Food Safety Micro Bio Lab report (1) (1)

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Food Safety Lab Report Danielle Pasternak Nov 26, 2023 10:49 PM Performed At Home BIOL 1020L Microbiology

Section 1. Abstract: The objectives of this report were to describe the importance of food safety and food safety in the home, define foodborne illnesses, explain how food becomes compromised by microbes and to discuss common methods used to preserve food safety. Regarding the experiment, the objective was to compare the microbial count and diversity that develops from unwashed versus washed lettuce and open versus fresh milk. By analyzing and interpreting the results, connections between these findings and the best practices for maintaining food safety within your own home can be concluded. The results showed that the opened milk and the unwashed lettuce contained the highest number and diversity of microbes. Section 2. Introduction and Background: According to data from the Centers for Disease Control and Prevention (CDC), approximately one out of every six Americans falls ill due to foodborne pathogens, resulting in around 3,000 deaths annually 1 . Foodborne illnesses are caused by the consumption of contaminated food containing harmful microorganisms. Such illnesses pose a considerable public health risk, emphasizing the importance of preventing their transmission. Achieving this goal requires a collective effort, with a strong focus on food processing and preparation practices at all levels, including individual households. 1 https://www.cdc.gov/foodborneburden/estimates-overview.html

Food safety is important as it directly affects our health and well-being. Consuming contaminated food can result in foodborne illnesses, ranging from mild discomfort to severe and even life-threatening conditions. Microbes, such as bacteria, viruses, parasites, and fungi, can compromise food safety in various ways. They can contaminate food during production, processing, or even in our own homes if proper handling and storage practices are not followed. Factors like inadequate cooking temperatures, cross-contamination between raw and cooked foods, poor hygiene, and improper food storage conditions can all contribute to microbial contamination. 2 This laboratory experiment aims to focus on the spread of microorganisms and food safety. Through examining the microbial count and diversity that develops from unwashed vs washed lettuce and open vs fresh milk, we can make conclusions about food storage and safety practices. To begin this experiment the property safety precautions were taken: washing hands, gloves, face mask, gloves,apron, and goggles. In addition, the work surface was disinfected by wiping it with a 10% bleach solution. In the experiment, two separate petri dishes were created by boiling the agar, dried and then labeled. One plate was divided into two and labeled “ fresh milk ” and the other “ opened milk. ” The other plate was also divided into two and labeled “ washed lettuce ” and “ unwashed lettuce. ” A separate sterile swab from the packet was moistened with distilled water and rubbed on the unwashed lettuce and washed with soap 2 https://www.fsis.usda.gov/news-events/events-meetings/food-safety-education-month-preventing-cross-con tamination#:~:text=Cross%2Dcontamination%20is%20the%20transfer,they%20are%20not%20handled%20pro perly .

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and thoroughly dried lettuce. Then each swab was transferred onto its correctly labeled agar plate and completely coated with inoculant. A separate sterile swab from the packet was saturated with the milk that had been opened for 7 days and the fresh milk respectively. Then each swab was transferred onto its correctly labeled agar plate and completely coated with inoculant. The inoculated plates were placed bottom-side up (inverted) in the incubation location for 48 hours. All the used swabs were placed in a container of undiluted bleach and then thrown in the garbage. The work area was wiped down with a 10% bleach solution and items were washed and returned to the kit for further use. To clean up after the experiment, reusable equipment was soaked in a 10% bleach solution for 2 hours,then rinsed with tap water and allowed to dry before returning to the lab kit. Disposable equipment was soaked in a pure bleach solution for 2 hours before wrapping with paper towels, sealing in a plastic bag, and placing it in the garbage. The cultures were disposed of by soaking the containers and media in a pure bleach solution for 2 hours before taping closed, wrapping in paper towels, sealing in a plastic bag, and placing in the garbage. Lastly, the work area was wiped down with a 10% bleach solution and hands were washed. While there were no questions about forming a hypothesis in this lab, I assumed that the opened milk and unwashed lettuce would contain the highest number and diversity of microbes. Since the milk was opened for longer, it would allow for more microbes to form

and since the unwashed lettuce was not washed, it would have more microbes and germs on its surface. Section 3. Materials and Methods: The materials and/ or equipment used to conduct the experiment consisted of the student supplied materials and the science interacted kit supplied materials. The student supplied materials consisted of, one bottle of bleach, one bottle of distilled water, a digital camera or smartphone, a coffee cup, hand soap, isopropyl alcohol (rubbing alcohol), a large cooking pot with a minimum depth of 8 inches, fresh unwashed leaf lettuce, an oven mitt, a roll of paper towels, two small containers of milk, a source of tap water, and a stove or hotplate. The science interacted kit supplied materials consisted of an apron, a face mask with ear loops, two pairs of gloves, a pair of safety goggles, a permanent marker, two petri dishes that are 60 mm, two sterile swab packs ( two per pack) one test tube rack measuring 6 x 21 mm, one test tube clamp, 1 tryptic soy agar (TSA) 18 mL tube. Part one involves the preparation and inoculation of agar plates. Approximately 1 hour before starting the exercise, two agar plates are poured. A work area is cleared and all necessary materials are gathered. Safety precautions, such as wearing gloves, a face mask, apron, and goggles, are taken. The work surface is disinfected with a 10% bleach solution. The bottom of each agar plate is divided into two sections and labeled accordingly "washed

lettuce ” and “ unwashed lettuce ” and “ fresh milk ” and “ opened milk. ” A sterile swab is moistened with distilled water and rubbed on the surface of unwashed lettuce, transferring the sample to the "lettuce unwashed" section of one agar plate. The process is repeated with washed lettuce. Another sterile swab is saturated with opened milk and transferred to the "milk opened" section of the agar plate. The same is done with fresh milk. The inoculated plates are placed upside down in an incubation location for 48 hours. Afterward, the work area is cleaned, and items are washed and returned to the kit. Part two involves the observation and recording of microbial growth on the culture plates. After 48 hours, the plates are observed without removing the lids. The number of different colony types and the total number of colonies in each section are counted and recorded. A photo of the developed plates is taken and uploaded. The cleanup process includes soaking reusable equipment in a 10% bleach solution, rinsing them with tap water, and allowing them to dry. Disposable equipment is soaked in pure bleach solution, wrapped, sealed, and disposed of properly. The work area is cleaned, and hands are washed thoroughly. There were no specific laboratory techniques and equipment used to collect and analyze the data upon which the conclusions are based, rather each plate was examined with the eyes and the colonies were counted. There were no calculations or formulas needed to obtain the final results.

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Section 4. Results: After 48 hours, the two plates were observed and their findings were noted. The types of microbes and the number of total colonies were noted for each section. The “ fresh milk ” section contained no microbes or colonies present on the agar plate. The “ milk opened ” section contained one large colony that was round (with smaller colonies in it). It was circular and flat. There were also colonies growing around the perimeter, on the sides of this section. They were all attached, shiny looking and flat. The total number of colonies in this section was one colony plus the sides. The “ lettuce washed ” section consisted of very small circular, flat colonies. Each of the colonies was isolated and not touching others. The total number of colonies in this section was 40. The “ lettuce unwashed ” section consisted of large colonies, all touching each other, that were flat and convex shaped. The total number of colonies in this section was over 100. The general trend of the experiment showed that the cleaner or fresher the product was, the fewer

microbes it contained. The fresher milk and the washed lettuce contained less microbes than the opened milk and the unwashed lettuce. The bar graph shows that the cleaner and fresher products contained around half the number of microbes when compared to the less fresh products. Section 5. Discussion: As it is known, food safety is extremely important in preventing foodborne illnesses, since it can have severe health consequences. By ensuring that food is handled, stored, and prepared properly, the risk of contamination and the spread of harmful bacteria, viruses, or parasites is minimized. Based on this knowledge, if food is not stored and prepared properly, the risk of contamination and harmful microorganisms increases. It would be assumed that the fresh milk that had not been opened since it had been pasteurized would contain less microbes when compared to the opened milk that had been sitting in the refrigerator for a week. Additionally, it would be assumed that the unwashed lettuce that may have contained dirt, germs and bacteria would harbor more microorganisms than the washed lettuce, as the washed lettuce was washed with soap removing the bacteria before it was swabbed. Lettuce is an example of fresh food that is typically not grown in sterile conditions. This means that produce is exposed to microbes present in the soil and irrigation water. If the exposed produce is not properly cleaned before consumption, it can lead to foodborne illness

in humans. This is why it is necessary to wash produce before consumption and why we assumed that the unwashed lettuce would contain more microbes. 3 Liquids like milk undergo pasteurization, a method that involves heating milk to a specific temperature for a designated duration to eliminate harmful bacteria. This process effectively reduces microbial populations that are responsible for causing diseases. This practice aims to maintain aseptic conditions and minimize the presence of harmful microorganisms in food products. 4 The longer milk is opened for, the greater the presence of microbes will be. This is why the opened milk was expected to have more microbial growth than the fresh milk. Based on the experiment's findings, it was observed that there was a correlation between the cleanliness or freshness of a product and the presence of microbes. Specifically, the fresher milk and washed lettuce exhibited a lower microbial count compared to the opened milk and unwashed lettuce. It was noted that the cleaner and fresher products contained approximately half the number of microbes compared to the less fresh products. This was expected as it is known that when food is properly washed and safety protocols are taken into account, the less microbial growth will be present. 4 https://www.fda.gov/food/buy-store-serve-safe-food/raw-milk-questions-answers#:~:text=Pasteurization%20 is%20a%20process%20that,a%20set%20period%20of%20time . 3 https://www.sciencedirect.com/science/article/pii/S2405844023064812

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The data does support the original hypothesis as the hypothesis had stated that the opened milk and unwashed lettuce would contain the highest number and diversity of microbes, which was seen in the results of the experiment. The theory behind this experiment was to compare the amount of microbial growth on food items that practiced food safety and food items that did not practice food safety. The results of the experiments showed that when food safety was practiced, the number of microbes decreased, which was the goal of this experiment. The experimental results sustained the theory that when implementing food safety practices, a reduction in the number of microbes was present. This could be seen since the fresher milk and the washed lettuce contained less microbes than the opened milk and the unwashed lettuce. There were no noted errors that occurred and no noted errors due to the equipment used. Potential sources of error and recommendations to improve the procedure and results include making sure that the sterile swab was fully saturated in the dilated water before rubbing it on the lettuce and fully saturated in the milks. The results and the outcome of this experiment can be compared to the real world. It can be seen how important food is. Food safety is crucial for several reasons. Firstly, it helps prevent foodborne illnesses, which can have severe health consequences. By ensuring that food is handled, stored, and prepared properly, the risk of contamination and the spread of harmful bacteria, viruses, or parasites is minimized. Secondly, food safety promotes public health and well-being. When people have confidence in the safety of the food they consume, it contributes to overall health and reduces the burden on healthcare systems. Overall,

prioritizing food safety is vital to protect public health, maintain consumer trust, and facilitate safe and sustainable food systems. Ways to ensure food safety include temperature control, good hygiene practices, and cross contamination prevention. Proper temperature control is crucial in preventing microbial growth. Keeping perishable foods refrigerated at or below 40°F slows down bacterial growth and cooking food to appropriate temperatures (above 140 F) kills harmful microorganisms. 5 Good personal hygiene, such as regular handwashing, is essential in preventing the spread of bacteria. Proper sanitation of food preparation surfaces, utensils, and equipment also helps minimize microbial contamination. 6 Cross-contamination occurs when harmful microorganisms from one food item are transferred to another. To prevent this, it is important to separate raw and cooked foods, use separate cutting boards and utensils, and avoid using the same surfaces for different food items without proper cleaning. 7 By following these practices and implementing stringent food safety measures, the risk of microbial growth and foodborne illnesses can be significantly reduced, safeguarding public health and well-being. Section 6. Conclusion: 7 https://www.fsis.usda.gov/news-events/events-meetings/food-safety-education-month-preventing-cross-con tamination 6 https://www.cdc.gov/handwashing/handwashing-kitchen.html 5 https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/danger-zone- 40f-140f

The main goals of this report were to emphasize the significance of food safety, particularly in home settings, define foodborne illness, explore how microbes compromise food, and discuss common methods for preserving food safety. As for the experiment, its objective was to compare the microbial count and diversity between unwashed and washed lettuce, as well as opened and fresh milk. Through analysis and interpretation of the results, connections can be drawn between these findings and the recommended practices for ensuring food safety at home. The findings indicated that the highest number and diversity of microbes were present in the open milk and unwashed lettuce samples and that the opened milk and unwashed lettuce produced twice the amount of microbes as the fresh and washed lettuce. Ensuring food safety involves temperature control, good hygiene practices, and preventing cross-contamination. Proper temperature control, such as refrigeration and cooking at appropriate temperatures, inhibits microbial growth. Practicing good personal hygiene, sanitizing food preparation surfaces, and preventing cross-contamination further minimize the risk of foodborne illnesses. By implementing these measures, the risk of microbial contamination significantly decreases. Section 7. Citations: 1. 1. Estimates of foodborne illness in the United States. Centers for Disease Control and Prevention. November 5, 2018. Accessed November 29, 2023. https://www.cdc.gov/foodborneburden/index.html . 2. 1. Food Safety and Inspection Service. Food Safety Education Month: Preventing Cross-Contamination | Food Safety and Inspection Service. Accessed November 29, 2023.

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https://www.fsis.usda.gov/news-events/events-meetings/food-safety-education-mo nth-preventing-cross-contamination#:~:text=Cross%2Dcontamination%20is%20the %20transfer,they%20are%20not%20handled%20properly . 3. Mahami T, Odai BT, N.A. Nettey S, et al. Microbial food safety of lettuce produced under irrigated wastewater from Onyasia River in Ghana. Heliyon. August 22, 2023. Accessed November 29, 2023. https://www.sciencedirect.com/science/article/pii/S2405844023064812 . 4. Center for Food Safety and Applied Nutrition. Unpasteurized milk can pose a serious health risk. U.S. Food and Drug Administration. Accessed November 29, 2023. https://www.fda.gov/food/buy-store-serve-safe-food/dangers-raw-milk-unpasteuri zed-milk-can-pose-serious-health-risk . 5. Food Safety and Inspection Service. Safe Food Handling and Preparation | Food Safety and Inspection Service. Accessed November 29, 2023. https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation . 6. Handwashing: A healthy habit in the kitchen. Centers for Disease Control and Prevention. July 18, 2022. Accessed November 29, 2023. https://www.cdc.gov/handwashing/handwashing-kitchen.html .

Food Safety Micro Bio Lab report (1) (1)

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