Is it safe to eat queso when pregnant? (main risks)

In this article, we will discuss whether it is safe to eat queso when pregnant, what are the risks of eating queso when pregnant, and how to reduce the risk of eating queso when pregnant.

Queso is the short name given to queso fresco, is a fresh non-melting Mexican cheese of a mild taste and crumbly texture. It is also produced and commercialised in the United States.

Is it safe to eat queso when pregnant?

No, it is not safe to eat queso when pregnant, unless it is previously cooked. The consumption of uncooked queso fresco has been reported to cause food outbreaks, including outbreaks caused by Listeria monocytogenes, (1, 3, 4).

Listeria monocytogenes is a pathogenic bacteria of great concern during pregnancy and can be found in queso fresco (1, 3, 5), although all fresh cheese commercialised in the United States is made with pasteurised milk (1).

Why eating queso is not safe when pregnant?

Queso is not safe during pregnancy because it can carry the pathogenic bacteria Listeria monocytogenes, which can cause the disease listeriosis. In pregnant women, listeriosis can lead to severe consequences, including miscarriage (1, 3, 6).

Even when produced with pasteurised milk, which is the case for all dairy products commercialised in the United States, analysis of queso fresco samples has raised concern regarding post-packing contamination in the production facilities (5).

What are the risks of eating queso when pregnant?

The risks of eating queso when pregnant are related to foodborne illnesses. Queso fresco, like other fresh cheeses, is characterised by a high moisture and high pH, which favours microbial growth (1).

The risks of eating queso fresco when pregnant are summarised in the table below:

Risk Description Consequence

Listeriosis

Listeriosis is a foodborne infection caused by the bacteria Listeria monocytogenes. It is generally destroyed by the pasteurisation of milk. When queso is made from unpasteurised milk, the risks are very high. When the queso is made from pasteurised milk, contamination often occurs after the thermal treatment by handling and during the packing of the product (2, 5). Listeriosis causes nausea, diarrhoea, fever, muscle pain and flu-like symptoms. When pregnant, infection caused by Listeria can lead to premature birth, stillbirth and miscarriage. Other individuals with a weakened immune system can also be severely affected (3, 6).

Other foodborne illnesses

Foodborne infections can occur due to the ingestion of contaminated queso, even when produced with pasteurised milk. According to studies, post-pack contamination is a concern in many queso production facilities. Pathogens such as Escherichia coli, coliforms, moulds and yeasts have been found in commercial queso products (5). The risks of consuming queso made with unpasteurised milk increase and can lead to infections by Staphylococcus, Salmonella and Shiga toxin-producing Escherichia coli (4). Pregnant women are in general more susceptible and more severely affected by foodborne infections and foodborne poisoning. In this way, the ingestion of contaminated queso can more easily lead to a foodborne infection, leading to damage of the intestinal tract and symptoms such as diarrhoea, vomiting and dehydration. Poisoning by Shiga toxin can lead to bloody diarrhoea and kidney failure (3, 6). 

How to reduce the risks of eating queso when pregnant?

To reduce the risk of eating queso when pregnant, you should:

  • Choose a queso that has been produced with pasteurised milk: look for a label addressing the origin of the cheese and if the milk has been pasteurised (2, 3, 4, 5).
  • Buy queso and consume it within its expiration date.
  • Reject the queso when any signs of spoilage are present, such as an unpleasant odour or flavour, changes in the texture or colour, growth of mould, or formation of slime or gas (7).
  • Avoid eating queso fresco when going to a Mexican restaurant, as the origin of the cheese is unknown.
  • Follow good hygienic practices by washing your hands before handling food and keeping the cooking utensils and cooking place clean. Avoid handling cooked and uncooked foods at the same time (3).
  • Store the queso in the refrigerator at all times and check the refrigerator temperature to ensure it is low enough at 4 °C (40 °F) or below (1).
  • Cook the cheese before eating or heat it to a temperature of 165 °F (74 °C) (3).

What are the alternatives to queso when pregnant?

The alternatives to queso when pregnant are summarised in the table below. Their characteristics and benefits are compared to the queso:

Cheese Characteristics Benefits

High moisture mozzarella

Mozzarella is made with pasteurised milk and does not undergo ageing. It has a soft texture and relatively high moisture content, mild and milky flavour, a good melting quality and stretchability, and can be used as toppings and eaten uncooked or cooked. Mozzarella has a relatively low sodium content and contains a higher amount of proteins than queso (7). My experience says that frying mozzarella for some time will make it similar to fried queso.

Cream cheese

Cream cheese is made with pasteurised milk. It can be made by acid or rennet-induced coagulation of the curd. It has an acidic flavour and a semi-soft and creamy texture. My suggestion is to include cream cheese in cold dishes, such as salads. Cream cheese is relatively low in protein, however, it is a source of milk fat, which is related to health benefits, especially due to the presence of phospholipids and milk fat globule membrane (8). 

Conclusion

In this article, we discussed whether it is safe to eat queso when pregnant, the risks of eating queso when pregnant, how to reduce the risks of eating queso and what are the alternatives to queso when pregnant.

Queso is often served in Mexican restaurants and has the unique property of not being melted when cooked. Although some people prefer to eat cheese made with unpasteurised milk due to their flavour, I don´t recommend it. 

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References

1.-

Tomasula PM, Renye JA, Van Hekken DL, Tunick MH, Kwoczak R, Toht M, Leggett LN, Luchansky JB, Porto-Fett AC, Phillips JG. Effect of high-pressure processing on reduction of Listeria monocytogenes in packaged Queso Fresco. Journal of dairy science. 2014 Mar 1;97(3):1281-95.

2.-

Tunick MH, Van Hekken DL, Guo L, Tomasula PM. Chemistry of queso fresco. InHispanic foods: Chemistry and bioactive compounds 2012 (pp. 11-23). American Chemical Society.

3.-

Dean J, Kendall P. Food safety during pregnancy. Food and nutrition series. Food safety; no. 9.372. 2004.

4.-

Dash KK, Fayaz U, Dar AH, Shams R, Manzoor S, Sundarsingh A, Deka P, Khan SA. A comprehensive review on heat treatments and related impact on the quality and microbial safety of milk and milk-based products. Food Chemistry Advances. 2022 Oct 1;1:100041.

5.-

Holle MJ, Ibarra-Sánchez LA, Liu X, Stasiewicz MJ, Miller MJ. Microbial analysis of commercially available US Queso Fresco. Journal of dairy science. 2018 Sep 1;101(9):7736-45.

6.-

Switaj TL, Winter KJ, Christensen SR. Diagnosis and management of foodborne illness. American family physician. 2015 Sep 1;92(5):358-65.

7.-

Clark S, Costello M, Drake M, Bodyfelt F, editors. The sensory evaluation of dairy products. Springer Science & Business Media; 2009 Jul 30.

8.-

Guinee TP, Hickey M. Cream cheese and related products. Dairy fats and related products. 2009 May 15:195-256.