The suggestions are contained in research examining more efficient methods for reducing pathogens in beef jerky, pork trimmings and meat carcasses. The research was produced under a program funded by the Food Safety and Inspection Service (FSIS) and aimed at helping small to very small plants meet hygeine requirements.
One study, on beef jerky processing reinforced the importance of maintaining humidity and controlling the moisture loss from the product in order to achieve an adequate reduction of E. coli O157:H7, Salmonella spp., and Listeria monocytogenes.
The drying procedures currently used by most small processors does reduce the number of pathogens on the jerky. However, drying does not reduce the number enough to meet the kind of reduction the agriculture department is aiming to achieve in the industry.
"Something as simple as adjusting the oven damper during processing shows that control of humidity can be easy to achieve and cost effective and thus should be of particular value to small and very small plants that make jerky," the FSIS researchers stated in their reports. "Plants will, however, need to validate that their methodology achieves these parameters. This research should decrease their operating cost while helping them to ensure food safety and public health protection."
The study found that drying and storing in a vacuum package does result in a reduction of pathogens but not to below the detectable limit. The cause of the reduction of pathogens in storage is not clear.
As long as the water activity of jerky is below 0.70, pathogens will not survive vacuum packaged storage at ambient temperature beyond six weeks.
Some will be due to the lowered water activity but some may be due to pathogens being injured during drying and not being able to adapt to the vacuum packaged atmosphere, the researchers concluded.
Another study found that costs can be reduced if beef jerky processors ensure their wet or dry bulbs used for the drying processes are at a high enough temperature.
The results of the study shows the importance of wet-bulb temperature in achieving the required reduction in pathogens. The researchers recommend that processors use a wet-bulb thermometer or a hygrometer to monitor humidity. They should then use a slide rule to determine wet-bulb temperature from known dry-bulb temperature and other values.
Reductions in Salmonella and E. coli O157:H7 can be achieved in the production of whole-muscle beef jerky by ensuring that high enough wet-bulb temperatures are reached and maintained early in the process.
A third study on meat trimmings supports the use of multiple methods of pathogen reduction in small processing plants rather than single treatments.
"It also appears that the combination of antimicrobial agents that express different modes of action for suppressing pathogen growth and the sequential application of different decontamination sprays are significant factors for obtaining greater reductions in pathogen numbers on beef carcasses at slaughter," the study found.
The study evaluated lactic acid, acidified calcium sulfate and epsilon-polylysine used to decontaminate beef carcasses and trimmings.
The agents are used to reduce the time and cost of sanitizing for small plants and are applied as a warm rinse following standard washing procedures.
A fourth study found that household steam cleaners can effectively reduce pathogens on the surface of meat carcasses processed in small and very small meat processing plants.
The study was conducted in two phases. In the first phase three different commercial household steam or steam and vacuum cleaning systems, were purchased and tested in the laboratory using inoculations of E. coli O157:H7 and Listeria monocytogenes to determine which cleaner was most effective.
The systems ranged in price from $150 to $1,495. The cheapest system, a SteamMax SF 275, was found to be the most effective are reducing pathogens.
In the second phase the cheapest system was evaluated in four different small or very small meat processing plants. The tests revealed that a 180 second steam treatment using the SteamMax cleaner significantly reduced the populations of total aerobes, coliforms, and enterobacteriaceae compared to controls.
Another study found that small beef jerky processors using dehydrators and who have little control over maintaining consistent relative humidity within the drying chamber may find the use of antimicrobial treatments beneficial in achieving the desired level of pathogen reduction.
The studies are available here.