nylon cutting surfaces, which form shallow cuts and cracks that make cleaning difficult. Therefore, higher reference limits are applicable when using the ATP bioluminescence test for cleanliness.
Osimani et al. (2014) reported that the RLU readings per cubic meter for meat cutting boards (made of plastic) measured over an eight-month period increased over time. This observation implied that the progressive wear of the cutting board enhances the formation of crevices, which in turn increases the difficulty of cleaning. ATP bioluminescence has been shown to be effective in the instantaneous monitoring of surface sanitation as well as the authentication of cleaning processes as per the Hazard Analysis Critical Control Point (HACCP) plan recommendations (Garayoa 2016). This technique also acts as an indicator of poor hygiene, thus prompting the required corrective measures, for example, repeated cleaning of dirty surfaces or the replacement of worn work surfaces.
Saad et al. (2013) recommend that food business workers should ensure the safety of food by using simple and cost-effective methods of identifying microbes. However, in a study conducted by Osimani et al. (2014) comparing the ATP readings and viable bacterial cell counts of similar surfaces, it was evident that the sampled considered dirty by the bioluminescence technique did not harbor mesophilic aerobes or coliform.
This finding suggests the low specificity of the ATP-based method. Additionally, these observations show that checking the ATP levels cannot replace the conventional method of measuring the microbial burden of food contact services. As much as the ATP method provides a rapid and cost-effective way of monitoring the cleanliness of food contact surfaces, there is a need for more specific methods of assessing food surface hygiene.
In the minced meat experiment, the starting temperature of approximately 20 oC for the first nine minutes was attributed to the prevailing room temperatures of the temperature logger. The subsequent drop in temperature to 9 oC was because of the temperatures of raw minced meat, which had just thawed. Heat from the barbeque contributed to the ensuing rise in temperature to 27 oC by the 42nd minute. The second drop in temperature to 15 oC was attributed to the temperature of the cold water into which the temperature logger was dropped upon extraction from the burger pattie. The final stabilized temperature of 25 oC was the room temperature after removal of the temperature logger from cold water.
The above findings showed that it was impossible to cook a safe ‘rare’ burger on a barbeque within an hour. The WHO recommends that potentially hazardous foods should be cooked to a minimum internal temperature of 70 oC. However, it was only possible to reach a maximum temperature of 27 oC after 40 minutes.
Bacteria pose the greatest risk to food safety. Their survival requires six main conditions: a source of food, conducive temperatures, acidity, moisture, oxygen and time (Garden-Robinson 2012). Consequently, controlling any of these aspects can curb the growth of bacteria. Of these factors, time and temperature are the easiest for food handlers to handle to prevent food poisoning and food-borne diseases. The most favorable temperatures for bacterial growth range from 5 oC to 57 oC (Garden-Robinson 2012).
These temperatures lead to rapid growth of bacteria with generation times ranging from 10 to 30 minutes. Consequently, a single bacterium can regenerate to thousands of bacteria in three hours. Allowing food to reach the recommended temperatures during cooking and cooling food rapidly are necessary to avoid the contamination of food.
Food handlers can ensure that food cooks to the recommended temperatures by measuring the temperatures of food using clean, sanitized thermometers. Accurate temperatures can be obtained by making sure that the thermometer is placed in the densest section of the food (Sibanyoni, Tshabalala & Tabit 2017). To guarantee the accuracy of thermometers, calibration of thermometers should be done regularly. The recommended method of calibrating a food thermometer involves placing it into a container holding ice and water and changing the reading to 0 oC. Calibrating a food thermometer following exposure to temperature extremes is necessary. The cooking of food should not be interrupted because partial cooking allows bacteria to thrive thus leading to food poisoning (Guinebretière et al. 2013).
Recommendations
Cross-contamination is a known cause of food poisoning because of the transfer of bacteria from one source to another. Therefore, new business owners, hotel managers, and food handlers should be aware of the causes of cross-contamination and how to avoid it.
To new business owners
Business owners should invest in appropriate cleaning agents for their establishments with the most effective cleaning agent being antibacterial detergent. In the absence of antibacterial detergent, warm water should be used alongside other detergents. They should also ensure that their food establishments’ budgets are sufficient to cater for rapid tests for microbial tests on food contact surfaces and other kitchen equipment.
To managers
Managers should ensure that the food handling surfaces are in good condition to ease the cleaning process. Worn out cutting boards should regularly be replaced to reduce the risk of food poisoning. Managers need to conduct regular hygiene monitoring checks to ensure that the food handlers work according to the set standards of food hygiene. According to the Food and Agriculture Organization (FAO), microbial contamination of food continues to happen because of inadequate knowledge and food handling habits (Ismail et al. 2016). Therefore, to promote the adherence of food safety standards, managers should organize for regular food safety education sessions for food handlers in their establishments.
To food handlers
Food handlers should wash food contact surfaces thoroughly and pay more attention to scratched surfaces. Food handlers should have information about the internal temperature-time profiles of different potentially hazardous foods. This information will help them ensure that these foods are cooked for the minimum time required to prevent instances of food poisoning. Food thermometers should be used to ascertain the cooking temperatures of potentially hazardous foods. Also, regular calibration of the thermometers is necessary to guarantee the accuracy of the thermometers.
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