*While the full article for this executive summary is currently under peer review, these initial findings are being made available on BeefResearch.org to enable the industry to act on the research, inform the scientific community of ongoing work, and help prevent duplication of research efforts. Once peer review is complete, a link to the published article will be added to this summary.
KEY TAKEAWAYS
- 95.52% of establishments surveyed are not optimally freezing based on temperatures reported.
- 44.89% of establishments surveyed only had still air freezers as their primary freezing method. While effective, still air freezers do not provide ideal wind velocity and have low heat transfer coefficients.
- Large and small establishments face issues with freezer space and exhibit methods of freeze fast and thaw fast.
BACKGROUND
A major concern within the meat industry is the extension of a meat product’s shelf life. While multiple methods have been tried, a simple solution is freezing. Freezing, in comparison to refrigeration, effectively extends the shelf life of the product and does not change the identity of the product like other processes. In addition to freezing, thawing must be considered with product quality. Freezing and thawing can influence product quality factors such as moisture content, protein denaturation, lipid and protein oxidation, color, pH, tenderness, and microbial counts. Poor freezing and thawing practices cause negative product quality factors to increase. The traditional procedure behind freezing and thawing meat is to “freeze fast, thaw slow.” Conventionally, beef was only frozen to prevent spoilage during long transport times when exported, but in the last five years, there has been an increase in the amount of frozen beef in the United States. This increase in frozen products creates potential challenges for a complex production process in meat processing establishments. The purpose of this survey was to capture information pertaining to freezing and thawing parameters such as time, temperature, product type, freezer technology, and other non-direct packaging characteristics. This data will provide vital information essential to conducting targeted research on freezing and thawing practices related to current practices used in the industry.
Methodology
The FSIS list of USDA inspected plants was downloaded using Microsoft Excel Spreadsheet. The list was filtered to only include establishments with the phrases “Meat Slaughter” and “Meat Processing.” Establishments with additional phrases were not filtered out as they are still under inspection for the targeted activities in this survey. Thirty-seven establishments were contacted to take the survey, which included questions regarding freezing and thawing techniques used at their plant. The first subset of questions on the survey gathered general information about the demographics of the plants. The next set of questions was designed to provide information regarding freezing and included questions on freezing time, temperature, freezer technologies, and how the products are frozen. Following the freezing questions focused on thawing: the temperature of the product thawed, the time it takes to thaw, and how the product was thawed. Following the thawing questions, short answer responses focused on the establishment’s ideas on improvement within their plant, pertaining to freezing and thawing practices. Lastlye, establishments were asked if there were noticeable packaging defects as a result from freezing and thawing practices. All data were entered into a Microsoft Excel Spreadsheet. JMP Software (JMP®, Version 10. SAS Institute Inc., Cary, NC, 1989-2021) and Microsoft Excel was used to analyze the data.
Of the total (n=6,917) USDA-FSIS inspected plants, ~61% (n=4,247) of them were identified as being under inspection for “Meat Slaughter” and “Meat Processing.” Of the plants identified, ~42 % (n=1,798) were contacted using the plants contact number given to USDA-FSIS. Of the plants contacted, 221 surveys (n=221) were completed during the first phone call. An additional 40 surveys (n=40) were completed during subsequent phone calls or sent via email, to bring the total completed surveys to 261 (n=261). The highest frequency types of frozen products were primals/subprimals, retail cuts, and trimmings/ground beef (35.24%), followed by retail cuts and trimming/grounds (21.59%), only retail cuts (7.93%), and only trimming/ground (7.49%). The rest were combinations below 6%. The “other” category (57.14%) incorporated burgers or patties, which would represent establishments that only made frozen burger patties. Plants that only froze offal made up 2.64%.
Plants were asked to provide descriptions on how products were frozen. The freezer technologies were dominated by two categories: still air and blast freezers. The frequency of establishments that only had still air freezers was 44.89%, followed by only blast (35.56%). Establishments that used both still air and blast were 9.78% of surveyed establishments. All other combinations were below 5% but included plate, cryogenic, 38 liquid, and “other”. Still air freezers have a lower air velocity and therefore have a lower heat transfer coefficient, resulting in slower freezing. Answers on techniques of freezing resulted in tray freezing (16.52%), boxed freezing in a pallet configuration (16.52%), boxed freezing in a single layer (12.50%), basket freezing (12.50%), boxed freezing on a pallet with spacers (10.71%), and other (10.71%). Reported freezing time and temperature were collected, and the most common freezing intervals were 6-24 hours (50.00%), followed by 24-48 hours (24.81%), and then less than 6 hours (10.08%). Average freezing temperatures were -22.17 °C, with a minimum temperature of -1.67 °C and a maximum of -51.11 °C. Establishments that froze at temperatures between -40 and -50 °C would be considered optimal and have higher quality factors if all experimental parameters were followed. Of the surveyed establishments (only taking temperature into account), ~4.48% would have optimal freezing, and the rest (95.52%) would be considered slow freezing.
Of the plants surveyed (n=261), 108 establishments (n=108) thaw products in some capacity. The most common combination of how products are thawed was in a box in a single layer (27.27%), followed by in a box in a pallet configuration (13.64%), and tray thawing (6.82%). Some less common thawing methods were liquid (4.55%) and microwave (1.15%). The highest average frequency of thawing times was 24-48 hours (23.84%), followed by 48-72 hours (16.56%), 6-24 hours (14.57%), and 144-168 hours (10.60%). The average thawing temperature was 3.06 °C, with a maximum and minimum thawing temperature of 19.72°C and -1.94 °C respectively. The surveyed maximum thawing temperature of 19.72 °C is beyond recommended settings due to high microbial spoilage and pathogen growth at those temperatures compared to refrigerated temperatures (2 °C).
Additional information was collected by asking opinion-based questions to plant employees to obtain industry insight on potential issues in the beef industry. The first question asked for areas within each establishment where freezing and thawing practices could be improved. A common response (53.5%) was the need for increased freezer space and wanting to freeze faster (28.28%). Establishments’ employees were also asked the most common packaging damage during freezing or thawing. Employees responded with leakers (50.00%) and packaging becoming brittle during freezing (27.78%).
Implications
Findings demonstrate the need for areas for improvement in freezing and thawing practices in the beef industry. A large proportion of plants lack effective freezing methods to preserve beef quality. This data revealed that a large portion of establishments are using freezing methods that may negatively impact product quality. Additional information is needed to explore interactions between freezer temperature and how packaging type and boxing configuration impact the product's freezing rate. Also, most establishments that freeze products were interested in methods to freeze faster, provided these technologies were available at affordable prices and could be integrated into existing production environments. Overall, the results from this survey indicate that additional information or the development of best practices for freezing and thawing might be needed to ensure that beef quality is not negatively impacted.