Effects of 5% lactic acid application on Enterobacteriaceae levels and prevalence of Salmonella thro

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Effects of 5 lactic acid application on
Enterobacteriaceae levels and prevalence of
Salmonella through a low-temperature
edible-rendering process

• P. Bass, K. Belk, J. Scanga, J. Sofos, G. Smith
• Colorado State University, Fort Collins, CO

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Beef Fat Trimmings

• Majority of cattle in the US are fed beef
• 590 kg (1300 lb) live wt., YG 2.9, FT 1.22cm
  (0.48 in)
• 375 kg (826 lb) carcass
• 28.6 kg (63 lb) fat trimmings
• Beef fat processed into
• Inedible tallow
• Mixed with lean for ground products
• Finely textured beef

Carcass Estimates CSU Beef Cutout Calculator
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Finely Textured Beef (FTB)

• Recovered lean muscle tissue from beef fat
  trimmings
• Fat content
• Used in formulating
• Sausages
• Restructured processed meats
• Ground beef
• Recovered via low-temperature edible rendering

Image Source http//www.meatsafety.org/safehandli
ng/groundbeef2.jpg
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Low-temperature Edible Rendering
Steam
(30-50C)
Heat Treatment
Pump 1
Separation 1
Solids
Liquid
Separation 2
Serum
Tallow
Pump 2
Pelleter
FTB
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Objectives

• Analyze the effectiveness of a 5 lactic acid
  (LA) solution application on surface
  Enterobacteriaceae (EB) survival and Salmonella
  (SAL) prevalence on beef trimmings passing
  through an on-line spray wash cabinet
• Analyze the effectiveness of a 5 LA solution
  application on EB survival and SAL prevalence at
  differing phases of the commercial operation of a
  low-temperature edible rendering process.

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Treatments

• Day 1 Control
• Day 2 Spray wash cabinet
• 5 LA, 1.4 Bars, 50C, 6 s
• Day 3 LA spray at grinder
• 5 LA, 1.4 Bars, 50C
• Day4 LA spray immediately prior to pelleting
• 5 LA, 1.4 Bars, 50C
• Day 5 LA spray at grinder and immediately prior
  to pelleting
• 5 LA, 1.4 Bars, 50C

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Spray Wash Cabinet

• 1.4 Bars, 50C, 6 s

Manufacturer CHAD Company
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Spray Wash Cabinet

• 7 rows of spray line 2 nozzles (top), 5 nozzles
  (bottom)

Schematics CHAD Company
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Spray Cabinet
Steam
(30-50C)
Heat Treatment
Separation 1
Solids
Liquid
Pump 1
Sampling Points -Grinder -Heat Treatment -Liquid -
Solid -Tallow -Serum -FTB
Separation 2
Serum
Tallow
Pump 2
Pelleter
FTB
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Sampling Procedure (Spray Cabinet)

• Samples were taken immediately prior to and
  immediately after the spray wash cabinet from
  whole pieces of beef fat trimmings
• 4 x 8 cm sterile specimen sponge (Bio Pro)
• Hydrated with 10 mL of 0.1 peptone buffer
• 100 cm2 area of subcutaneous fat surface
• 10 passes horizontally, 10 passes vertically
  (Stopforth et al., 2006)
• Sampled every 30 min of production time on Day 2

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Sampling Procedure (Low Temp)

• Samples taken every hour of production
• Grinder sterile plastic gloves
• Other steps stainless steel ladle, sanitized
  with 70 ethanol solution
• Samples placed in 15.25 x 22.85 cm sterile
  Whirl-pak bags
• Placed in refrigeration
• Shipped overnight

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Sampling Procedure

• Warren Analytical Laboratories, Greeley, CO
• SAL
• Enriched in TSB for 12 h with agitation at 37C
• multiplex PCR screening (Stopforth et al., 2006)
• EB3M Petrifilm Enterobacteriaceae Count Plate
• 1 mL aliquot
• Incubated at 35C for 24 2 h
• EB colony red colony, gas bubbles, light-yellow
  halo

Image Source 3M Petrifilm Enterobacteriaceae
Plate Count Interpretation Guide
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Statistical Analysis

• EB analyzed in PROC GLM, SAS
• Significant at P
• SAL prevalence analyzed in PROC FREQ, SAS
• Fishers Exact Test
• Significant at P

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Spray Wash Cabinet EB Results
a,bDifferences within columns, lacking a common
superscript, differ (P 15
EB Results
a,b,cDifferences within columns, lacking a common
superscript, differ (P 16
SAL Prevalence
x,yDifferences within columns, lacking a common
superscript, differ (P 17
Summary

• Reduction in EB counts when LA was applied at
  spray wash cabinet
• Reduction in EB counts when LA was applied at any
  stage of the process compared to control
• Significant reduction in SAL prevalence on Day 4
  vs Day 1 at the liquid step
• LA did present some color issues in the FTB
• Findings support the potential for LA application
  to lean beef trimmings for the control of EB and
  SAL