Dietitian Sindi-marie de Beer helps us understand why it’s best to steer clear of salad bars while undergoing cancer treatment.
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This is a difficult question to answer since there is miniscule research. However, the best way is to break this question up in to food safety of salad bars and what happens to your immunity during cancer treatment.
Salad bars
Salad bars and ready-to-eat salads have become increasingly popular due to their numerous health benefits. These include being rich in antioxidants and essential micronutrients like vitamin C, folic acid, and carotenoids. Salads also contribute to reducing childhood obesity and provide a convenient option for those following vegan and vegetarian diets.1
While salads are generally considered healthy and recommended for most people, caution is necessary because they are often consumed raw with little or no heat treatment. This makes them susceptible to cross-contamination from other cooked foods.
Foodborne illness
Food safety is vital for everyone, but especially for those with compromised immune systems (when your immune system isn’t as strong as it should be due to illness treatments).
Common microorganisms responsible for foodborne illnesses include norovirus, campylobacter, salmonella, listeria monocytogenes, and Shiga toxin-producing Escherichia coli. Other pathogens that may occasionally cause illness are staphylococcus aureus, clostridium species, bacillus cereus, yersinia enterocolitica, and certain parasites.
Symptoms of infection can range from abdominal pain, diarrhoea, and vomiting to more severe outcomes like respiratory problems and even death.1 Key sources of outbreaks include poultry, ground meat, seafood, dairy, and fresh produce like those found at salad bars.3
Fresh produce is naturally exposed to complex microorganisms due to various factors, such as farm conditions, harvesting equipment, handling practices, processing, transportation, and distribution. Proper handling of fresh produce is crucial, as mistakes or shortcuts by restaurants or chefs can lead to contamination outbreaks.2
Salads containing tuna, cheese, mayonnaise, or chicken can introduce cross-contamination. The juices released from stored salad leaves create a high-moisture environment that promotes the growth and attachment of salmonella.
Certain salad dressings and seasonings can further increase moisture levels, encouraging microbial growth. However, the fat, salt, spices, and acidity in some salad dressings may inhibit this growth, offering a level of protection.3
Cancer treatment and your immunity
Cancer treatments, such as chemotherapy, targeted therapy, radiotherapy, and high doses of steroids are known to affect the immune system. Specifically, chemotherapy works by destroying rapidly growing cells, including cancer cells and normal body cells found in the blood, bone marrow, mouth, intestinal tract, nose, nails, vagina, and hair.
White blood cells, produced in the bone marrow, play a crucial role in preventing infections in the body. There are several types of white blood cells, each with distinct functions:
- Neutrophils are the most abundant type of white blood cells and are the first line of defence against infections, particularly bacterial infections. They respond quickly to sites of infection, engulfing and destroying pathogens through a process called phagocytosis.
- Lymphocytes are crucial for the immune response. They are further divided into two main types:
* B cells produce antibodies that specifically target and neutralise foreign invaders, such as bacteria and viruses.
* T cells play a direct role in killing infected cells and regulating the immune response. There are different types of T cells, including helper T cells which support other immune cells, and cytotoxic T cells which destroy infected or cancerous cells.
- Monocytes are larger cells that differentiate into macrophages and dendritic cells when they move into tissues. Macrophages are important for engulfing pathogens and dead cells, while dendritic cells help activate T cells by presenting antigens.
- Eosinophils and basophils play a role in the inflammatory response as well as regulating an allergy response.5
How chemotherapy affects the immune system
During chemotherapy, you may experience neutropenia, which means you have fewer than the desired amount of white blood cells (especially neutrophils—the first line of defence). Neutropenia increases your risk of infections and compromises your ability to fight them off. You can get infections and bacteria from air, water, soil, or food.4
After chemotherapy, it may take your body 21 to 28 days to recover and rebuild your immune system, allowing for the regeneration of these vital white blood cells.
Take away message
While salad bars can offer numerous health benefits, if you are undergoing cancer treatment, you should exercise caution due to your compromised immune system. The potential for foodborne illnesses is heightened when consuming raw produce, particularly in settings where cross-contamination may occur.
Understanding the types of microorganisms that can cause illness and recognising the importance of proper food handling are crucial steps for maintaining safety.
As cancer treatments like chemotherapy can lead to neutropenia and reduce the body’s ability to fight infections, it’s essential to be mindful of your food choices. Ultimately, prioritising food safety and being aware of the risks associated with raw foods can help you with enjoy nutritious meals while minimising their risk of infection.
Food safety tips
1. Wash hands regularly
Wash hands with soap and warm water for 20 seconds before handling food, after touching raw foods, and after using the bathroom.
2. Clean surfaces and utensils
Keep kitchen surfaces, utensils, and cutting boards clean. Use separate boards for raw meat and vegetables to avoid cross-contamination.
3. Cook food thoroughly
Ensure meats, poultry, fish, and eggs are cooked to the correct internal temperature using a food thermometer.
4. Store food properly
Refrigerate perishables within two hours. Keep the fridge below 5°C (40°F) and the freezer at -18°C (0°F).
5. Wash produce
Rinse fruits and vegetables under running water, even if you plan to peel them.
6. Use safe water
Ensure water is safe to consume.
7. Keep food at safe temperatures
Keep hot foods above 60°C (140°F) and cold foods below 5°C (40°F). Avoid leaving food out for more than two hours.
8. Thaw food safely
Defrost food in the fridge, or cold water, and cook it directly after thawing.
9. Check expiry dates
Regularly check and discard food past use-by or best-before dates. Always use fresh produce.
References
- Gourama, H. (2020) ‘Foodborne pathogens’, in Demirci, A., Feng, H. and Krishnamurthy, K. (eds) *Food Safety Engineering*. Food Engineering Series. Cham: Springer. Available at: https://doi.org/10.1007/978-3-030-42660-6_2 .
- Shahbaz, M., Bilal, M., Zubair, S., Akhlaq, M. and Moiz, A. (n.d.) ‘Microbiological safety of fresh-cut produce and salads served at quick service restaurants’, *[Biomedical Journal of Sientific & Technical Research [volume and issue number if available]. Available at: [DOI: 10.26717/BJSTR.2022.47.007536] (Accessed: [ 16 December 2022]).
- Osaili, T.M., Hasan, F., Al-Nabulsi, A.A., Olaimat, A.N., Ayyash, M., Obaid, R.S. and Holley, R. (2023) ‘A worldwide review of illness outbreaks involving mixed salads/dressings and factors influencing product safety and shelf life’, Food Microbiology, 112, p. 104238. Available at: https://doi.org/10.1016/j.fm.2023.104238
- Centers for Disease Control and Prevention (2024.) ‘Preventing infections in cancer patients’, *CDC*. Available at: https://www.cdc.gov/cancer-preventing-infections/patients/index.html.
5. Cancer Research UK (2023) ‘The immune system and cancer’, *Cancer Research UK*. Available at: https://www.cancerresearchuk.org/about-cancer/what-is-cancer/body-systems-and-cancer/the-immune-system-and-cancer
MEET THE EXPERT – Sindi-marie de Beer
Sindi-marie de Beer is a registered dietitian with a passion for imparting positive transformations through the realm of nutrition. She is committed to fostering well-being among those grappling with chronic or life-changing conditions, such as cancer, and the elderly.
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