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N-Nitrosopyrrolidine (NPYR) has been detected and confirmed at the ppb level in a significant number of fried bacon samples. NNitrosoproline (NPRO) has been assumed to be the primary precursor of NPYR, but there are conflicting reports about its precise role. A method was developed for determining NPRO and a survey of 60 cured meat samples was conducted. No NPRO was detected in uncooked, conventionally cured bacon, Canadian bacon, ham, salt pork, pork roll or pastrami. NPRO was detected and confirmed in 1 of 7 dry cured bacon samples (106 ppb), 8 of 12 dry cured ham samples (18-604 ppb), and 5 of 6 samples of pork side meat (86-411 ppb). The results suggest the NPRO may not be the main precursor of NPYR in bacon, but may have a role in nitrosamine formation in dry-cured products.

Chicken and turkey frankfurter emulsions and ground commercial frankfurters were treated with sorbic acid or potassium sorbate together with several acidulating agents. These were inoculated with 400 spores/g of a mixture of 21 strains of C. bofulinum (12 of type A, 9 of type B) and canned under vacuum in 208 X 107 aluminum tab cans. The cans were temperature abused at 30°C. Chicken emulsions with sodium acid pyrophosphate (used for commercial frankfurters) showed can swelling in 2 days; turkey emulsion cans swelled in 4 days. The mean swell times for chicken and turkey were, respectively: 7 and 15 days with 0.52% potassium sorbate and 13 and 35 days with 0.40% sorbic acid. Acidification of emulsions with H,PO, or glucono-S-lactone to a pH as low as 5.4 did not increase the mean swell times; however, in combination with 0.4% sorbic acid the mean swell times were increased over those of the sorbic acid alone. Citric acid increased mean swell times in turkey but not in chicken emulsions. For poultry emulsions and poultry frankfurters commercially prepared with 0.2% sorbic acid, acidification with H,PO, to pH 5.7 resulted in appreciable increases in mean swell times; 0.4% sorbic acid without H,PO, was more effective. Indigenous microflora, causing gas production in the cans, were also inhibited by 0.4% sorbic acid and by H,PO,-acidified 0.2% sorbic acid. Finished frankfurters generally behaved the same as the emulsions in C. botulinurn inhibition; however, they gave better protection than the emulsions when both were treated with 0.2% sorbic acid plus H, PO,.

The variability in amine concentration among pieces of pork belly can be seen by comparing the fresh bellies obtained from the two processors. The amines present are the end products of tissue or bacterial metabolism and may reflect the history (pre-and postslaughter treatment) of the belly. However, since no pattern is evident, i.e. no belly or treated product contains a higher concentration of all the amines tested, it appears that the variability is random and differences are not due to either the curing treatment or the cooking-smoking step. LITERATURE CITED