Estimation of Spoilage Bacterial Load on Meat by Fluorescein Diacetate Hydrolysis or Resazurin Reduction

Abstract

Resazurin reduction time (RR), fluorescein diacetate hydrolysis (FDA), and aerobic plate count (APC) were monitored in aerobically packaged beef steaks stored at 4ЊC. FDA hydrolysis increased, while RR decreased with increased APC. As bacterial load increased from ca. 10 2 CFU/cm 2 to 10 8 CFU/cm 2 , FDA activity (A 490 ) increased from 0.1 to 0.6 units and RR decreased from 22 hr to Ͻ1 hr. Linear regression performed between APC and RR, and APC and FDA revealed r-values of 0.94 (PϽ 0.001) and 0.92 (PϽ 0.001), respectively. Results indicated that RR and FDA could be used as rapid methods to estimate spoilage bacterial load in aerobically stored meat.

Reproduction and metabolism at − 10°C of bacteria isolated from Siberian permafrost

“…To determine if activity levels were limiting organisms at low temperatures, we examined the metabolic activity of isolates via the reduction of resazurin (Venkitanarayanan et al ., 1997). The kinetics of resazurin reduction for four different isolates (2b, 3a, 5 and 8) at four different temperatures (22, 10.5, 4, − 10°C) were determined.…”

Quality Assessment of Filtered Smoked Yellowfin Tuna (Thunnus albacares) Steaks

“…Approximately one‐half of each steak was blended using a Handy‐Chopper™ (Black‐Decker, Shelton, Conn., U.S.A.). Total of 11 g of the blended tissue were transferred into individual sterile Whirlpak bags containing 99 mL of sterile Butterfields Phosphate buffer and pulsified, using a Pulsifier™ (Filtaflex Ltd., Almonte, Ontario, Canada) for 60 s. This was followed by standard dilutions and plating using the spread plate technique onto plate count agar and incubated at 25 °C for 48 h following accepted methods of sampling, preparation, and enumeration (Banwart 1989; FDA 1995; Venkitanarayanan and others 1997; Jay 2000). Mean values represented the 3 determinations.…”

Effect of higher temperature exposure on physicochemical properties of frozen buffalo meat

“…The FDA hydrolysis value reached beyond the acceptable value for samples T3 and T6, T2 and T5, and T1 and T4 on day 3, 5 and 7 of refrigerated storage respectively which coincide with of spoilage in stored buffalo meat. Venkitanarayanan et al [8] reported a FDA hydrolysis in biceps femoris steaks under thawing and n=3, C=Control, T1=Treatment 1 (exposed at 25±1°C for 6 h), T2=Treatment 2 (exposed at 25±1°C for 12 h), T3=Treatment 3 (exposed at 25±1°C for 18 h), T4=Treatment 4 (exposed at 37±1°C for 4 h), T5=Treatment 5 (exposed at 37±1°C for 8 h), T6=Treatment 6 (exposed at 37±1°C for 12 h), ND=Not detected. *The spoiled meat sample was analyzed to study the extent of variation in parameters due to prolonged storage.…”

“…The FDA hydrolysis of meat samples were measured according to the procedure described by Venkitanarayanan et al [8] with suitable modifications. One gram of meat was drawn from each sample, observing necessary aseptic precautions.…”

“…A mean ERV value of 19.3 ml was reported in buffalo meat on day 4 of chiller storage, which was significantly lower than the zero day value of 24 ml [7]. As bacterial load increased from 10 2 cfu/cm 2 to 10 8 cfu/cm 2 , in biceps femoris steaks during thawing and exposure to 25°C, flourescein diacetate (FDA) hydrolysis activity (A490) increased from 0.1 to 0.6 units [8]. Sum of free amino acids (FAA) along with water soluble protein content increased in meat during storage and this corresponded well with colony counts, particularly with meat having high glucose concentration [2].…”