Food allergies are very common in both children and adults, and some fear that wine can be a potential allergenic threat to certain individuals. From the alcohol in the wine to the chemicals and reagents used in the winemaking process, determining levels of potential allergens in wine for labeling and warning purposes has become the main concern spearheading several legislative measures in Europe and elsewhere all over the globe.
Milk allergies, which are different from milk intolerances, occur throughout the globe though are more common in children than in adults. This allergy, in fact, is quite rare, affecting only 0.062% of Italian adults. In white winemaking, potassium caseinate is often used as a fining agent and is derived from milk. Potassium caseinate works as a fining agent by binding to compounds that cause cloudiness in wine and allow those compounds to be removed and the final wine clarified. During this process, there is a chance that not all of the fining agent is removed, thereby causing a potential health risk to those that suffer from milk allergies.
Alternatives to potassium caseinate (or any casein-based compounds) are available to use during the winemaking process to help avoid possible negative health risks due to milk allergy in certain individuals, however, do wines even possess high enough levels of the compound to elicit an allergic response? The paper presented today aimed to examine the levels of caseinate in many commercial wines, to determine if residual levels are high enough to potentially cause allergic reactions in adults and if adding a warning label to a wine bottle is a necessary precaution.
Both experimental and commercial wines were examined in this study. Experimental wines were put into treatment groups as follows: untreated controls; samples fined with 20g/h L of commercical caseinate; samples fined with 50g/h L; and samples with both of these caseinate dosages with 0, 30, 60, or 90g/h L of bentonite added.
2 liters of wine were first combined with caseinate (at 0, 20, or 50g/h L) then kept at room temperature for 24 hours. After this time, bentonite was added (at 0, 30, 60, or 90g/h L) and then kept at room temperature for another 24 hours. All experimental wines were passed through membranes with a pore size of 3μm. In total, there were 16 experimental wines and 14 controls (not treated with casein).
Commercial wines were sent to the researchers from all over Italy with the requirement that all wines had be fined with casein. A total of 59 white wines, 2 rosé wines, and 2 red wines were sent in from around Italy. All commercial wines were filtered through membranes of pore sizes less than or equal to 1um. Commercial caseinate used in wines were: alpha caseinate, caseinato di potassio, Caseo Cell, Clarasi DC, Clarito Spray Dry, Clarito SP, Kaseomax, Micron 96, Micron XL, potassium caseinate S, Protoclar, and Vinpur Special.
The following characteristics of the wines were measured: alcohol by volume, total alcoholic strength, sugar content, total acidity, volatile acidity, pH, ash, total dry extract, reduced extract, and total phenolic content.
Casein was measured using several methods, including SDS-page/western blotting and ELISA. Tests were performed in triplicate.
The entire experiment included 16 experimental wines and 63 commercial wines, all fined with caseinates, with or without bentonite, and microfiltered. Untreated wines were used as controls.
- SDS-page/western blotting proved to be an ineffective method for measuring casein in wine, as the binding capabilities of the proteins used in that analysis were nonspecific and bound to many more compounds than casein itself, thereby making it impossible to distinguish what compounds were casein, and what compounds were not.
- Results indicated that the antibodies used in the ELISA analysis were very specific to caseins and β-caseins, which indicates that detection of casein in commercial wines is guaranteed (according to the authors) using this method.
- Control wines (no casein added) were found to be completely free of casein by ELISA analysis.
- All (experimental and commercial) wines were found to be free from detectable levels of allergenic casein residues (less than 0.28ppm).
o This result was the same of all wines, regardless of the varietal, dosage of fining agent, and winemaking practices.
According to the results of this study, there was no detectable casein residues remaining (less than 0.28ppm) in all wines studied. This suggests that those individuals with milk allergies should not be concerned about if a wine is treated with casein during the winemaking process. According to the authors, clinical trials should not need to be performed, since casein was not present in detectable levels that would have any effect on those very few adults with milk allergies.
The authors put forth a “worst case scenario” situation in order to stress how little casein is actually present in Italian commercial wines which I will describe here. Clinical evidence has shown that the 0.6mg of milk protein (casein) can cause major problems in some children with milk allergies (children are more sensitive than adults, in general, to milk protein). If an adult were sensitive to that level of casein/milk protein, they would have to consume 1.2 liters of wine in a short period of time in order to elicit an allergic reaction. Since the adult threshold for casein/milk protein sensitivity is more along the levels of 10mg (instead of 0.6mg), it is near impossible for commercial wines to elicit allergic reaction in those individuals affected by a milk protein allergy.
I’d be curious to see an analysis of casein levels from all over the world; however, I’m fairly certain that we’d see the same results that we are seeing in this study. Individuals with a true allergy to milk (NOT a lactose intolerance, which is a different medical problem) should not be concerned if a wine was treated with casein during the winemaking process, nor there a need to require labeling a wine as having undergone casein treatment.
I’d love to hear what you all think about this topic! Please feel free to leave your comments!
Source: Restani, P., Uberti, F., Danzi, R., Ballabio, C., Pavanello, F., and Tarantino, C. 2012. Absence of allergenic residues in experimental and commercial wines fined with caseinates. Food Chemistry 134: 1438-1445.
I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!