Data gathering

For this project, we used Amazon reviews of Grocery and Gourmet Food products and enforcement reports from the Food and Drug Administration. These enforcement reports are made available as weekly CSV files going back to 2012. It is possible to search the FDA’s website for all data on food products, but unfortunately the download is limited to 1,000 rows at a time. We also attempted to access the data in a public S3 bucket, but found a large portion of the data was missing, so we ultimately chose to manually download the weekly CSV files and combine them ourselves.

As our goal was to predict food recalls based on product reviews, our next step after acquiring the data was to unite these two datasets.

The most reliable way to match recalled products with Amazon reviews was by using the item’s Universal Product Code (UPC), which is the number that appears on a barcode and uniquely identifies that particular product. The FDA enforcement reports often (but not always) contained the UPC or UPCs of the product(s) being recalled within a larger text field. We used regular expressions to extract these codes and, in some cases where partial UPCs were provided, generated lists of the possible complete UPCs from the partial codes.

Amazon uses its own identifier, the Amazon Standard Identification Number (ASIN), to identify products. Fortunately, conversion tools such as exist to convert UPCs to ASINs. Once we matched the UPCs of recalled products with their corresponding ASINs, we were able to start exploring the differences in reviews for recalled and non-recalled products.

Number of reviews for recalled vs. non-recalled products

Not surprisingly, there are vastly more reviews for products that have not been recalled than there are for products that have been recalled, since most food products never get recalled. Over 1,000,000 reviews were for non-recalled products, and just over 5,000 were for recalled products. Reviews for recalled products made up less than one half of one percent of the total dataset.

The number of reviews for both recalled and non-recalled products has increased over time, likely tracking Amazon’s popularity as a website and/or the number of food products they carry.

Number of reviews over time

The Amazon review data also includes the rating (1-5 stars) that the reviewer gave the product. For both recalled and non-recalled products, five-star reviews are by far the most common.

Rating distribution for recalled and non-recalled products