How to know if the lettuce is spoiled? (5 easy methods)

In this brief article, we are going to answer the question “How to know if the lettuce is spoiled”, discuss the different methods of identifying the spoiled lettuce and the potential side effects of eating spoiled lettuce.

How to know if the lettuce is spoiled? 

If you are not sure if your lettuce is spoiled or not, you can look at the following five common signs that that will indicate spoilage:

Important: be aware that if you eat spoiled lettuce, you are more likely to acquire a foodborne disease that could lead to serious health problems (1-6).

It is therefore not recommended to eat spoiled lettuce!

1. Discoloration: fresh lettuce should have vibrant, green leaves, except for Red Coral, which seems to have purple leaves. When discolorations occur, they are easy to spot. Discolored or slimy spots are a clear indication that the lettuce has gone bad. 

If you notice any darkening, browning, or yellowing of the leaves, it may also indicate spoilage. If you notice brown spots in a few leaves and the others remain healthy, you may cut the bad ones aside and carefully eat the healthy ones.

2. Foul odor: fresh lettuce should have a mild, fresh aroma, while spoiled lettuce often emits a strong, unpleasant smell. It will be simple to notice the rotting scent since it will be quite terrible. 

If you detect any off-putting smell, like a sour or rotten scent, this is a clear indication that your lettuce has spoiled. You should immediately throw your lettuce out!

3. Wilted or shriveled appearance: when your lettuce is past its prime, it tends to wilt and lose its crispness. The leaves may become limp, and the overall appearance may appear droopy or shriveled. 

If the lettuce looks sad and lifeless, this is a clear indication of spoilage. Such changes can be detected by just looking at the leaves or caressing them.

4. Slimy texture: fresh lettuce leaves should be crisp and firm. When lettuce starts to spoil, the texture changes, and the leaves become slimy or mushy to the touch. If your lettuce feels slippery or has a slimy film, it is always best to discard it.

5. Mold growth: the presence of molds is a sure sign of spoilage. Inspect the lettuce carefully, especially around the stem and any crevices, for any fuzzy or powdery mold patches. 

If you spot molds on the lettuce, it is no longer safe to consume. Be careful! Remember that eating molds and their mycotoxins can lead to severe health problems (3-7).

Remember that if you are not sure about the freshness of your lettuce, it is always better to err on the side of caution and discard it to avoid any potential health risks.

Can you get sick from eating spoiled lettuce? 

Yes, eating spoiled lettuce can pose several risks to your health due to the presence of harmful microorganisms such as Salmonella, certain strains of E. coli and Listeria monocytogenes and their toxins (4-6, 8).

Some of the potential dangers and symptoms that you could experience after consuming spoiled lettuce are:

• Foodborne bacterial infections: consuming lettuce contaminated with harmful bacteria like Salmonella, E. coli O157:H7 and Listeria monocytogenes can lead to symptoms such as diarrhea, abdominal cramps, fever, vomiting, nausea, headache, stiff neck, confusion, and in severe cases, it could even be fatal (6)

• Foodborne parasitic infections: consuming lettuce contaminated with harmful parasites such as Cyclospora cayetanensis can lead to symptoms like diarrhea, abdominal pain, loss of appetite, weight loss, fatigue, and flu-like symptoms (2).

• Foodborne viral infections: consuming lettuce contaminated with viruses like norovirus can lead to norovirus gastroenteritis, which includes vomiting, diarrhea, nausea, stomach cramps, and in some cases, low-grade fever and headache (1).

• Toxins and toxins-producing bacteria: consuming lettuce contaminated with toxins-producing bacteria like Staphylococcus aureus and Clostridium botulinum can result in staphylococcal food poisoning and botulism, respectively (3-4). 

Symptoms may include rapid onset of nausea, vomiting, stomach cramps, and diarrhea, blurred vision, difficulty swallowing, muscle weakness, paralysis, and in severe cases death (3).

If you experience any of these symptoms after consuming lettuce, you should seek medical attention immediately.

What should you do if you suspect you have eaten spoiled lettuce? 

If you have eaten spoiled lettuce, and you are experiencing any of the above-mentioned symptoms, here we bring you some advice on how to react:

• Monitor your symptoms: pay close attention to any changes in your body and monitor for symptoms of foodborne illness. You should also note the onset and severity of symptoms.

• Stay hydrated: drink plenty of beverages containing electrolytes to prevent dehydration caused by vomiting or diarrhea (9).

• Seek medical advice: if you experience severe symptoms, prolonged illness, or if you are part of a high-risk group (such as young children, pregnant women, older adults, or individuals with weakened immune systems), it is very important to seek medical attention immediately. 

Contact your healthcare provider and inform them about your symptoms and the possibility of consuming spoiled lettuce.

• Report the incident: if you suspect that your lettuce was contaminated and poses a health risk, consider reporting the incident to your local health department or food safety authority. They can investigate and take appropriate measures to prevent further cases of foodborne illness.

Be aware that these are general recommendations, and it is always best  to ask your personal doctor for personalized advice.

How to properly handle lettuce to avoid spoilage? 

You can follow the next handling tips if you want to avoid spoilage and extend the shelf life of your lettuce:

• Selection and purchase: as mentioned before, we recommend you to always choose fresh-looking lettuce with vibrant, crisp leaves. 

You should avoid lettuce with any signs of wilting, discoloration, or damage. In the case of buying pre-packaged lettuce, you must always check the “best-by” date to ensure freshness.

• Storage: on one hand, if you want to store your lettuce for a few days (i.e., short-term storage), you should place unwashed lettuce in a perforated plastic bag or wrap it loosely in a paper towel. 

It is recommended that you store your lettuce in the vegetable crisper drawer of your refrigerator, which can help you to maintain its humidity and prevent drying out. 

On the other hand, if you want to store your lettuce for more than a few days (long-term storage), you should consider washing and thoroughly drying the lettuce leaves and placing them in an airtight container lined with a dry paper towel to absorb moisture. 

You can then store the container in the refrigerator’s crisper drawer for later use.

• Proper washing: You should wash your lettuce just before consumption rather than before storage to prevent excess moisture and premature spoilage. 

You could pat them dry with a clean kitchen towel or use a salad spinner to remove excess water.

• Avoid cross-contamination: It is very important that you keep your lettuce away from raw meats, poultry, or seafood to prevent the risk of bacterial contamination. 

For that, you should use separate cutting boards, knives, and utensils for different food items to prevent cross-contamination.

It is important that you know that different types of lettuce have different shelf lives (10-11). For example, the iceberg lettuce has a relatively longer shelf life compared to other types. 

If stored properly, iceberg lettuce can last up to 1-2 weeks in the refrigerator, while romaine lettuce typically stays fresh for about 1 week when stored correctly. 

The more perishable lettuce are the leaf lettuce varieties (e.g., green leaf, and red leaf) that can last only around 3-7 days when stored properly.

Remember that it is wise to use your judgment and inspect the lettuce for signs of spoilage before consuming. Your safety comes first!

We recommend you to buy and consume your fresh lettuce as soon as possible to safely enjoy its optimal freshness and flavor.

Taste:

Conclusion:

In this brief article, we answered the question “How to know if the lettuce is spoiled”, and discussed the different methods of identifying the spoiled lettuce and the potential side effects of eating spoiled lettuce.

References:

1. Müller L, Rasmussen LD, Jensen T, Schultz AC, Kjelsø C, Barnadas C, et al. Series of Norovirus Outbreaks Caused by Consumption of Green Coral Lettuce, Denmark, April 2016. PLoS Curr [Internet]. 2018 [cited 2023 May 16];8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5074700/  

2. Almeria S, Shipley A. Detection of Cyclospora cayetanensis on bagged pre-cut salad mixes within their shelf-life and after sell by date by the U.S. food and drug administration validated method. Food Microbiol. 2021 Sep 1;98:103802. https://www.sciencedirect.com/science/article/pii/S0740002021000678  

3. Petran RL, Sperber WH, Davis AB. Clostridium botulinum Toxin Formation in Romaine Lettuce and Shredded Cabbage: Effect of Storage and Packaging Conditions. J Food Prot [Internet]. 1995 [cited 2023 May 16];58(6):624–7. Available from: https://pubmed.ncbi.nlm.nih.gov/31137426/  

4. Standing TA, Du Plessis E, Duvenage S, Korsten L. Internalisation potential of Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica subsp. enterica serovar Typhimurium and Staphylococcus aureus in lettuce seedlings and mature plants. J Water Health [Internet]. 2013 Jun 1 [cited 2023 May 16];11(2):210–23. Available from: http://iwaponline.com/jwh/article-pdf/11/2/210/395477/210.pdf  

5. Kyere EO, Palmer J, Wargent JJ, Fletcher GC, Flint S. Colonisation of lettuce by Listeria Monocytogenes. Int J Food Sci Technol [Internet]. 2019 Jan 1 [cited 2023 May 16];54(1):14–24. Available from: https://onlinelibrary.wiley.com/doi/full/10.1111/ijfs.13905  

6. de Oliveira Elias S, Noronha TB, Tondo EC. Salmonella spp. and Escherichia coli O157:H7 prevalence and levels on lettuce: A systematic review and meta-analysis. Food Microbiol. 2019 Dec 1;84:103217. https://pubmed.ncbi.nlm.nih.gov/31421760/  

7. Pleadin J, Frece J, Markov K. Mycotoxins in food and feed. In: Advances in Food and Nutrition Research. Academic Press Inc.; 2019. p. 297–345. https://pubmed.ncbi.nlm.nih.gov/31351529/   

8. Kroupitski Y, Pinto R, Brandl MT, Belausov E, Sela S. Interactions of Salmonella enterica with lettuce leaves. J Appl Microbiol [Internet]. 2009 Jun 1 [cited 2023 May 16];106(6):1876–85. Available from: https://academic.oup.com/jambio/article/106/6/1876/6719207  

9. McRobert GR. THE TREATMENT OF BACTERIAL FOOD POISONING. Br Med J [Internet]. 1934 Aug 8 [cited 2023 May 10];2(3841):304. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2445530/  

10. Allende A, Aguayo E, Artés F. Microbial and sensory quality of commercial fresh processed red lettuce throughout the production chain and shelf life. Int J Food Microbiol. 2004 Mar 1;91(2):109–17. https://pubmed.ncbi.nlm.nih.gov/14996454/  

11. Peng H, Simko I. Extending lettuce shelf life through integrated technologies. Curr Opin Biotechnol [Internet]. 2023 Jun 1 [cited 2023 May 16];81:102951. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0958166923000617