Establishing enhanced Listeria control: Coupling environmental monitoring with risk-based product testing

Prevention and control of Listeria monocytogenes remains a challenge in food manufacturing facilities and methods adopted vary across different production systems and food categories. Regulatory policies also vary from region to region, although there is a convergence across the world towards risk-based approaches. Given these inconsistencies, the objective of this commentary is to reiterate two fundamentally critical components of Listeria control and prevention, and the potential benefits of actively coupling food contact surface testing and risk-based product testing programs.

Prevalence and Distribution of Listeria monocytogenes in Three Commercial Tree Fruit Packinghouses

A 2-year longitudinal study of three tree fruit packinghouses was conducted to determine the prevalence and distribution of Listeria monocytogenes. Samples were collected from 40 standardized non-food-contact surface locations six different times over two 11-month production seasons. Of the 1,437 samples collected, the overall prevalence of L. monocytogenes over the course of the study was 17.5%. Overall prevalence did not differ significantly (p > 0.05) between each year. However, values varied significantly (p ≤ 0.05) within each production season following packing activity levels; increasing in the fall, peaking in early winter, and then decreasing through spring. L. monocytogenes was most often found in the packing line areas, where moisture and fruit debris were commonly observed and less often in dry cold storage and packaging areas. Persistent contamination was attributed to the inability of water drainage systems to prevent moisture accumulation on floors and equipment during peak production times and uncontrolled employee and equipment traffic throughout the facility. This is the first multiyear longitudinal surveillance study to compare L. monocytogenes prevalence at standardized sample sites common to multiple tree fruit packinghouses. Recommendations based on our results will help packinghouse operators to identify critical areas for inclusion in their L. monocytogenes environmental monitoring programs.

Applications of Natural Antimicrobials in Food Packaging and Preservation

In the food science field, the term “antimicrobial” basically refers to active substances of synthetic or natural origin, that are directly or indirectly present in a specific food, packaging material or food contact surface that affect the viability or the growth of microorganisms in that matrix [...]

Evaluasi Penerapan Good Manufacturing Practice dan Sanitation Standard Operating Procedure pada Rumah Pemotongan Hewan Unggas di Bogor

Microbial contamination in chicken meat is caused by unsanitary practices during slaughtering in poultry slaughtering house. Poultry slaughtering house need to apply Good Manufacturing Practice (GMP) and Sanitation Standard Operating Procedure (SSOP) system to produce the standard microbial requirements of meat. This study was aimed to evaluate the implementation of GMP and SSOP and categorize 30 slaughtering houses located in Bogor. Observation was carried out in 4 modern slaughtering houses (RPH-U) and 26 traditional slaughtering houses (TPH-U). Parameter evaluation was determined based on the Indonesian national standard SNI 01-6160-1999 and the veterinary control certificates which consisted of eight aspects of GMP and six aspects of SSOP. The categorization was clustered in five levels. The results showed that modern slaughtering houses were categorized into 1st and 2nd level, whilst traditional slaughtering houses were categorized into 2nd and 3rd level. The highest incompliance of GMP in modern slaughtering house was the waste treatment aspect (31%) and in traditional slaughtering house was the cold storage presence aspect (95%). The highest incompliance of SSOP in modern slaughtering house was the sanitation facilities and avoiding cross-contamination aspect (21%) and in traditional slaughtering house was the cleanliness of food contact surface aspect (97%). There are some recommendations for improvement the fulfillment of GMP and SSOP aspects based on the critical parameters. Keywords: chicken meat, Good Manufacturing Practice, modern slaughteringhouse, Sanitation Standard Operating Procedure, standard slaughteringhouses

Efficacy of ATP Monitoring for Measuring Organic Matter on Postharvest Food Contact Surfaces

ABSTRACT The Food Safety Modernization Act, specifically the Produce Safety Rule, requires growers to clean and sanitize food contact surfaces to protect against produce contamination. An ATP monitoring device is a potential sanitation tool to monitor the efficacy of an on-farm cleaning and sanitation program that could help growers meet regulatory expectations mandated by the Produce Safety Rule. This ATP monitoring device uses bioluminescence to detect all ATP (found in bacteria and produce matter cells) from a swabbed surface. Because little work has been done to test the efficacy of these tools under postharvest conditions, the present study evaluated ATP measurement for postharvest food contact surface cleanliness evaluation. Concentrations of leafy greens (spinach, romaine, and red cabbage, with or without Listeria innocua) were used as organic matter applied to stainless steel, high-density polyethylene plastic, and bamboo wood coupons to represent postharvest food contact surfaces. The ATP levels on the coupons were then measured by using swabs and an ATP monitoring device. Results showed that the concentration of L. innocua and leafy greens on a food contact surface had a highly significant effect on the ATP monitoring device reading (P < 0.0001). The ATP monitoring device had a lower limit of detection for L. innocua at 4.5 log CFU per coupon. The type of leafy green on a food contact surface did not affect the ATP reading (P = 0.88). Leafy greens with added L. innocua had a higher ATP reading when compared with saline and L. innocua, demonstrating the presence of leafy green matter contributes to ATP reading when combined with L. innocua. The different food contact surfaces had different ATP response readings (P = 0.03), resulting in no detectable levels of bacteria and/or leafy green material from bamboo wood surfaces (P = 0.16). On the basis of our results, the ATP measurement is an appropriate tool to measure produce or bacterial contamination on stainless steel or high-density polyethylene plastic surfaces; however, it is not recommended for wood surfaces. HIGHLIGHTS

Bacteriophage Intervention Effectively Kills Listeria on Food Contact Surface Materials

ObjectivesListeria is a pathogenic bacterium that is widespread in nature and can enter food processing plants through many vectors, like raw materials, process waste and personnel. Food processors work hard to keep Listeria out of the environment, but it can at times be found from food contact surfaces to floor drains. The sanitation can be compounded when equipment is pitted or cracked creating a harborage or niche in which Listeria can grow. Many control strategies for cleaning and biofilm removal have been put into place but may not suffice in eliminating Listeria from the food contact surface or environment. Bacteriophages are now being used to tackle these pathogens in food processing environments. Since they only target specific bacteria, they are harmless to humans, animals and plants, while effectively eliminating Listeria.This study determines the efficacy of a commercially available bacteriophage product, PhageGuard Listex, against Listeria on commonly found materials in food processing plants (stainless steel and UHMW polyethylene). Efficacy was determined by applying two phage concentrations, as well as two exposure times.Materials and MethodsOvernight cultures of L. monocytogenes ATCC13832 and L. innocua ATCC51742 were mixed in equal parts to create a Listeria cocktail (2 × 109 CFU/cm2). Sterile coupons (100 cm2) of stainless steel or UHMW polyethylene were artificially inoculated with the cocktail at 2.5ML/cm2 and left to dry at 37°C until completely dry. Subsequently, coupons were treated with 2 × 107 or 1 × 108 Plaque Forming Units (PFU)/cm2 using a spray system and incubated at room temperature for 1 and 3 h, before retrieval and enumeration of bacteria on selective agar plates. Sample size n:3. Results were analyzed using two-way ANOVA, with Dunnett’s multiple comparisons test on the normalized data.ResultsA dose dependent response to the phage treatment was observed, where an increasing phage concentration resulted in an increase in Listeria kill on both surfaces. On stainless steel, a treatment dose of 2 × 107 PFU/cm2 resulted in a statistically significant bacterial reduction of 1.27 log after 1 h (p value < 0.0001), while application of 1 × 108 PFU/cm2 showed a 2.16 log reduction (p value < 0.0001). On UHMW polyethylene, a bacterial reduction of 0.47 log was observed 1 h after applying 2 × 107 PFU/cm2, while the application of 1 × 108 PFU/cm2 led to a reduction of 1.95 log. However, these reductions were not statistically significant (p value > 0.05). After 3 h of treatment, the reductions were slightly higher in both materials (Table 3). After this time, the difference between control and 5% treatment on UHMW polyethylene obtained a p-value < 0.05.ConclusionPhage technology is an easy and safe intervention which can be used as an additional tool to control Listeria in processing environments. The above results indicate that the commercially available phage solution, PhageGuard Listex, can reduce Listeria contamination on food contact surfaces by 0.4 to 3.4 logs after 3 h of treatment.Table 3Log reduction of Listeria cells after applicatio nof two bacteriophage concentrations, measured at 1 and 3 h post phage treatment