1. Comparison of selected hand hygiene efficacy test methods by key step or variable Key Step or Variable ASTM E2783 (Time Kill) EN 1276 Chlorine Equivalency (former USDA E2/E3 rating) ASTM E1174 ASTM E2755 ASTM E2946 ASTM E2011 EN 1499 EN 1500 In Vitro In Vitro In In Vivo In Vivo In Vivo In Vivo In Vivo In Vivo Purpose / Target Application in Design “In vitro” hand hygiene product evaluation “In vitro” activity of disinfectants and hand hygiene products “In vitro” designed to test efficacy of halogen based disinfectants and sanitizers “In vivo” product evaluation (“healthcare personnel hand wash”) “In vivo” activity of hand hygiene personnel hand rubs “In vivo” activity of food handler hand hygiene formulations “In vivo” antiviral activity of hand hygiene formulations “In vivo” hand washes – ensure a minimum performance standard “In vivo” hand rubs – ensure a minimum standard Test Organism(s) Any BSL 1 or 2 organisms; we could recommend a specific list that are highly food relevant (e.g. e. Coli, listeria, salmonella, etc.) Ps. aeruginosa ATCC 15442, E. coli ATCC 10536, S. aureus ATCC 6538, hirae ATCC 10541 S. aureus ATCC 6538 S. typhi ATCC 6539 Serratia marcescens and E. coli Serratia marcescens ATCC 14756 S. aureus ATCC 6538, or 33591 E. coli ATCC Human Rotavirus, Human Rhinovirus Type 37, Feline calicivirus, Human Adenovirus Type 5 E. coli K12 NCTC 10538 E. coli K12 NCTC 10538
Soil Type(s): None Flexible: Can be chosen on the condition of use Inoculated broth 4.5 mL of inoculums in nutrient broth 0.2 mL of inoculum in nutrient broth Beef broth is “moderate” soil, Hamburger is “heavy” soil Bovine serum Inoculated broth Inoculated broth Soil Load (Quantity): Volume of the inoculum in Nutrient broth used 0.3g/L clean conditions; 3 g/L dirty conditions 10 µl of inoculated broth for tube 1 and total 100 µl for tube 10 4.5 mL of inoculums in Nutrient broth 0.2 mL of inoculum in nutrient broth 4.5 mL of Beef broth for moderate soil Handling contaminated hamburger for 2 min 5% in the virus inoculum Amount of inoculated broth which ends up on the hands during immersion of the hands None specifically added. Just dried TSB from inoculating broth Method of Contamination: Inoculation of the product Inoculation of the product Inoculation of the product 3 -1.5 mL of an overnight broth culture of the test organism of a concentrated broth suspension of the test organism 4.5 mL of Beef broth for moderate soil Handling contaminated hamburger for 2 min 1.5 mL of the suspension, 90 sec spread, 90 sec dry Or 20µL of virus suspension on each finger tip Immersion into seeded broth Immersion into seeded broth Baseline Recovery Value): Not specified 1.5x108-5x 108 N/A 5x108-1x109 Liquid suspension used for contamination. ≥108 cfu/hand (Usually 8.5-9.0 log10 cfu/hand) Suspension 1x108 The virus “pull” shall contain ≥107 infective unit/mL Inoculum 2x108-2x 109 Log pre-values at least 5 Inoculum 2x108-2x 109 Log at
Recovery is not specified least 5 per mL Test Article Application Details: N/A N/A N/A 5 mL of the test product during handwashing using 40°C water for 1 min handwashing 1.5 ml of a test material (calculations for foaming materials provided) 5 mL of the test material Wash for 30±5 sec, rinse for 30±5 sec Volume specified by manufacturer 3 ml applied and washed for 30 or 60 sec +15 sec or following manufacturer instructions 3 ml applied and rubbed for 30 seconds, then sampled Number of Subjects / Replicates (Minimum, Recommended) N/A N/A N/A Not specified FDA CDER asks for at least 12 subjects At least 8 subjects Total depends on number of test materials, study purpose, and regulatory requirements governing the study. At least 8 subjects At least 6 subjects At least 12 subjects 18-22 subjects Internal Reference: None None Referenced Chlorine solution None None None None Soft soap (British 1993) 200g/L 2x3ml of 60% isopropanol rubbed for 60 seconds total
Acceptance Criteria: None 5 log reduction Test article is at least equivalent to 50 ppm chlorine None in the test method. Per 2015 FDA HC TFM: 2 Logs after the 1st application, 3 Logs after 10th application None in the test method. None in the test method. None in the test method Statistically non-inferior to the reference product Statistically non-inferior to the reference product Can bland Handwash be a benchmark? Yes, not in the test method N/A N/A Yes, not in the test method N/A Yes, not in the test method Yes, not in the test method N/A N/A Product dilution Undiluted Undiluted Undiluted Undiluted Undiluted Undiluted Undiluted Undiluted Undiluted Contact time Flexible; most typical is 15 sec, 30 sec and 60 sec. 5 min 1, 2.5 and 5 min 30 sec lather + 30 sec rinse 1.5 mL application volume, Rub hands are dry. Or manufacturer’s 30±5 sec 10-20 sec for handwash, 20-30 sec for hand rub, or other times use condition time 30 or 60 sec +15 sec rinse or following manufacturer instructions 30 sec Table 2. Comparison of selected hand hygiene test methods by strengths and limitations and suitability for inclusion in Model Food Code
Method Strengths Limitations Expected variability and Relevance and Fit for Food Code (H/M/L) Recommended for CFP & Food Code ASTM E2783 (Time Kill) “In vitro” test, relatively inexpensive, can be run with many organisms and by many labs with good reproducibility. Large amount of data and experience using this method “In vitro” test (i.e. results will not necessarily predict real world hand hygiene results or the in-vivo methods) Results more variable when the product has high foam; results are highly dependent of the mixing technique High: Good screening test, should be required as a means to ensure broad spectrum antimicrobial effectiveness before “in vivo” testing. Yes Chlorine Equivalency “In vitro” test. Long history of use posed by working with S. typhi (typhoid fever) Data is not relevant for hand antiseptics in general, especially those that do not contain halogen based active ingredients Products with border line efficacy have high variability in results Low No EN 1276 “In vitro” test Includes options of to be added, based on the industry. Could be tested for clean and dirty conditions Some of microorganisms are not relevant for food retail use The test method is not designed for chemistries affected by soil No Low No