Incidence of Canned Food Spoilage at the Retail Level

Abstract

Swelled cans were collected over a 17-month period from outlets of two supermarket food chains. Each swelled can was classified by product and the probable cause of the swelled condition. Using weekly sales volume data for each outlet, the incidence rate of swelled cans for each type of food was estimated. The incidence rates ranged from 2.1 to 78.4 swelled cans per 100,000 units sold, depending upon the type of food. Of the 1.104 swelled cans collected, 314 (28.4%) were found to have major container defects which were assumed to have resulted in the swelled condition. Microbiological analyses were performed on the products in the remaining 790 cans; the following results were obtained: (a) typical leaker spoilage, 86%; (b) typical underprocessing spoilage, 7o/o: (c) thermophilic spoilage, 1 o/o and (d) nonmicrobial swells, 6%. Using vacuum testing and double seam measurements, the causes of the leakage were determined as follows: (a) poor or questionable quality canner's end double seam, 51 o/o; (b) leaks at locations other than the double seam, 26% and (c) poor or questionable quality manufacturer's end double seam, 4%. It was concluded that examining swelled cans of low-acid foods at the retail level is a valid method for evaluating the canning operation of commercial food processing. When shelves are stocked in retail food markets, food packages that appear to have failed are normally segregated for disposal. Among these failed packages are low-acid canned foods which may be badly dented, or show signs of swelling or leakage. During the period from 1973 to 1975, this source of swelled low-acid canned foods was utilized in a project to gather information on the quality of commercial canned food operations. The objectives of this study were to determine the incidence of swelled cans at the supermarket level and determine the cause for the swelled condition. In this report, we will discuss the collection and incidence of swelled cans, as well as summarizing microbiological and container evaluations. Detailed results of the micro-biological and container analyses are reported by Davidson eta!. and Davidson and Pflug (2,3). SWELLED CAN COLLECTION Arrangements were made with the management of two Minneapolis· based supermarket chains for up to 13 of their outlets in the Minneapolis-St. Paul area to save identified swelled cans for our project. Store managers were informed of the project by letter from the district manager. Each of the potential collecting stores was visited by the project leader, and the program was explained to the store managers. To facilitate collection, each store was provided with a special collection container which was clearly labeled. Each of the stores was visited weekly over a 17-month period to collect the swelled cans. All the data gathered on swelled cans were coded on forms to facilitate handling by a computer. Each can was assigned a number and the following information recorded: product, manufacturer (or distributor). can code, date and year collected. The status of swell of the can, i.e., flat, flipper, springer, soft swell or hard swell. was determined at this time. The parent organization of the stores where swelled cans were collected provided us with weekly sales volume data for those types of canned foods where swelled cans were collected.