Tolerance limits for the nutritional value of food products are very important for labelling purposes. This is because food products may not always contain exactly the same level of nutrients as calculated for the purpose of reporting on the label. Many factors can be responsible for the differences, which can be most reasonably divided into two groups:
1. natural,
2. resulting from production and storage.

However, the nutrient content of the tested product off the shelf should not differ significantly from the values ​​stated on the label, because such differences could mislead the consumer, and this is punishable. However, in order to avoid inaccuracies and arbitrariness in the interpretation of whether the difference in results is insignificant or exposes the customer to misleading, tolerance limits for nutritional labelling have been developed. This is discussed in the document "Guidelines for competent authorities on the verification of compliance with EU legislation in relation to: Regulation (EU) No 1169/2011 of the European Parliament and of the Council." This document was created to facilitate the control of food producers, as a result of a mutual agreement between the Commission services and the representatives of the Member States.

What does a tolerance limit actually mean?
It is worth recalling here that tolerance limits should not be confused with the rules for rounding the nutritional value, as discussed in the article entitled: Rules for rounding the nutritional value of labelled products.

A tolerance limit means acceptable differences between the value for a nutrient given on the label and the value found during official controls. Differences within the tolerance limits do not result in sanctions, otherwise the manufacturer must take steps to rectify this state of affairs, and what additional burdens will be associated with this is up to the control body to decide.

Directive 90/496/EEC and Regulation (EU) No 1169/2011 indicate that the energy and nutritional value should be given in the labelling as "average values". This means the value that best represents the quantity of the nutrient in a given food and that takes into account the natural characteristics of the raw materials used in the production of the food, seasonal variations, the effects of storage and seasoning, and other factors that may cause variations in the actual value. The values ​​given should, as appropriate, be average values ​​based on:

the manufacturer's analysis of the food;

calculations from known or actual average values ​​of the ingredients used;
calculations from generally available and accepted data. The actual amount of a nutrient in a product may differ from the value stated on the label due to factors such as:

the source of the data regarding the value, data may be obtained from literature e.g. calorie tables, or copied from the raw material specification of the supplier and calculated by substitution into a formula or using a program such as the Foodcal Nutrition Calculator instead of performing expensive laboratory analysis,
the accuracy of the laboratory analysis, it is common knowledge that the results of analyses from different laboratories may differ slightly, this is influenced by similar conditions, i.e. storage conditions, transport conditions, quality of laboratory equipment, measurement error,
variation in raw materials,
processing effects,
nutrient stability
storage conditions and period.

Regardless of the method used to obtain the nutritional information, food business operators should act in good faith to ensure a high degree of accuracy of such nutritional information. In particular, the values ​​stated should be close to the average values ​​for many batches of food and should not be set at the minimum or maximum of a defined tolerance range.

Table – Tolerance limits for foods other than food supplements including measurement uncertainty.

Source: KOMISJA EUROPEJSKA, DYREKCJA GENERALNA DS. ZDROWIA I KONSUMENTÓW (grudzień 2012).WYTYCZNE DLA WŁAŚCIWYCH ORGANÓW W SPRAWIE KONTROLI ZGODNOŚCI Z PRAWODAWSTWEM UE W ODNIESIENIU DO: rozporządzenia  Parlamentu  Europejskiego  i  Rady  (UE)  nr  1169/2011  z dnia  25 października 2011 r. w sprawie przekazywania konsumentom informacji   na   temat   żywności,   zmiany   rozporządzenia   (WE)   nr 1924/2006 Parlamentu Europejskiego i Rady i rozporządzenia (WE) nr 1925/2006 Parlamentu Europejskiego i Rady oraz uchylenia dyrektywy Komisji    87/250/EWG,    dyrektywy    Rady    90/496/EWG,    dyrektywy    Komisji       1999/10/WE,       dyrektywy       2000/13/WE       Parlamentu Europejskiego i Rady, dyrektyw Komisji 2002/67/WE i 2008/5/WE oraz rozporządzenia Komisji (WE) nr 608/2004 oraz dyrektywy  Rady  90/496/EWG  z  dnia  24  września  1990  r.  w  sprawie  oznaczania wartości odżywczej środków spożywczych oraz dyrektywy   2002/46/WE   Parlamentu   Europejskiego   i   Rady   z   dnia   10    czerwca    2002    r.    w    sprawie    zbliżenia    ustawodawstw    państw członkowskich odnoszących się do suplementów żywnościowych w zakresie określenia limitów tolerancji dla składników odżywczych wymienionych na etykiecie.