Risk of Salmonellosis from Chicken Parts Prepared from Whole Chickens Sold in Flow Pack Wrappers and Subjected to Temperature Abuse

Abstract

The flow pack wrapper is a popular packaging choice for retail sale of whole chickens. However, it may provide a favorable environment for growth and spread of Salmonella within the package, leading to an outbreak of salmonellosis. To investigate this possibility, a process risk model was developed that predicted the risk of salmonellosis from chicken parts prepared from whole chickens sold in flow pack wrappers and subjected to proper storage (6 h at 4°C) or improper storage (72 h at 15°C) before preparation. The model had four unit operations (pathogen events): (i) preparation (contamination), (ii) cooking (death), (iii) serving (cross-contamination), and (iv) consumption (dose-response). Data for prevalence, number, and serotype of Salmonella on chicken parts were obtained by whole sample enrichment, real-time PCR. Improper storage increased (P < 0.05) prevalence of Salmonella on raw chicken parts from 10.6% (17 of 160) to 41.2% (66 of 160) and incidence of cross-contamination of cooked chicken from 10% (4 of 40) to 52.2% (24 of 46). Improper storage also increased (P < 0.05) the number (mean ± standard deviation) of Salmonella from 0.017 ± 0.030 to 3.51 ± 1.34 log per raw chicken part and from 0.048 ± 0.089 to 3.08 ± 1.50 log per cooked chicken part. The predominant serotypes isolated (n = 111) were Typhimurium (34.2%), Typhimurium var 5- (20.7%), Kentucky (12.6%), Enteritidis (11.7%), and Heidelberg (8.1%). When chicken was properly stored before preparation, the model predicted that risk of salmonellosis was low and sporadic with only six cases per 100 simulations of 10 chicken parts. However, when 0.1 to 1% of chickens were improperly stored before preparation, the model predicted that salmonellosis would increase (P < 0.05) linearly from a median of 7 (range, 1 to 15) to a median of 72 (range, 52 to 93) cases per 10 chicken parts. These results indicated that the flow pack wrapper provided a favorable environment for growth and spread of Salmonella within the package and that even when only a small percentage of packages were subjected to improper storage before preparation, the risk and size of an outbreak of salmonellosis from chicken parts increased significantly.

Process risk model for Salmonella and ground chicken

“…Therefore, to provide a better simulation of dose-response, a model (i.e. disease triangle, dose-response model) that is based on outbreak and human feeding trial data and that produces nonsigmoid-shaped dose-response curves and that considers differences in virulence among serotypes of Salmonella, differences in food factors and difference in resistance among consumers was modified and used in the present study (Oscar 2017b). Another common approach in process risk modelling is to express dose-response as a probability of illness (Straver et al 2007;Smadi and Sargeant 2013).…”

“…Samples for qPCR were collected at 6 h of WSE in 400 ml of BPW incubated at 40°C and 80 rev min À1 . The standard curve had an enumeration range from 0 to 4Á24 log or 1 to 17 348 per 25 g. The standard curve was developed with Salmonella serotypes Newport, Kentucky, and 8,20:-:z 6 , which were isolated from chicken parts in previous studies (Oscar 2013(Oscar , 2014(Oscar , 2017b, and with serotype Infantis, which was isolated from GC in the present study. The highest C T values at each dose of Salmonella were used to develop the standard curve and provided a conservative (fail-safe) estimate of log number as explained and justified in previous studies (Oscar 2014(Oscar , 2017b.…”

“…The PRM was developed by combining the contamination model (Fig. ) with a published (Oscar ) thermal inactivation model for Salmonella and a published (Oscar ) disease triangle, dose–response model for Salmonella . The thermal inactivation model (Fig.…”

Predictive model for growth of Salmonella Newport on Romaine lettuce

“…Cross‐contamination of RTE salad vegetables with Salmonella from raw chicken followed by growth during meal preparation are important risk factors for human salmonellosis. Oscar () quantified natural cross‐contamination of RTE cooked chicken with Salmonella from raw chicken during simulated meal preparation. When raw chicken was properly stored (6 hr at 4°C) before meal preparation, 10% of RTE cooked chicken portions were cross‐contaminated with low (0–0.2 log) numbers of Salmonella from unwashed utensils (i.e., cutting board, knife, and hands) used to prepare raw chicken for cooking.…”

“…Oscar () also quantified natural cross‐contamination of RTE cooked chicken with Salmonella from raw chicken that was improperly stored (72 hr at 15°C) before meal preparation. He found that 52% of RTE cooked chicken portions were cross‐contaminated with 0.3–6.2 log of Salmonella from unwashed utensils used to prepare raw chicken for cooking.…”