Experts have developed guidance to help food firms decide what other information to give consumers besides use-by or best-before dates to ensure food safety.

The European Food Safety Authority (EFSA) scientific opinion covers storage conditions, time limits for consumption after food has been opened and thawing of frozen items.

Setting a limit for consumption in days after opening a package, also known as secondary shelf-life, is complex but experts have created a decision tree with five questions. Consumer behavior and reasonably foreseeable conditions of use also need to be considered, they said.

After opening the package, contamination may occur via air flow, fluid drip or due to consumer handling via hands, utensils or containers, introducing new pathogens into the food and factors such as temperature and gas atmosphere may change, affecting microbiological safety.

Factors to consider
For those products where opening the packaging leads to a change in the type of pathogenic microorganisms in the food or factors increasing their growth compared to the unopened product, the tool shows the secondary shelf life should be shorter or the same as the initial use-by or best-before date.

A shorter time limit for consumption after opening the package than the original date means that the secondary shelf-life in days should be shorter than the number of days between the time of opening the package and these dates. The guidance does not clarify how the time limit for consumption can be worked out to be shorter than the initial date.

Foods covered are non-frozen, raw and processed, prepacked foods. After opening, the food may be stored in another container or used as an ingredient in a multi-component meal and time limits after opening refer to before consumption or further processing of the food.

When the package of a food supporting growth is opened close to the end of the shelf-life date, higher concentrations of bacteria can be expected than when it is opened earlier. The point in time a food package is opened may influence the initial concentration of pathogens at the time of opening, concentration of spoilage organisms and the growth potential of pathogens that are initially present or introduced after opening.

EFSA experts previously developed a decision tree of 10 questions for food company officials to help them decide whether a “use by” or “best before” date should be used. 

Defrosting advice
Freezing prevents growth of some pathogens, however, some survive frozen storage, recover during thawing and then grow and produce toxins in food, if conditions are favorable. During handling of thawed foods, additional contamination may occur from the hands, contact surfaces like utensils, or from other foods.

Thawing should occur at low temperatures, such as in the refrigerator; thawed foods should be kept in the original packaging or a clean container to avoid contamination; consumers should follow the manufacturer’s instructions on storage and preparation to ensure food stays safe; and defrosted food should not be refrozen after thawing.

Recommendations included to collect time-temperature data on reasonably foreseeable storage conditions of foods in EU countries; address knowledge gaps on the effects of thawing on bacteria and to generate evidence-based advice on time and temperature storage conditions and food preparation after thawing for items other than frozen vegetables.

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