Safety of Commercial Fruit Yogurts Beyond the Stated Expiration Date: Physicochemical, Textural, Microbiological, and Sensory Evaluation

Consumers believe that expired products are unsafe, and, in most cases, misinterpreting the information on food labels often leads to large amounts of food waste. Yogurt is among the most widely eaten dairy products that can still be consumed after its expiration date, even though most consumers throw it away the very day it expires. The aim of this study was to determine whether commercial yogurts currently available on the market remain safe for consumption after their expiration date, with a view to reducing the amount of food waste generated in households. Therefore, the quality, stability, and edible safety of 10 commercial yogurts (two plain with 2% and 4% fat and the others with fruit, such as apricots, strawberries, bananas, blueberries, berries and strawberries, blackberries and raspberries, and cherries) stored at 4°C before and at the expiration date were investigated. Physicochemical, textural, microbiological, and sensory analyses were performed to evaluate changes in functionality, safety, and acceptability of these yogurts. The results showed that, prior to their expiration date, certain yogurt samples (with apricots, strawberries, and blueberries, as well as plain yogurt with 4% fat) tested positive for total coliform bacteria, with values ranging from 20 to 50 CFU/g, suggesting substandard hygiene practices and insufficient sanitary conditions during and following the production process. No Escherichia coli, Listeria, Salmonella, Enterobacter spp., or Enterococcus spp. were detected in any of the yogurt samples that were within their expiration date. Blueberry, berry, and strawberry yogurts change their physical and chemical properties less than other types of yogurts analyzed after expiration. Yogurts containing berries and strawberries, blackberries, and raspberries remain safe at the expiration date, as they do not show the presence of harmful microorganisms such as coliform bacteria, Escherichia coli, Enterobacter spp., Enterococcus spp., Listeria, or Salmonella. Yogurt with berries and strawberries appears to be the most suitable from a microbiological point of view at expiration, as it has a low total mesophilic bacteria count and lactic acid bacteria exceeding 1 × 106 CFU/g. At the time of expiration, this fruit yogurt type (with berries and strawberries) had a total solids content of 21.29%, 5.22% protein, 2.11% fat, 13.19% carbohydrates, 4.07 pH, 26.79% syneresis, 73.21% water retention capacity, 64.78% total phenolic content, and 10.55% DPPH (inhibition percentage). Nevertheless, at the time of expiration, from a sensory perspective (only appearance and consistency, odor, and color, without taste), the yogurt samples that were most appreciated contained blackberries and raspberries. The obtained results indicate that only certain types of fruit yogurts stored unopened at 4 °C may remain safe and edible after the expiration date, but further studies are needed to help the dairy industry and policymakers promote the reduction in food waste in households.